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Real estate proration math guide

Choose the day-count convention before counting days

The annual amount is only half the setup. The other half is the clock. A 360-day problem uses a 12-by-30 classroom year; a 365-day problem uses actual calendar days in a nonleap year. Write the method and the party responsible for closing day before finding a daily rate.

Last updated: August 1, 2026

What calculation do you need to make?

Short answer: Under a 360-day method, daily rate equals annual amount divided by 360 and each full month is treated as 30 days under the stated convention. Under a 365-day method, daily rate equals annual amount divided by 365 and the responsible period uses actual calendar days. A leap-year actual-day problem can require 366 when expressly directed. Before calculating, determine whether the item is accrued or prepaid, which party owns or benefits from each period, who gets closing day, and whether the question wants one party's share or the settlement entry. Prorated amount equals daily rate times responsible days. Accrued unpaid seller-period taxes commonly create a seller debit and buyer credit because the buyer will later pay the bill. A prepaid seller item can produce the opposite reimbursement. Keep daily-rate precision until final cents and never blend day counts from one method with the denominator from another.

Official section
National XI.B: Tax and Other Prorations
Broker weight
A named calculation within 7% of the national portion
Expected scored items
The current PSI broker outline assigns about 7 of 100 scored national items to Real Estate Math

Day-count and closing-day conventions come from the question, contract, applicable law, loan or lease documents, settlement instructions, and local practice. The 360-day and 365-day methods here are exam frameworks, not universal commands for every Illinois closing. Actual property-tax prorations can use agreed tax factors, prior bills, anticipated changes, exemptions, installment timing, and later reproration provisions. Federal Closing Disclosure rules govern presentation for covered transactions but do not create one universal substantive allocation between buyer and seller. This is exam preparation, not legal, tax, lending, or closing advice. Sources were checked through August 1, 2026.

How do you choose between 360-day and 365-day proration?

  1. Write the full-period amount, item type, due status, requested party, and requested settlement entry before any division or date counting begins.
  2. Circle the stated 360-day, 365-day, 366-day, or actual-calendar convention before counting dates on exam day.
  3. Determine whether seller or buyer is responsible for closing day and write the exact start and end dates.
  4. Divide the annual amount by the matching denominator while preserving daily-rate precision.
  5. Count responsible days using 30-day months for the 360 method or actual month lengths for the actual-day method.
  6. Multiply daily rate by responsible days and round the final money amount as instructed.
  7. Decide debit and credit from accrued or prepaid status and which party pays or benefits outside its period.
  8. Reverse-check the two periods, reject any mixed-method hybrid, and label the convention in the final answer.
Feature
Year denominator
360-day method
360
365 or actual-day method
365, or 366 if directed
Feature
Month assumption
360-day method
30 days
365 or actual-day method
Actual month length
Feature
Daily rate
360-day method
Annual / 360
365 or actual-day method
Annual / 365 or 366
Feature
Full month
360-day method
30 days
365 or actual-day method
28, 29, 30, or 31
Feature
Closing day
360-day method
Use stated allocation
365 or actual-day method
Use stated allocation
Feature
Seller days
360-day method
30-day convention
365 or actual-day method
Actual calendar count
Feature
Buyer days
360-day method
360 - seller days when valid
365 or actual-day method
Year days - seller days when valid
Feature
Prorated amount
360-day method
Daily rate x days
365 or actual-day method
Daily rate x days
Feature
Rounding
360-day method
Final cents unless directed
365 or actual-day method
Final cents unless directed
Feature
Main warning
360-day method
Do not use actual month lengths
365 or actual-day method
Do not assume every month has 30 days

Can you follow the calculation from facts to answer?

Use a 360-day proration

Scenario: Annual property tax is $7,200. A stated 360-day problem assigns 125 days to the seller. What is the seller share?

  1. $7,200 / 360 = $20 per day.
  2. $20 x 125 = $2,500.
  3. The problem supplies the day count, so no calendar recount is needed.

Answer: The seller's 360-day share is $2,500.

Use a 365-day proration

Scenario: Annual property tax is $7,300. A stated 365-day problem assigns 125 actual days to the seller. What is the seller share?

  1. $7,300 / 365 = $20 per day.
  2. $20 x 125 = $2,500.
  3. The matching denominator and actual-day count are explicit.

Answer: The seller's 365-day share is $2,500.

Compare methods with the same annual amount and days

Scenario: Annual rent is $18,000 and a classroom comparison uses 75 responsible days under each denominator. What are the two shares?

  1. 360-day share is $18,000 / 360 x 75 = $3,750.
  2. 365-day share is $18,000 / 365 x 75 = $3,698.63 after final rounding.
  3. The 360-day daily rate is larger because its denominator is smaller.

Answer: The shares are $3,750 under 360 days and $3,698.63 under 365 days.

Assign closing day before counting

Scenario: A nonleap-year actual-day problem closes April 10 and says the buyer owns on closing day. How many seller days run from January 1?

  1. Seller responsibility ends April 9.
  2. January 31 + February 28 + March 31 + April 9 = 99 days.
  3. If the seller owned through closing instead, the count would be 100.

Answer: The seller has 99 actual days under the stated allocation.

Handle an accrued tax entry

Scenario: A stated seller-period tax share is $3,240 and the buyer will later pay the unpaid bill. What simplified entry applies?

  1. The tax is accrued and unpaid for the seller's period.
  2. The buyer needs a credit because the buyer will later pay that share.
  3. The balanced opposite entry is a seller debit.

Answer: Debit seller and credit buyer $3,240.

Avoid premature daily-rate rounding

Scenario: Annual tax is $8,765 under a 365-day method, and the responsible period is 200 days. What is the share?

  1. $8,765 / 365 = $24.01369863 per day before rounding.
  2. $24.01369863 x 200 = $4,802.739726.
  3. Round the final amount to $4,802.74. Rounding the daily rate to $24.01 first would produce $4,802.00.

Answer: The 365-day prorated share is $4,802.74.

Which math errors cost the most points?

Trap
Use 360 because the question involves real estate.
Correction
Use the day-count convention expressly stated by the problem or transaction.
Trap
Divide by 365 but count 30-day months.
Correction
Match an actual-day denominator with actual calendar days.
Trap
Divide by 360 but count every 31st day.
Correction
Follow the stated 30-day-month convention consistently.
Trap
Use 365 automatically in a leap year.
Correction
Check whether the actual-day instructions require a 366-day denominator.
Trap
Count closing day for both parties.
Correction
Assign it once under the stated ownership convention.
Trap
Count closing day for neither party.
Correction
Ensure the two periods cover the intended year without a gap.
Trap
Choose debit and credit before identifying accrued or prepaid status.
Correction
Determine who paid, who benefited, and who will pay later first.
Trap
Treat an accrued seller tax as a seller credit.
Correction
If buyer will pay the seller-period bill later, debit seller and credit buyer.
Trap
Round the daily rate to cents immediately.
Correction
Carry precision and round the final prorated money unless instructed otherwise.
Trap
Assume both methods should produce the same amount.
Correction
Different denominators and day counts can create different contract allocations.
Trap
Use full-year minus seller days when periods do not cover the same full year.
Correction
Count the requested responsibility period directly when there are gaps or a different term.
Trap
Call a proration estimate the final property-tax liability.
Correction
A settlement allocation does not replace the taxing authority's bill and current contract terms.

Can you solve these original problems?

These questions are original study items aligned to the published outline. They are not copied, recalled, or predicted PSI questions.

1. Annual tax is $9,000. What is the daily rate under a 360-day method?

  1. $25
  2. $24.66
  3. $750
  4. $30
Show answer and explanation

Answer: $25

$9,000 / 360 = $25 per day.

2. Annual tax is $7,300. What is the daily rate under a 365-day method?

  1. $20
  2. $20.28
  3. $608.33
  4. $24
Show answer and explanation

Answer: $20

$7,300 / 365 = $20 per day.

3. A nonleap-year actual-day closing is April 10, and buyer owns on closing day. How many seller days run from January 1?

  1. 99 days
  2. 100 days
  3. 90 days
  4. 101 days
Show answer and explanation

Answer: 99 days

Count January 31, February 28, March 31, and April 1 through 9.

4. Who receives the credit for an accrued unpaid seller-period property tax that the buyer will pay later?

  1. Buyer
  2. Seller
  3. Listing broker
  4. Tax assessor
Show answer and explanation

Answer: Buyer

The buyer receives a credit and the seller receives the matching debit.

5. Which setup is internally consistent?

  1. Annual amount divided by 365 times actual calendar days
  2. Annual amount divided by 365 times 30-day months
  3. Annual amount divided by 360 times actual 31-day months
  4. Annual amount divided by 12 times 365
Show answer and explanation

Answer: Annual amount divided by 365 times actual calendar days

The denominator and day-count convention match.

Which numbers and formulas are easy to confuse?

Terms
360-day vs. 365-day method
Difference
The 360-day method uses 12 assumed 30-day months. The 365-day method uses actual nonleap calendar days.
Question cue
Commercial classroom year versus actual calendar year.
Terms
365-day vs. 366-day year
Difference
A 365 denominator fits a nonleap actual year. A 366 denominator can fit an expressly stated leap-year actual-day method.
Question cue
Ordinary year versus leap year.
Terms
Daily rate vs. day count
Difference
Daily rate comes from annual amount divided by the method denominator. Day count measures the responsible period.
Question cue
Dollars per day versus number of days.
Terms
Seller owns through closing vs. buyer owns on closing
Difference
The first includes closing day in seller time. The second assigns it to buyer time.
Question cue
Inclusive seller day versus exclusive seller day.
Terms
Accrued vs. prepaid
Difference
Accrued means incurred but not yet paid. Prepaid means paid before the benefit period is complete.
Question cue
Owed later versus paid already.
Terms
Prorated share vs. settlement entry
Difference
The share is the allocated amount. The entry identifies who is debited and credited.
Question cue
How much versus who pays whom.
Terms
Actual tax bill vs. estimated proration
Difference
The bill is issued under the taxing process. A closing proration can use an estimate or agreed factor before the bill is known.
Question cue
Government charge versus contract allocation.
Terms
Calendar count vs. date subtraction
Difference
A calendar count follows inclusive or exclusive responsibility. Raw date subtraction can omit the first or last day depending on convention.
Question cue
Ownership days versus elapsed intervals.
Terms
Final rounding vs. daily-rate rounding
Difference
Final rounding preserves intermediate precision. Daily-rate rounding can multiply a small error across many days.
Question cue
Round once versus compound rounding error.
Terms
Exam method vs. contract method
Difference
The exam uses the convention stated in the stem. A transaction uses current contract and settlement instructions.
Question cue
Question rule versus closing rule.

What does the outline expect you to calculate?

Topic
Proration purpose
What to know
Allocation, ownership period, benefit period, payment timing, closing, fair share, annual amount, prepaid item, accrued item, and settlement adjustment
Best exam move
Identify whose period is being allocated before doing day-count arithmetic.
Topic
Annual amount
What to know
Property tax, rent, insurance, association charge, interest, service contract, annual bill, known amount, estimated amount, and tax factor
Best exam move
Use the full-period amount supplied and label whether it is actual or estimated.
Topic
360-day year
What to know
Twelve months, 30-day month, 360 denominator, banker year, classroom method, daily rate, monthly shortcut, and instruction
Best exam move
Divide annual amount by 360 and use the matching 30-day-month count.
Topic
365-day year
What to know
Actual calendar, nonleap year, 365 denominator, month lengths, daily rate, actual days, January through December, and instruction
Best exam move
Divide by 365 and count the actual responsible calendar days.
Topic
366-day leap year
What to know
February 29, leap year, actual-year denominator, stated convention, calendar days, daily rate, and date check
Best exam move
Use 366 only when the actual-day convention or problem expressly requires it.
Topic
Daily rate
What to know
Annual amount, denominator, division, dollars per day, precision, rounding, recurring charge, and method label
Best exam move
Carry enough decimal precision until the final proration amount.
Topic
360-day count
What to know
Full 30-day month, partial month, day number, 31st, February, start date, end date, inclusive count, and convention
Best exam move
Follow the exact 30-day rule supplied rather than mixing actual month lengths.
Topic
Actual-day count
What to know
January 31, February 28 or 29, April 30, month table, cumulative days, inclusive day, exclusive day, and date range
Best exam move
Write each month's responsible days and add them before multiplying.
Topic
Closing-day allocation
What to know
Seller owns through closing, buyer owns on closing, day before closing, include, exclude, possession, contract convention, and responsibility
Best exam move
State which party receives closing day before counting either share.
Topic
Seller-day method
What to know
January 1, closing date, seller period, days elapsed, through closing, before closing, accrued amount, and subtraction check
Best exam move
Count only the seller's responsible period when finding the seller adjustment.
Topic
Buyer-day method
What to know
Day after seller period, year end, remaining days, buyer period, prepaid item, reimbursement, full year minus seller days, and check
Best exam move
Use total convention days minus seller days only when the periods cover the same full year without gaps or overlap.
Topic
Accrued item
What to know
Used but unpaid, property tax in arrears, rent earned, interest accrued, seller responsibility, buyer later pays, debit, and credit
Best exam move
Charge the party who incurred the unpaid share and credit the party who will bear the later payment.
Topic
Prepaid item
What to know
Paid in advance, insurance, rent, association fee, seller payment, buyer benefit, reimbursement, seller credit, and buyer debit
Best exam move
Reimburse the party who paid for the other party's post-closing benefit when the problem directs.
Topic
Debit and credit
What to know
Seller debit, seller credit, buyer debit, buyer credit, balanced entry, ledger, cash to close, seller net, and direction
Best exam move
Name both sides after calculating the amount rather than deciding direction from a memorized sign alone.
Topic
Method comparison
What to know
Same annual amount, 360 daily rate, 365 daily rate, different day counts, dollar difference, convention, estimate, and no hybrid
Best exam move
Calculate each method independently before comparing results.
Topic
Rounding
What to know
Daily rate, cents, intermediate digits, final amount, whole dollar, instruction, cumulative difference, and calculator memory
Best exam move
Round final money to cents unless the problem directs another rule.
Topic
Reverse check
What to know
Seller days plus buyer days, 360, 365, 366, full-period amount, two shares, daily rate, and reconciliation
Best exam move
Confirm the two responsibility periods cover the intended full period once, without a missing or double-counted day.
Topic
Illinois property-tax context
What to know
Tax year, paid in arrears, seller responsibility, closing, prior bill, estimate, factor, exemption change, reproration, and agreement
Best exam move
Use the stated tax amount and allocation without assuming a classroom result is a final Illinois tax bill.

How should you drill this calculation?

Session
Session 1
Focus
Choose the convention
Proof you are ready
Classify 30 stems as 360-day, 365-day, 366-day, actual-calendar, or insufficiently specified.
Session
Session 2
Focus
Calculate daily rates
Proof you are ready
Calculate and compare 25 annual amounts under 360 and 365 denominators without premature rounding.
Session
Session 3
Focus
Count responsibility days
Proof you are ready
Count 20 seller and buyer periods under stated closing-day allocations for both methods.
Session
Session 4
Focus
Post debits and credits
Proof you are ready
Classify 30 accrued and prepaid tax, rent, insurance, and association items by amount, debit, and credit.
Session
Session 5
Focus
Compare and reverse-check
Proof you are ready
Solve 20 paired-method comparisons and reconcile the two party periods to the full convention year.
Session
Session 6
Focus
Complete a mixed proration set
Proof you are ready
Score at least 90% and justify every denominator, date count, closing day, status, entry, precision choice, and qualifier.

Do not count recognition as mastery. Close the notes and explain the rule, apply it to a new fact pattern, and identify why each distractor fails.

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Questions students ask about 360-Day vs. 365-Day Real Estate Proration

What is the 360-day proration method?

A simplified 360-day method treats the year as 12 months of 30 days. The daily rate is the annual amount divided by 360. For a partial date span, count the responsible 30-day-month days under the convention stated in the question, then multiply by the daily rate. This is not automatically the same as prorating by whole months. A daily 360 calculation can include a partial 30-day month, while a monthly calculation may allocate only complete monthly periods under different instructions.

What is the 365-day proration method?

The 365-day method divides the annual amount by 365 and multiplies by the actual responsible calendar days stated or counted. In a leap year, use 366 only when the problem or governing convention calls for actual days in that leap year.

Which proration method should I use on the Illinois broker exam?

Use the method expressly supplied by the problem. The PSI outline tests prorations but does not make one classroom day-count convention universally controlling. Look for 360-day year, 365-day year, actual days, 30-day months, calendar method, or a direct instruction.

Why do 360-day and 365-day answers differ?

They use different daily rates and can use different day counts. Dividing the same annual amount by 360 produces a slightly larger daily rate than dividing by 365. A 30-day-month count can also differ from actual calendar days in February and 31-day months.

Who gets the closing day in a proration?

The party identified by the problem, contract, local practice, or settlement instruction. If the seller owns through closing, include closing day in the seller period. If the buyer owns on closing day, end the seller period the day before. Never assume without reading the stated convention.

How do you count days under a 360-day method?

Use the problem's 30-day-month convention. One common classroom count assigns 30 days to each full month and then adds the stated partial-month days. Dates on the 31st and end-of-February handling can follow specialized conventions, so use the exact instruction rather than inventing one.

How do you count days under a 365-day method?

Count actual calendar days in the responsible period, following the closing-day allocation. A quick cumulative-day table or month-by-month list reduces errors. Verify February and leap-year status before finalizing the count.

What is the debit and credit for accrued property tax?

When the seller owes the buyer for an accrued unpaid tax period that the buyer will later pay, the simplified entry is a seller debit and buyer credit. The direction follows who benefited from the period and who will pay the later bill, not merely which party brings cash to closing.

Should I round the daily proration rate?

Unless instructed otherwise, keep enough precision in the daily rate and round the final money result to cents. Rounding the daily rate too early can change the final amount across many days. Show the convention, count, and final rounding.

Are these official Illinois broker exam questions?

No. They are original calculations aligned to the PSI Illinois broker outline effective June 24, 2026. Current Illinois Department of Revenue property-tax guidance and current federal Closing Disclosure requirements were checked through August 1, 2026.

Primary sources

The current official outline controls the tested scope. Statutes, regulations, and official agency materials control when a general study rule and a jurisdiction-specific rule differ.

Editorial status

Checked against primary sources

The Pass Illinois editorial team last checked this guide on August 1, 2026. Every practice question is an original study item, and the source links above let you verify the rules that support the lesson.

Read our editorial and corrections process

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