How we build and test the calculators
Every calculator is written from the primary source it cites and is checked by 113 automated tests that reproduce official worked examples. The full suite runs automatically on every change to the site's code.
Maintained by Sabrina Perez · Last reviewed
The process
- Primary source only. The rule is taken from the eCFR, the US Code, a DOL fact sheet, an IRS publication or the text of a court decision — never from another website.
- Formula in code, shown on the page. The exact formula the calculator runs is printed under it, with the section it implements.
- Tested against official examples. Where the DOL or the CFR publishes a worked example, a test reproduces it to the cent. Edge cases (minimum-wage floors, state exceptions, zero and boundary hours) get their own tests.
- Dated figures. Thresholds such as the $684/week salary level or the $2.13 tipped cash wage are stated with their effective date, because these numbers change and outdated ones circulate widely.
- Reviewed when rules change. Pages are re-checked at least once a year and whenever the DOL, IRS or a court changes a rule the site depends on.
Test coverage by calculator
| Calculator | Automated tests | Checked against |
|---|---|---|
| FLSA Overtime Calculator | 9 | DOL Fact Sheet #23; 29 CFR §778.110 |
| Fluctuating Workweek Calculator | 8 | DOL Fact Sheet #82; 29 CFR §778.114 |
| Blended Overtime Calculator | 12 | 29 CFR §778.115 worked example |
| Unpaid Overtime Back Pay Calculator | 14 | 29 U.S.C. §216(b), §255(a), §260 |
| Tip Credit Calculator | 13 | 29 U.S.C. §203(m); 29 CFR §531.50–§531.60; DOL Fact Sheet #15 |
| FMLA Eligibility Calculator | 13 | 29 U.S.C. §2611(2); 29 CFR §825.110–§825.111 |
| Exempt vs. Non-Exempt Wizard | 14 | 29 CFR Part 541 (2019 salary levels, restored May 2026) |
| California Daily Overtime Calculator | 13 | California Labor Code §510; DLSE Enforcement Manual |
| No Tax on Overtime Calculator | 17 | 26 U.S.C. §225; IRS Schedule 1-A Part III; IRS tax-year-2025 worked examples |
Your inputs stay on your device
Calculations run in your browser. Wages, hours and bonuses you enter are never sent to our servers. Analytics records only which calculator was used, never the numbers.
Corrections
Found a number that looks wrong? Email info@hrcalcs.com with the page and the source you are relying on. Confirmed errors are fixed, a test is added so the error cannot return, and the page notes what changed.
Limits
HRCalcs explains what published rules say and computes the arithmetic they prescribe. It is not legal, tax or payroll advice. Collective bargaining agreements, state and local law, and the facts of a specific job can change the answer.