How our estimates work
Smart Pay Tools publishes calculators and explanatory guides for planning and education. This page explains the assumptions behind the results so you can decide whether a tool fits your question.
Updated September 24, 2026
Formulas and units
Hourly pay calculations multiply a rate by hours. Time-and-a-half and double-time tools apply fixed 1.5× and 2× multipliers to the hours you enter in those categories. They do not determine which hours qualify. Pay-period conversions assume a steady rate and schedule; monthly estimates divide annual pay by 12.
Use decimal hours: 15 minutes is 0.25 hours, not 0.15. Amounts are displayed in U.S. dollars and rounded to two decimal places for readability. Intermediate arithmetic is not intentionally rounded at each step, so an employer's rounding practice can produce small differences.
Comparing scenarios
Each calculator can compare two sets of inputs. Scenario B begins as a copy of A; changing one does not change the other. Differences are calculated as B minus A using unrounded values, then displayed to the nearest cent. Compare matching periods and assumptions in both columns.
Weekly and biweekly annual projections assume 52 paid weeks at the same schedule. Monthly and hourly-to-salary tools let you enter paid weeks. Overtime, shift, and PTO results apply only to the hours entered and are not automatically projected over a year. Blank or invalid inputs hide results; a valid zero still produces a zero amount.
Taxes and eligibility
Most results are gross amounts before deductions. The overtime-after-tax tool instead applies one percentage supplied by you. It does not use tax brackets, payroll withholding tables, filing status, or the qualified overtime deduction to compute tax.
The site does not determine overtime exemption, leave payout rights, or an employer's legal regular rate. U.S. labor and tax references provide context, with state examples labeled. Other countries and special employment arrangements may use different rules.
Examples and sources
Worked examples use fictional rates and schedules and show the steps needed to reproduce the result. The calculator's default values are examples rather than recommendations. Guides link to government sources for legal and tax context; the worked arithmetic and planning scenarios are written for this site.
We label content update dates when the explanation is revised. A date is not a guarantee that a rule fits your circumstances. Follow the linked source for its scope, exceptions, and latest version.
Checking and correcting results
Examples should agree with the displayed formula. If a result seems wrong, first check units, the pay period, and whether the number is gross or net. An estimate using one rate cannot capture additional bonuses, deductions, or premiums unless the tool explicitly includes them.
To report an issue, send the page, fictional inputs, expected result, and the reason for the difference. This lets the owner check the arithmetic or explanation and correct it where needed. See contact and corrections.
Input handling and advertising
The calculator formulas run in your browser. The calculator code does not submit the entered numbers to a server. Analytics and advertising services operate separately; see the privacy policy for their data practices.
Advertising supports the free site and does not affect the formulas. For more about the project and its ownership, visit About Smart Pay Tools.