Real estate math guide
Real estate commission math
Write each rate beside the amount it applies to. A brokerage side, a licensee share and a referral fee can all use different bases. Follow the order supplied by the question, then check that the dollars add up. Every rate in the examples is hypothetical, not a required or typical Illinois fee.
Last reviewed:
The short answer
Commission equals the stated fee base multiplied by the rate as a decimal. To find the base, divide the fee by the decimal rate. To find the percentage rate, divide the fee by its base and multiply by 100. For splits and deductions, use the base and order stated for each step. Do not assume a standard rate, equal brokerage split or automatic referral order.
Reviewed October 25, 2026. PSI National XI.A.1 includes seller net, and Illinois II.E covers compensation requirements. The full national Calculations domain has 7 of 100 scored questions. Commission splits are not a separately named calculation family in that outline; percentage work can support seller-net and compensation questions. These examples teach arithmetic, not entitlement to a fee, a legal payment exception or a tax result.
Find the base before multiplying
- Identify the requested amount. Total brokerage compensation, a firm's side, a licensee's share and take-home income are different targets. A fee split does not by itself calculate taxes or every business expense.
- Name the base for each rate. It may be the sale price, rent for a stated term, a brokerage side or an already reduced amount. A seller credit does not automatically reduce the commission base. Use the agreement or facts supplied.
- Convert percentages to decimals. Divide by 100:4.5% is 0.045 and 0.75% is 0.0075. Multiply base by decimal rate. To reverse the calculation, divide by the known nonzero rate or base as appropriate.
- Follow the stated tiers, sequence and deductions. Calculate each marginal tier separately. Distinguish a minimum fee from an extra fee. A flat charge before a split can produce a different result from the same charge after the split.
- Reconcile the result. Broker and licensee allocations should account for the available fee after the stated deductions. Deduct a seller-paid fee once in the seller ledger. Keep precision until the problem's rounding step, and follow any specific cents or whole-dollar instruction.
| Target | Formula | Most common trap |
|---|---|---|
| Total commission | Base x decimal rate | Use percent as whole number |
| Compensation base | Commission / decimal rate | Multiply instead of divide |
| Commission rate | Commission / base x 100 | Leave answer as decimal |
| Brokerage side | Total fee x stated side rate as a decimal | Use sale price again |
| Licensee gross share | Named internal-split base x decimal split | Apply split to total fee |
| Referral amount | Named referral base x referral rate | Use the wrong referral base or deduction stage |
| Tiered fee | Tier 1 fee + Tier 2 fee | Apply high rate to full price |
| Lease fee | Stated rent base x fee rate | Assume annual or monthly base |
| Seller net | Sale proceeds - all stated seller debits, counted once | Subtract commission twice |
| Effective rate | Total fee / full base x 100 | Average tier percentages |
| Minimum instead of percentage | Greater of the two stated amounts | Add a minimum as if it were an extra fee |
| Reverse seller net | (Target net + fixed seller costs) / (1 - fee rate) | Use this when other costs also vary with price |
| Cap on company share | Apply the stated remaining cap to the covered share | Treat every fee or future deal as cap-free |
The distinctions that matter
| Distinction | How it works | What to notice |
|---|---|---|
| Commission rate vs. commission dollars | The rate is a percentage of the stated base. Commission dollars are the rate multiplied by that base. | Percent input versus money output. |
| Total fee vs. brokerage side | Total fee is the full transaction compensation calculated under the stated agreement. A brokerage side is the portion allocated to one firm. | Whole pie versus one firm's slice. |
| Brokerage split vs. licensee split | A firm-to-firm allocation and an internal sponsor-licensee allocation are different steps. Referral and other deductions follow the specific bases and order stated, rather than one universal sequence. | Firm-to-firm first, firm-to-licensee second. |
| Gross share vs. net pay | A stated split produces a gross allocation. Taxes, business expenses and other contract deductions may remain; a practice result is not automatically take-home income. | Before deductions versus after deductions. |
| Fee obligation vs. funding source | Obligation identifies who promised payment. Funding source identifies whose money is used at closing to satisfy that obligation. | Who owes versus where dollars come from. |
| Percentage fee vs. flat fee | A percentage fee changes with its base. A flat fee remains the stated dollar amount unless another provision changes it. | Variable multiplication versus fixed dollars. |
| Tiered rate vs. blended rate | Tiered rates apply different percentages to separate portions. The blended rate is total fee divided by the full base after the tiers are calculated. | Marginal pieces versus one effective percentage. |
| Referral percentage vs. co-broker percentage | A referral fee compensates a referring brokerage under the referral agreement. A co-broker split allocates transaction compensation between participating brokerages. | Introduced business versus transaction side. |
| Commission deduction vs. seller payoff | Commission is brokerage compensation. A payoff satisfies secured debt. Both can reduce seller net but represent different obligations. | Service fee versus lien debt. |
| Negotiated rate vs. fixed market rate | Use the actual independently agreed fee. A familiar example percentage is not a legally required or marketwide rate, and competitors must not coordinate their prices. | Read the contract, never invent a norm. |
Work through the facts
Basic percentage fee
A brokerage agreement states a fee equal to 4.5% of a $425,000 sale price. No other fee component applies.
- Convert 4.5% to 0.045.
- $425,000 times 0.045 equals $19,125.
Answer: The total brokerage fee is $19,125.
Reverse the formula
A brokerage fee is $18,500 and equals 5% of the sale price. What was the sale price?
- The unknown is the base, so divide rather than multiply.
- $18,500 divided by 0.05 equals $370,000. Checking: $370,000 times 0.05 equals $18,500.
Answer: The sale price was $370,000.
Two-level split
Total transaction compensation is $24,000. The two brokerages split it 50-50, and a sponsored licensee receives 70% of the licensee's brokerage side.
- The brokerage side is $24,000 times 0.50, or $12,000.
- The licensee share is $12,000 times 0.70, or $8,400. The combined factor is 0.50 times 0.70, or 0.35 of total.
Answer: The sponsored licensee's gross share is $8,400.
Tiered fee
A written agreement charges 5% on the first $300,000 and 3% on any sale-price amount above $300,000. The property sells for $440,000.
- First-tier fee is $300,000 times 0.05, or $15,000.
- The excess is $140,000, and $140,000 times 0.03 is $4,200. Add the tiers.
- The blended rate is $19,200 / $440,000 x 100, about 4.36%. It is not the simple 4% average of the two tier rates.
Answer: The total tiered fee is $19,200.
Referral off the brokerage side
A brokerage receives a $15,000 side. Its referral agreement requires 25% of that gross side to the referring brokerage. The sponsored licensee then receives 70% of the remainder.
- Referral is $15,000 times 0.25, or $3,750, leaving $11,250.
- The licensee share is $11,250 times 0.70, or $7,875.
Answer: The referring brokerage receives $3,750. The stated licensee share is $7,875 before other deductions.
Commission inside seller net
A property sells for $500,000. The seller pays a 5% brokerage fee, a $310,000 mortgage payoff, an $8,000 buyer credit, and $6,000 in other seller costs.
- Commission is $500,000 times 0.05, or $25,000.
- Total seller debits are $25,000 plus $310,000 plus $8,000 plus $6,000, or $349,000.
Answer: Seller net before any other adjustment is $151,000.
A lease fee uses the stated rent term
A two-year lease states monthly rent of $2,500 throughout. The fee is 3% of the full scheduled rent for that term.
- The rent base is $2,500 x 24 = $60,000.
- The fee is $60,000 x 0.03 = $1,800.
- A fee based on one year or one month would be a different question.
Answer: The stated lease-fee calculation is $1,800. Actual earning and collection depend on the agreement.
A seller credit does not change the base by itself
A written fee is 4.5% of the gross $500,000 sale price. The seller also gives the buyer a $10,000 credit. No term reduces the fee base by that credit.
- The supplied commission base remains $500,000.
- $500,000 x 0.045 = $22,500.
- Using $490,000 would change the stated base without authority.
Answer: The commission is $22,500. The separate seller credit belongs in the seller ledger once.
A minimum is a floor, not an additional fee
The agreement sets the fee at the greater of 2% of a $200,000 sale price or $5,000. No separate added charge applies.
- The percentage result is $200,000 x 0.02 = $4,000.
- Compare $4,000 with $5,000 and use the greater amount.
Answer: The fee is $5,000, not $9,000.
The same flat charge changes with its position
A brokerage side is $15,000 and the licensee split is 70%. Compare a $450 charge deducted from that side before the split with a $450 charge deducted from the licensee's share afterward.
- Before the split: ($15,000 - $450) x 0.70 = $10,185.
- After the split: $15,000 x 0.70 - $450 = $10,050.
- The $135 difference comes from which share bears the charge.
Answer: The two stated arrangements produce $10,185 and $10,050. Read the actual sequence.
Find a price that leaves the target seller net
The seller wants $200,000 net. The only price-dependent cost is a fee of 5% of gross price. All other seller costs, including payoff, are fixed at $310,000. Find the price to the nearest cent.
- Let P be the price. P - 0.05P - $310,000 = $200,000.
- Then 0.95P = $510,000, so P = $510,000 / 0.95.
- Rounded price is $536,842.11. At that price the fee rounded to cents is $26,842.11; subtract it and the fixed $310,000 to reconcile the $200,000 net.
Answer: The required price on these assumptions is $536,842.11. The formula needs modification if other costs also depend on price.
A cap applies only to the share the contract names
A $16,000 brokerage side is split 75% to the licensee and 25% to the company. Only $3,000 remains under a cap on that company share. The supplied contract gives the licensee the excess and imposes no other deduction.
- The uncapped company share would be $16,000 x 0.25 = $4,000.
- The stated remaining cap limits that covered company share to $3,000.
- The licensee receives the rest: $16,000 - $3,000 = $13,000.
Answer: The company receives $3,000 and the licensee receives $13,000 under the stated cap terms.
Mistakes to avoid
- Multiply price by 5 for a 5% commission. Convert 5% to 0.05. Using 5 makes the result 100 times too large.
- Every commission uses sale price as its base. The agreement can use price, rent, a tier, a flat fee, or another defined base. Read the stated basis.
- A 70% licensee split applies to total transaction compensation. Use the amount named by the internal agreement or question. It may be the brokerage side after a specified deduction; it is not automatically the original sale price or full transaction fee.
- Add a 50% firm split and 70% licensee split to get 120%. Sequential percentages multiply. The licensee receives 0.50 times 0.70, or 35% of the original total in that simple chain.
- Apply the higher tier rate to the entire sale price. A marginal tier applies only to the amount within that tier unless the agreement expressly states otherwise.
- Subtract a seller-paid commission and its cooperating split twice. If the total fee already includes the cooperating allocation, subtract the total seller charge once.
- Payment source determines agency. Agency follows the brokerage relationship and designated agency, not merely whose funds contribute to compensation.
- A commission rate is fixed by Illinois law. Rates and fee structures are negotiable and belong in the written brokerage agreement.
- A purchase contract can casually change the brokerage fee. Rule 1450.770(j)-(k) requires a written amendment signed by the parties for the commission amount or payment-time change and prohibits using a real estate contract form to change previously agreed commission terms. A separate funding contribution does not necessarily change the agreed fee.
- Any referral payment is lawful if the math is correct. Licensing, sponsorship, Illinois compensation law, and federal RESPA restrictions can prohibit a mathematically correct payment.
- Round every intermediate split to the nearest dollar. Keep precision until the requested rounding step and follow the question's instruction. If the problem specifies separately rounded ledger amounts, reconcile those amounts rather than silently changing the convention.
- Commission splits deserve more study time than PSI's named math families. Know the supporting percentage skill, but prioritize seller net, buyer funds, prorations, transfer fees, PITI, equity, cap rate, LTV, and points.
- Referral fees always come after the licensee split. Use the stated referral base and who bears the deduction. The fee may come from the brokerage side before a split, from an individual share or another specified base.
- A cap means every charge disappears. Apply the cap only to the covered amount. Other charges and later transactions depend on the contract.
Check your understanding
These are original teaching questions, not recalled or predicted PSI questions. Answer first, then explain why the other choices fail.
1. A property sells for $360,000 and the stated brokerage fee is 4%. What is the fee?
- $40,000
- $144,000
- $1,440
- $14,400
Show answer and explanation
Answer: D. $14,400
$360,000 times 0.04 equals $14,400.
2. A $21,000 commission equals 5% of the fee base. What is the base?
- $420,000
- $105,000
- $400,000
- $1,050,000
Show answer and explanation
Answer: A. $420,000
$21,000 divided by 0.05 equals $420,000.
3. Total compensation is $30,000, the brokerage side is 50%, and the licensee receives 80% of that side. What is the licensee's gross share?
- $15,000
- $12,000
- $24,000
- $27,000
Show answer and explanation
Answer: B. $12,000
$30,000 times 0.50 equals $15,000; $15,000 times 0.80 equals $12,000.
4. Which statement about Illinois real estate commission rates is correct?
- The parties agree on fee terms while firms establish prices independently
- An MLS fixes every firm's consumer fee
- The state fixes one percentage
- Every cooperating brokerage split must be 50-50
Show answer and explanation
Answer: A. The parties agree on fee terms while firms establish prices independently
Use the stated independently agreed fee, not a standard percentage inferred from an example. The current written-agreement rule states the relevant basis or amount and payment time.
5. A seller is charged a $20,000 total brokerage fee that already includes a cooperating-broker allocation. How much should be deducted from seller net for that fee?
- $20,000
- $30,000
- $10,000
- $40,000
Show answer and explanation
Answer: A. $20,000
Deduct the total seller charge once. The internal or interbroker allocation does not create a second seller debit.
6. A fee is 5% of the first $300,000 and 3% of the excess. Price is $440,000. What is the fee?
- $19,200
- $22,000
- $13,200
- $17,600
Show answer and explanation
Answer: A. $19,200
$300,000 x 0.05 = $15,000;the excess $140,000 x 0.03 = $4,200. Add the tier fees to get $19,200.
7. A $15,000 brokerage side pays a 25% referral from that side, then splits the remainder 70% to the licensee. What is the licensee share?
- $3,750
- $7,875
- $11,250
- $10,500
Show answer and explanation
Answer: B. $7,875
The referral is $3,750, leaving $11,250. The licensee receives $11,250 x 0.70 = $7,875.
8. Rent is $2,500 monthly for 24 months. The fee is 3% of scheduled rent for the full term. What is the fee?
- $75
- $2,500
- $1,800
- $900
Show answer and explanation
Answer: C. $1,800
The rent base is $2,500 x 24 = $60,000. Multiply by 0.03 to get $1,800.
9. The stated fee is the greater of 2% of a $200,000 price or $5,000. No added charge applies. What is the fee?
- $4,000
- $9,000
- $5,000
- $10,000
Show answer and explanation
Answer: C. $5,000
The percentage fee is $4,000. The stated minimum is a floor, so use $5,000 rather than adding it.
10. A licensee receives 70% of a $15,000 side, then a $450 charge is deducted from that licensee share. What remains?
- $10,050
- $10,185
- $10,500
- $14,550
Show answer and explanation
Answer: A. $10,050
$15,000 x 0.70 = $10,500. Because the charge comes afterward, subtract $450 to get $10,050.
11. Under the stated terms, the buyer owes a $13,125 fee and $10,000 from the seller is credited toward it. No other contribution applies. What is the remaining buyer amount?
- $10,000
- $13,125
- $23,125
- $3,125
Show answer and explanation
Answer: D. $3,125
Subtract the credited $10,000 from the stated $13,125 obligation. The $3,125 result is arithmetic under the supplied terms, not approval of any financing or legal arrangement.
12. A $14,000 fee is based on $350,000. What is its percentage rate?
- 40%
- 0.04%
- 0.4%
- 4%
Show answer and explanation
Answer: D. 4%
$14,000/$350,000 = 0.04. Multiply by 100 to express that decimal as 4%.
Common questions
How do you calculate a real estate commission?
Multiply the stated compensation base by the stated rate in decimal form. A $425,000 sale with a 4.5% fee produces $425,000 times 0.045, or $19,125. Use the base named in the agreement or question and do not assume every fee is based on sale price.
How do you convert a commission percentage to a decimal?
Move the decimal point two places left or divide by 100. Thus 6% becomes 0.06, 4.5% becomes 0.045, and 0.75% becomes 0.0075. Multiplying by 4.5 instead of 0.045 makes the result 100 times too large.
How do you find the sale price from commission and rate?
Divide the commission by the decimal rate. If a 5% fee equals $18,500, the base is $18,500 divided by 0.05, or $370,000. Division is the reverse of the original base-times-rate relationship.
How do you calculate a real estate agent split?
First calculate the dollar amount available to the brokerage or side. Then multiply that amount by the licensee's stated split. If a side receives $12,000 and the sponsored licensee receives 70%, the licensee's gross share is $8,400 and the brokerage retains $3,600 before any other stated deduction. If the problem specifies a referral or other deduction before the internal split, adjust that base first.
Does a 50-50 co-broker split mean the agent receives half of total commission?
Not necessarily. A co-broker split divides compensation between brokerages. The sponsored licensee's internal split is a later calculation on that licensee's brokerage side. If total compensation is split 50-50 between firms and the licensee receives 70% of one side, the licensee receives 35% of the original total before other deductions.
Are real estate commission rates fixed in Illinois?
There is no standard percentage to insert into an exam problem. Firms must establish prices independently, and the consumer and brokerage agree on the fee terms. Rule 1450.770 requires the relevant written basis or amount and payment time. Negotiable does not mean a firm must accept any proposed fee. All rates and equal-split assumptions on this page are supplied facts, not required or typical prices.
Who may pay an Illinois sponsored licensee?
For licensed activity, the ordinary sponsored-licensee payment path is through the sponsoring broker. Section 10-5 also contains limited exceptions, including qualifying payments under a prior employment agreement for work performed while under the former sponsor. The math does not establish an exception or authorize new unsponsored work. See the compensation guide for the conditions; do not treat a client payment or any LLC as an automatic workaround.
How does commission affect seller net?
When the seller is charged the brokerage fee, subtract the calculated amount once from sale proceeds along with payoffs, seller credits, transfer charges, and other seller debits. Do not subtract the total fee and then subtract the same cooperating-broker portion a second time.
Are commission splits a named topic on the 2026 PSI calculation outline?
No. The current national calculation heading names seller net, buyer funds, prorations, transfer fees, PITI, equity, capitalization rate or rate of return, LTV, and points or origination fees. Basic commission math can still support seller-net and compensation questions, so learn it without displacing the named families.
Are these official Illinois real estate exam questions?
No. These are original teaching questions using the June 24, 2026 PSI outline and the cited primary provisions. They are not PSI items, a market-rate survey or a passing prediction. Each rate, split, deduction and cap is hypothetical. Actual compensation depends on the applicable agreements and law.
Does a referral fee come before or after the agent split?
Read its base and who bears it. A 25% referral from a $15,000 brokerage side is $3,750; splitting the remaining $11,250 at 70% gives the licensee $7,875. If the contract instead charges the full $3,750 to an already calculated $10,500 licensee share, the licensee has $6,750. Those are different arrangements.
How do minimum and flat fees change the formula?
Follow the wording. The greater of a percentage fee or a minimum requires a comparison, not addition. A separate flat charge is added or deducted only when specified. Its position before or after a split can change the result.
What is a tiered or blended commission rate?
A marginal tier applies its rate to the amount within that tier. Add the dollar fees from all tiers. The blended rate is that total fee divided by the full stated base, then expressed as a percentage. Do not take a simple average of the tier rates unless the amounts happen to justify it.
How do you calculate a leasing commission?
Convert the rent to the term named in the question, then apply the fee. For $2,500 monthly rent over 24 months, the scheduled rent is $60,000. A stated 3% fee on that total is $1,800. Do not replace the supplied basis with one month's rent or assume that every renewal earns another fee.
Is the answer to an agent-split question take-home pay?
Usually it is only the gross or post-specified-deduction share requested by the question. Taxes, other expenses and contract deductions may remain. The word net needs a defined scope; this page does not calculate an individual's tax liability.
Are referral fees always legal if the percentage is correct?
No. Illinois licensing and payment rules still apply. For a covered federally related mortgage settlement, Regulation X restricts referral payments and unearned fee splits. Its cooperative real estate brokerage exception is limited to parties acting in that brokerage capacity; it is not a general exception for mortgage-provider referrals. A correct multiplication does not approve a payment.
Can you reverse a commission formula when the rate is zero?
Dividing the fee by a zero rate does not determine a unique base. A 0% fee gives $0 across different bases. A valid reverse problem needs enough information, including a nonzero divisor for that division.
Keep practising
Your next practice step
Put real estate math into practice
Set up the calculation, keep the units consistent, and check the worked answer.
These web resources are free. The app has a separate free starter tier and optional paid full access.
Official sources and scope
Checked October 25, 2026. The official PSI outline, relevant Illinois payment text and FTC independent-pricing guidance were read. Other identified actual Illinois, NIST and CFPB readings are reused, with current indexed Regulation X passages crosschecked. These are hypothetical fee arrangements. The calculations do not establish a lawful referral, an earned commission or an actual market rate.
- PSI June 24, 2026: seller net and compensation outline
- NIST Guide to the SI: percent represents 0.01
- FTC: prices must be set independently
- 225 ILCS 454/10-5: payment routes and former-sponsor exception
- Rule 1450.770: written compensation terms and amendments
- 225 ILCS 454/15-40: payment does not determine agency
- CFPB Regulation X 1024.14: covered referrals and brokerage exception
- 225 ILCS 454/10-15: unlicensed work and referral restrictions
This is exam preparation, not advice for a specific transaction. State law and the applicable facts control. Our editorial and corrections process explains how to report an issue.