Real Estate Exam Math — Every Formula You Need (Worked Examples)
Math is where most candidates lose the real estate exam. Not because the math is hard — it isn't. It's seventh-grade arithmetic dressed up in adult clothes. People fail because they freeze, can't remember which number goes on top, and waste twelve minutes on a question that should take ninety seconds.
This guide fixes that. Every formula you need. Every calculation type that shows up on the salesperson and broker exams. Worked numbers. No fluff. By the end you'll have a cheat sheet in your head and a process you can run on autopilot.
The T-Method — Your Backbone for Almost Every Problem
If you remember nothing else, remember the T.
Part
-------
Whole | Rate
- Part = Whole × Rate
- Whole = Part ÷ Rate
- Rate = Part ÷ Whole
Cover up what you're solving for. The other two tell you what to do. Commission, taxes, interest, profit percentages, area conversions — they all collapse into the T. Master this and you've already won half the math section.
Commission Problems
Commission is the most common math question on the exam. Expect at least three.
Problem 1 — Basic Commission
A house sells for $425,000 at a 6% total commission. The listing broker and selling broker split 50/50. The listing agent gets 60% of their broker's share. What does the agent earn?
- Total commission: $425,000 × 0.06 = $25,500
- Listing broker's share: $25,500 × 0.50 = $12,750
- Listing agent's share: $12,750 × 0.60 = $7,650
Problem 2 — Back-Solving the Rate
You sold a property for $312,000 and your office collected $18,720 in commission. What was the commission rate?
- Rate = Part ÷ Whole = $18,720 ÷ $312,000 = 0.06 or 6%
Problem 3 — Back-Solving the Sale Price
A broker collected $14,400 at a 4.5% commission rate. What did the property sell for?
- Whole = Part ÷ Rate = $14,400 ÷ 0.045 = $320,000
One legal note before you move on: under Section 1 of the Sherman Antitrust Act of 1890, brokers cannot agree with competing brokers to fix commission rates. Commission is always negotiable between broker and client. The exam loves testing this — math problems sometimes hide a Sherman Act trap in the wording.
Area and Square Footage
Area shows up in lot questions, building questions, and price-per-square-foot questions.
Core formulas
- Rectangle: Length × Width
- Triangle: (Base × Height) ÷ 2
- Acre: 43,560 square feet
- Section: 640 acres = 1 square mile
- Township: 36 sections
Problem 4 — Lot Size
A rectangular lot measures 75 feet wide by 120 feet deep. How many square feet? What fraction of an acre?
- Area: 75 × 120 = 9,000 sq ft
- Acreage: 9,000 ÷ 43,560 = 0.2066 acres (just over one-fifth)
Problem 5 — Triangular Parcel
A triangular lot has a base of 80 feet and a height of 60 feet. Find the area.
- Area: (80 × 60) ÷ 2 = 2,400 sq ft
Problem 6 — Price Per Square Foot
A 2,100 sq ft house sold for $367,500. What was the price per square foot?
- $367,500 ÷ 2,100 = $175 per sq ft
Proration at Closing
Proration is the math of splitting bills at closing — taxes, insurance, HOA dues, rent. RESPA (the Real Estate Settlement Procedures Act, 12 U.S.C. §§ 2601–2617) requires these amounts to show up on the closing disclosure so the buyer can see exactly what they're paying. The settlement agent calculates them, but you need to know how on the exam.
Two methods exist:
- Statutory year (360 days): 12 months × 30 days. Also called the banker's year.
- Calendar year (365 days): Real days.
Your state will test one or both. Read the question carefully.
Problem 7 — 365-Day Proration (Taxes Paid in Arrears)
Annual property tax is $4,380. Closing date is June 15. Seller pays through the day before closing. Use the 365-day method. What does the seller owe?
- Daily rate: $4,380 ÷ 365 = $12.00/day
- Days seller owned (Jan 1 – June 14): 31 + 28 + 31 + 30 + 31 + 14 = 165 days
- Seller's debit: 165 × $12.00 = $1,980
Problem 8 — 360-Day Proration
Same numbers, banker's year.
- Daily rate: $4,380 ÷ 360 = $12.1667/day
- Days: 5 months × 30 + 14 = 164 days
- Seller's debit: 164 × $12.1667 = $1,995.33
Watch the wording. "Through the day of closing" means the seller pays one more day. "Up to the day of closing" means they stop the day before. Read it twice.
Loan-to-Value (LTV)
LTV is the loan amount divided by the property value (or sale price, whichever is lower).
LTV = Loan ÷ Value
Problem 9 — Standard LTV
Home costs $350,000. Down payment is $52,500. What's the LTV?
- Loan amount: $350,000 − $52,500 = $297,500
- LTV: $297,500 ÷ $350,000 = 0.85 or 85%
Anything over 80% typically triggers private mortgage insurance (PMI) on conventional loans. The Truth in Lending Act (TILA, Pub. L. 90-321) and Regulation Z (12 CFR 1026) require lenders to disclose the APR, finance charge, and total payments in standardized form so the borrower can compare loans on an apples-to-apples basis. Expect a TILA disclosure question paired with LTV math.
Discount Points and Origination Fees
One point = 1% of the loan amount (not the purchase price — exam trap).
Problem 10 — Cost of Points
Loan amount $320,000. Borrower pays 2 discount points plus a 1% origination fee. What's the total upfront cost?
- 2 discount points: $320,000 × 0.02 = $6,400
- 1% origination: $320,000 × 0.01 = $3,200
- Total: $9,600
Discount points are prepaid interest that buy down the rate. Origination fees are the lender's processing charge. Both must appear on the Loan Estimate and Closing Disclosure under Regulation Z and RESPA.
Capitalization Rate (Cap Rate)
Cap rate is how investors compare income properties. Memorize the IRV triangle:
I (NOI)
---------
R | V
- Value = Income ÷ Rate
- Income = Value × Rate
- Rate = Income ÷ Value
NOI = Net Operating Income = gross income − operating expenses. It does not include debt service or income tax.
Problem 11 — Solving for Cap Rate
A duplex generates $48,000 NOI annually and sold for $600,000. What's the cap rate?
- Cap rate: $48,000 ÷ $600,000 = 0.08 or 8%
Problem 12 — Solving for Value
An investor wants a 7.5% cap rate. A property produces $60,000 NOI. What's the maximum the investor should pay?
- Value: $60,000 ÷ 0.075 = $800,000
Higher cap rate = lower price = higher risk. Lower cap rate = higher price = perceived stability. That intuition saves you on at least one exam question.
Gross Rent Multiplier (GRM)
GRM is a quick-and-dirty valuation tool. It uses gross rent, not net.
GRM = Sale Price ÷ Gross Rent
Watch whether the problem uses monthly or annual rent — they'll trip you up.
Problem 13 — Monthly GRM
A rental house sold for $240,000. Monthly rent is $1,600. What's the monthly GRM?
- $240,000 ÷ $1,600 = 150
Problem 14 — Estimating Value with GRM
A comparable property has a monthly GRM of 145. The subject property rents for $2,100/month. Estimated value?
- $2,100 × 145 = $304,500
Property Tax — The Mill Rate
A mill = $1 per $1,000 of assessed value. Or $0.001 per dollar. Same thing.
Annual tax = (Assessed Value ÷ 1,000) × Mill Rate
Problem 15 — Mill Calculation
Assessed value is $280,000. Tax rate is 22 mills. What's the annual tax?
- $280,000 ÷ 1,000 = 280
- 280 × 22 = $6,160
Some states quote the rate as a percentage of assessed value instead — 22 mills = 2.2% — same answer, just different form.
Qualifying Ratios
Lenders use two ratios to decide if a borrower can afford a loan:
- Front-end (housing) ratio: PITI ÷ gross monthly income. Typical max: 28%.
- Back-end (total debt) ratio: (PITI + all other debt) ÷ gross monthly income. Typical max: 36% (conventional) or 43% (qualified mortgage rule).
PITI = Principal, Interest, Taxes, Insurance.
Problem 16 — Maximum Housing Payment
Borrower earns $7,200/month gross. Has a $400 car payment and $250 student loan payment. Lender uses 28% front-end and 36% back-end. What's the maximum PITI they qualify for?
- Front-end cap: $7,200 × 0.28 = $2,016
- Back-end cap: $7,200 × 0.36 = $2,592
- Available for housing under back-end: $2,592 − $650 = $1,942
- Maximum PITI: the lower of the two = $1,942
Quick legal pairing: the Equal Credit Opportunity Act (ECOA, 15 U.S.C. § 1691) prohibits a lender from discriminating in any aspect of a credit transaction based on race, color, religion, national origin, sex, marital status, age, or receipt of public assistance. The ratios apply to the income — not the borrower's demographics. Income from alimony, child support, Social Security, or part-time work must be counted. The exam will absolutely test this overlap.
Profit, Loss, and Percentage Change
% Change = (New − Old) ÷ Old
Problem 17 — Profit Percentage
Investor bought a flip for $185,000, put $22,000 into it, sold for $260,000. What's the profit percentage on total cost?
- Total cost: $185,000 + $22,000 = $207,000
- Profit: $260,000 − $207,000 = $53,000
- Profit %: $53,000 ÷ $207,000 = 0.256 or 25.6%
Problem 18 — Appreciation
A home was purchased for $310,000 four years ago. It's now worth $372,000. What's the total appreciation percentage?
- Gain: $372,000 − $310,000 = $62,000
- Appreciation: $62,000 ÷ $310,000 = 0.20 or 20%
Simple Interest
Interest = Principal × Rate × Time
Time is in years (or fractions of a year).
Problem 19 — Annual Interest
A $245,000 loan at 6.5% interest. How much interest in the first year?
- $245,000 × 0.065 × 1 = $15,925
Problem 20 — Monthly Interest
Same loan. How much of the first monthly payment goes to interest?
- $15,925 ÷ 12 = $1,327.08
That's why early mortgage payments are mostly interest — the principal balance is huge.
Equity
Equity = Market Value − Mortgage Balance
Problem 21 — Calculating Equity
Home worth $475,000. Current mortgage balance $312,000. Equity?
- $475,000 − $312,000 = $163,000
Down Payment Problems
Problem 22 — Working Backwards from Down Payment
A buyer puts $84,000 down, which is 20% of the purchase price. What's the sale price?
- $84,000 ÷ 0.20 = $420,000
Closing Cost Splits and Transfer Taxes
Transfer tax (sometimes called documentary stamps or deed tax) varies by state but is usually quoted per $100 or per $500 of sale price.
Problem 23 — Transfer Tax
State charges $0.70 per $100 of sale price. Property sells for $385,000. What's the transfer tax?
- $385,000 ÷ 100 = 3,850
- 3,850 × $0.70 = $2,695
The Exam Strategy That Actually Works
Here's the process. Use it on every math question.
- Read the whole problem before touching the calculator. Underline what they're asking for. Half of all wrong answers come from solving for the wrong unknown.
- Write down what you know in dollar/percentage form. Convert percentages to decimals before plugging in.
- Draw the T (or IRV). Cover what you need. Read what's left.
- Check units. Monthly vs annual. Loan amount vs sale price. Days the seller owned vs days they didn't.
- Sanity check the answer. If a commission of $250,000 falls out, you multiplied somewhere you should have divided.
Pick a multiple-choice answer that's mathematically possible. If three answers are within $50 of each other and one is wildly different, the outlier is almost always a distractor.
The Federal Law You Need Alongside the Math
The math doesn't live in a vacuum. Three federal statutes show up wrapped around calculation questions constantly:
- RESPA (1974, 12 U.S.C. § 2601): Requires standardized closing disclosures, prohibits kickbacks under Section 8, governs escrow account math.
- TILA (1968, Regulation Z): Forces uniform disclosure of APR, finance charges, and total of payments. Gives a three-business-day right of rescission on most refinances and HELOCs secured by a principal dwelling.
- ECOA (1974, Regulation B): Prohibits discrimination in any credit transaction. The lender's qualifying ratios must be applied identically to all applicants.
Pair these with the Fair Housing Act (Title VIII of the Civil Rights Act of 1968, as amended in 1974 and 1988) and you've covered the legal infrastructure that surrounds every dollar figure on the closing table.
Your Cheat Sheet, One More Time
- T-Method: Part = Whole × Rate
- IRV: Value = Income ÷ Rate
- Acre: 43,560 sq ft
- Mill: $1 per $1,000 of value
- LTV: Loan ÷ Value
- GRM: Price ÷ Gross Rent
- PITI ratios: 28% front-end, 36% back-end
- One point: 1% of the loan amount
- Simple interest: P × R × T
Tape that to your bathroom mirror for a week. By exam day it'll be muscle memory.
Keep Going
Math is a quarter of the exam. The other three-quarters is law, contracts, agency, financing, and property rights. If you want every formula, statute, and concept in one place — built around the same plain-English, no-BS style as this guide — grab the National Real Estate Master Guide at studystack.org. It's the same playbook thousands of candidates have used to pass on the first try. Stop guessing what's on the test. Start knowing.
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