About TimeConverted – How We Calculate and Test

TimeConverted is a small reference site with calculators for working time: converting between hours-and-minutes and decimal hours, hours between two times, weekly time cards and overtime pay. It is run by TimeConverted.

The calculators are free and need no account. They run in your browser: what you type isn’t sent to us.

How we calculate

Exact arithmetic. Times are handled in whole seconds and minutes and money in whole cents (or pence), so results don’t pick up the rounding errors that decimals can cause. Pay is worked out line by line (regular, overtime, double time), each line is rounded to the cent, and the lines are added.
Totals before conversion. When several times are added, minutes are totalled first and converted to decimal hours once, so a total doesn’t drift by a hundredth.
Working shown. Each result lists the steps used to reach it. The steps are produced by the same code that produces the result, so they always match.
One set of overtime rules. The time card and the overtime calculator use the same overtime code, so the same week gives the same answer on both.

How we test

Every worked example published on the site is also an automated test, and the site isn’t published if any of them fail. Other tests check the rules directly: for example, that regular, overtime and double-time hours always add up to the hours worked, that regular hours never exceed the weekly overtime limit, that pay never goes down when hours go up, and that converting a time to decimal and back returns the same time.

The rules we follow

Converting time and adding up hours works the same everywhere. Overtime doesn’t: it is set by national or state law, collective agreements, awards and contracts. So the calculators have presets where a single public rule exists, and a Custom rule for everywhere else:

United States: the Fair Labor Standards Act (29 U.S.C. § 207 and 29 CFR part 778), plus California’s daily and seventh-day rules as published by the California Labor Commissioner.
Canada: the rules published by the governments of Canada, Ontario, Alberta and British Columbia.
Europe: France’s legal overtime rates (Service-Public.fr). For other European countries, the site explains the rules from official sources (the European Commission, the EU Court of Justice, the German, Spanish and Italian statutes, business.gov.nl and GOV.UK), and you enter your own rate, because most of them leave overtime pay to contracts and collective agreements.
Everywhere else: a Custom rule with your daily limit, weekly limit, higher-rate limits and rates. Money can be shown in US, Canadian or Australian dollars, euros, pounds, Swiss francs or rupees; the arithmetic is the same in any currency.

Each preset and each legal statement links to its source. Legal statements on the site are kept short. We review them periodically; the date is shown at the bottom of each calculator. The calculators give estimates for planning and record-keeping, not legal, tax or payroll advice. See the terms.

Corrections

If you find a wrong result, an unclear explanation or an out-of-date rule, please tell us at contact@timeconverted.com. Include the numbers you entered and what you expected. Confirmed errors are fixed, a test is added so they can’t come back, and the page’s review date is updated.