Methodology

How every calculator on this site is built, checked and kept up to date.

What the numbers mean

Unless a page says otherwise, pay figures are gross: before tax and other deductions. A calculator that estimates tax names its source and the tax year on its page.

Pay period conversions

To show one amount in several pay periods, the calculators convert to a yearly figure and divide back out: weekly = yearly ÷ 52, every two weeks = yearly ÷ 26, twice a month = yearly ÷ 24, monthly = yearly ÷ 12, hourly = yearly ÷ (hours per week × 52). Hours per week and weeks per year can be changed in the calculator.

Rounding

Calculations use full precision. Results are rounded to cents only when they’re displayed, so rounding never builds up inside a calculation.

How we test

• Each calculator has automated tests built from cases simple enough to verify by hand, such as a 5% raise on $60,000 giving $63,000.
• The worked examples and tables on each page are generated from the same calculation code and compared against hand-checked values when the page is built, so the text and the calculator can’t drift apart.
• Bad input (zero, negative or missing numbers) returns a clear message instead of a wrong answer.

Review

The publisher reviews each calculator before it goes live. A page shows a “Formula reviewed” date only after that review has happened.

Sources and updates

Calculators that rely on official rates, such as tax tables, cite the publication and year they use and are updated when those figures change. Corrections are recorded on the corrections page.

Limits

Calculators give estimates from the numbers you enter. They can’t know your full situation, so treat results as a starting point.