15 Math Calculations for the NAB Exams, Explained
Occupancy rate, FLSA overtime, staffing hours, depreciation, and financial ratios are everyday numbers in running a nursing home, so they are worth being able to calculate for the NAB exams. The math itself is not hard. What trips candidates up is producing the right formula under time pressure and answering in the unit the question asked for. Here are 15 of them, each with a worked example.
nhaexamprep.com · updated September 2026
15 calculations, each with a worked example
1. FLSA Overtime Pay
Overtime hours x (regular rate x 1.5)
Worked example: $15.00 regular rate: 5 x ($15.00 x 1.5) = 5 x $22.50 = $112.50 for the 5 OT hours (plus 40 hrs straight time)
2. Occupancy Rate
Occupied beds / total beds x 100
Worked example: 108 of 120 beds: 108 / 120 = 90%
3. Cost Per Resident Day
Total operating costs / total resident days
Worked example: $1,200,000 / 8,000 days = $150 per resident day
4. Full-Time Equivalents (FTE)
Total hours worked per week / 40
Worked example: 4 staff x 8 hrs x 5 days = 160 hrs / 40 = 4.0 FTEs
5. Nursing HPPD
Total direct nursing hours / average daily census
Worked example: 480 direct-care hours for 120 residents = 4.0 HPPD
6. Straight-Line Depreciation
(Cost - salvage value) / useful life in years
Worked example: ($50,000 - $5,000) / 9 years = $5,000 per year
7. Profit Margin
(Revenue - expenses) / revenue x 100
Worked example: ($3.0M - $2.7M) / $3.0M = 10%
8. Budget Variance
Actual - budgeted (for an expense line, positive = unfavorable; for a revenue line, positive = favorable)
Worked example: $108,000 spent vs $100,000 budget = $8,000 unfavorable
9. Current Ratio
Current assets / current liabilities
Worked example: $500,000 / $250,000 = 2.0
10. Working Capital
Current assets - current liabilities
Worked example: $500,000 - $250,000 = $250,000
11. Payroll as % of Revenue
Total payroll / total revenue x 100
Worked example: $1.2M payroll / $2.0M revenue = 60%
12. Medication Error Rate
Errors / total opportunities x 100
Worked example: 10 errors / 500 opportunities = 2%
13. Weight Loss Percentage
(Usual - current weight) / usual weight x 100
Worked example: 180 lbs to 166.5 lbs: 13.5 / 180 = 7.5%
14. Staff Turnover Rate
Departures / average headcount x 100
Worked example: 18 departures / 60 average staff = 30%
15. Medicare Part A SNF Days
1-20 full / 21-100 coinsurance / 101+ exhausted
Worked example: Day 8 = covered. Day 45 = coinsurance. Day 101 = exhausted.
Unit traps: answer in the unit the question asks for
A right number in the wrong unit is still a wrong answer, and on a multiple-choice question it may be sitting among the choices. Check that your answer is in the unit the question asks for.
WATCH FOR THESE
- Percent vs decimal: the formula ends in x 100. Skipping that step is an easy error to make.
- Percent vs amount: profit margin is a percent, profit is dollars. Decide which is asked.
- Rate vs dollars: current ratio is a number (2.0), working capital is dollars. Same inputs, different question.
- Per year vs per day: depreciation is annual, cost per resident day is daily. Answer in the unit named.
- Right beds: use exactly the beds the question gives you (occupied, licensed, or available).
- Right days: cost per resident day divides by resident days (days of care), not residents or beds.
- Sanity check: an occupancy rate over 100% means something is off, often an upside-down ratio or the wrong beds or days.
Reading formulas is not the same as producing them
NHA Exam Prep works every one of these calculations into NAB-style questions, with numbers that change on every serve so you learn the method, not the answer key. The printable NAB Math Formula Sheet, which adds a self-quiz and a memorize-cold table to everything on this page, is free: download the PDF. Subscribers also get it delivered by email with their welcome message.
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