The 15 NAB Math Calculations, Explained
Calculation questions, including occupancy rate, FLSA overtime, staffing hours, depreciation, and financial ratios, appear throughout 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 all 15 calculations, each with a worked example.
nhaexamprep.com · updated July 2026
The 15 calculations, each with a worked example
1. FLSA Overtime Pay
Overtime hours x (regular rate x 1.5)
Worked example: 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 (positive = unfavorable)
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: the wrong unit is always one of the choices
Exam writers build the distractor answers from the most common unit mistakes. If you compute the right number in the wrong unit, your answer will be one of the choices.
WATCH FOR THESE
- Percent vs decimal: the formula ends in x 100. Skipping that step is the most common error.
- 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: occupancy over 100%, payroll above revenue, or a negative rate means an inverted ratio.
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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