Overtime calculator for the US and Canada

The multiplier is applied to your regular rate, and the regular rate is an average: all the straight-time money you earned that week divided by all the hours you worked. Your posted hourly rate is only the same number when nothing else was paid. A shift differential, a night or weekend premium, a production or attendance bonus, a contractual safety bonus — anything you earn by working rather than as a gift — belongs in that average before the multiplier touches it.

Take that same 45-hour week under the plain weekly rule, five hours past 40, at $22.00 an hour, with 20 of those hours worked at night on a $1.50 differential.

A payroll run that applies 1.5× to the $22.00 base and pays the differential flat comes to $1,075.00. That is $1.67 short, every week, and nothing on the stub looks wrong: the hours are right, the differential is right, the multiplier is right. Only the rate the multiplier was applied to is wrong.

When a differential runs across every hour you work, the shortfall is exactly your overtime hours × 0.5 × the differential: on 5 overtime hours with a $1.50 differential all week, $3.75. When it covers only part of the week, as above, the differential is spread over all the hours first, so it lifts the regular rate by less and the shortfall shrinks with it. Non-discretionary bonuses work the same way and are allocated back to the weeks that earned them. A true gift, or a bonus that was never promised and whose payment and amount the employer decided entirely on its own near the end of the period, stays out of the rate.

A workweek is a fixed, recurring period of 168 hours. Your employer designates it, and it can start on any day of the week at any hour — Wednesday at 7 a.m. is as valid as Sunday at midnight. It does not have to match the calendar week, the pay period, or the schedule you actually work, and different departments can be on different ones. Once it is set it stays set; it can be changed if the new one is meant to be permanent, but not shuffled week to week to keep hours under a threshold.

It is the single most overlooked number in overtime, because it decides which hours are past the line. Seven consecutive 10-hour days, Wednesday through Tuesday, at $22.00 an hour:

Identical work, $330.00 apart. Nobody chooses their boundary after the fact; it is wherever the employer fixed it. But you cannot check a premium without knowing where it sits, and it is usually on the stub. If it is not, it is the first thing worth asking about. The calculator above assumes Sunday at midnight and says so; the app asks you once and then remembers.

Two workweeks are never averaged together, even when they arrive on one paycheck. Work 45 hours and then 35, and the first week owes five hours of premium while the second owes none. Eighty hours over two weeks is not a 40-hour average with nothing to pay.

The $55.00 between those rows is the whole reason the rule exists. Federal law makes a few narrow exceptions, each tied to a particular kind of employer or agreement: an 8-and-80 arrangement in hospitals and residential care that the employee accepts before the work is done (29 U.S.C. § 207(j)), work periods of 7 to 28 days for public-agency police and firefighters (§ 207(k)), and hours caps set in a union collective bargaining agreement (§ 207(b)). In Canada, several provinces allow hours to be averaged, each on its own terms — for example, a written agreement of no more than four weeks in British Columbia and Quebec, a written arrangement of up to 52 weeks in Alberta that the employer can require, and a permit from the employment standards office in Manitoba and Saskatchewan. In Ontario it takes an agreement that sets an averaging period of no more than four weeks under s. 22(2) of the Employment Standards Act.

The calculator carries every US state and Canadian province. These are the pages worth reading if your week has more than one threshold in it.