Pay periods and overtime

Biweekly Pay and Overtime: Where the Hours Belong

If you work 45 hours in week 1 and 35 hours in week 2 of a two-week pay period, you are owed overtime for 5 hours — the five hours above 40 in week 1. You are not owed nothing because the two weeks average to 40. Overtime is decided one workweek at a time, and the federal rule says averaging over two or more weeks is not permitted. The 35-hour week does not cancel the 45-hour week, and it does not borrow from it either. Everything below is the arithmetic for that, plus the two-rate case where overtime has to be calculated on a weighted average overtime rate rather than a single rate.

The short answer

That is the whole answer, and it holds whether you are paid weekly, biweekly or semi-monthly. The pay period is how often you get paid. The workweek is what overtime is measured against. They are two different clocks and only one of them decides the 40-hour line.

The rule is a workweek, not a pay period

The decisive sentence comes from the U.S. Department of Labor's Fact Sheet #23, which describes the workweek as “a fixed and regularly recurring period of 168 hours — seven consecutive 24-hour periods” and then states plainly: “Averaging of hours over two or more weeks is not permitted.” The same fact sheet says overtime is owed for hours worked “in excess of 40 in a workweek.”

The Department's electronic elaws adviser spells out why the averaging question never even arises: the workweek “does not have to coincide with the calendar week, but instead it may begin on any day of the week and at any hour of the day,” and once its start is fixed it stays fixed. So a biweekly paycheck is simply two workweeks paid on one cheque. Each is tested on its own 40-hour line.

Two consequences follow that catch people out:

1. A short week never refunds a long week. Week 2 at 35 hours produces no overtime and cannot be netted against week 1's five hours. The five hours are owed on their own.
2. A long week cannot be pre-paid by a short one. Working 50 hours in week 1 and 30 in week 2 does not create a 40-hour average; week 1 owes 10 hours at the premium rate regardless of what week 2 holds.
3. Moving the workweek start is allowed, but not casually. The elaws glossary permits a change to the beginning of the workweek only if it is “intended to be permanent and is not designed to evade the overtime requirements.” You cannot slide the boundary per pay period to swallow a long week.

What the calculation looks like in money

Using the two weeks above at a single illustrative rate of $18.00 an hour, so the shape of the pay is visible without a second variable in it. Overtime is paid at one and a half times the regular rate; the extra half is the premium.

Notice where the money went. Week 1's gross includes all 45 hours, five of them carrying the extra half. Week 2's gross is 35 hours at face value. Add them: $1,485.00 for the pay period. If someone had averaged the weeks and paid every hour at $18.00, the premium would have quietly disappeared — $45.00 of it in this example.

The two-rate week, and the weighted average overtime rate

The harder version of the question is what happens when a single workweek is worked at two different rates. You do not pick one rate and you do not pay the premium on the higher one. You compute a weighted average overtime rate — also called the blended overtime rate — from the week's actual earnings, then load the overtime hours on that blended figure.

The federal rule is in Fact Sheet #23: where an employee “works at two or more different types of work for which different straight-time rates have been established, the regular rate for that week is the weighted average of such rates. That is, the earnings from all such rates are added together and this total is then divided by the total number of hours worked at all jobs.” The regulation behind it, 29 CFR 778.115, says the same thing and describes the division as “total earnings … divided by the total number of hours worked at all jobs.”

California's Labor Commissioner states it in identical terms on the state side and works an example: the regular rate is the “weighted average” obtained by “dividing your total earnings for the workweek, including earnings during overtime hours, by the total hours worked during the workweek, including the overtime hours.” This is the one place on this page where the state and federal instructions line up word for word.

Worked example: 45 hours, two rates, one week

Here is the calculation done from scratch. Every input is labelled with where it came from, and the formula is printed so the arithmetic can be checked.

The two routes in step 4 give exactly the same number, which is the point of printing both: the half-time method adds the extra half to straight time already paid, and the 1.5× method pays the overtime hours in full. They agree at $901.44.

What it costs to use the wrong rate

Because the blended rate sits between the two rates, using either end of the range instead introduces a specific error on this week. Both are computed below.

Two dollars and forty-four cents does not sound like much for one week of a small shift differential. It is the same $2.44 every week the pattern repeats, and the blended rate has to be recomputed each week because the split between the two rates moves.

Where the state departs from the federal rule

The workweek rule above is federal and applies everywhere. Some states add a second, daily clock on top of it, and California is the clearest example. The state Labor Commissioner's overtime page sets out the general provisions: a nonexempt employee “shall not be employed more than eight hours in any workday or more than 40 hours in any workweek” without the premium, and the rates are “one and one-half times the employee's regular rate of pay for all hours worked in excess of eight hours up to and including 12 hours in any workday”, with “double the employee's regular rate of pay for all hours worked in excess of 12 hours in any workday.” There is a seventh-day rule as well: the first eight hours on the seventh consecutive day carry the one-and-a-half rate and hours beyond eight on that day carry double time.

That means the same 45-hour week can be attributed differently depending on how it was shaped, even though the weekly total is identical. Take 45 hours spread as 9, 8, 8, 8, 8, 4 across six days.

The one daily hour and the five weekly hours overlap, so they are not added together — an hour already paid a premium is not paid a second one. The shape of the week is what the daily clock sees and the weekly clock cannot. That is the whole difference: federal overtime counts only the weekly total; California overtime also counts the shape of each day. The exact stacking of daily and weekly premiums is governed by Labor Code section 510 and the applicable Wage Order, and this table shows the arithmetic rather than a conclusion about any particular schedule. States without a daily overtime rule follow the federal weekly test alone.

Where averaging does show up

There is one place the word “average” belongs, and it is not the number of hours. On the state side, California's Labor Commissioner notes that where an agreed regular workweek is shorter than 40 hours, that agreed figure is used to derive the regular rate — the page gives a 35-hour agreed week as the example. That is averaging a rate over the agreed regular hours; it does not authorise averaging worked hours across weeks to make overtime vanish. The workweek stays the unit of measurement either way.

Checking a biweekly stub against these rules

1. Split the stub back into workweeks. The dates printed for the pay period are not the workweeks unless the employer's workweek happens to start on that day. Find the fixed seven-day boundary your employer uses and put the hours back into their two buckets.
2. Test each bucket against 40, on its own. A 45 and a 35 give 5 overtime hours; two 40s give none; a 50 and a 30 give ten. The pair's average is never the answer.
3. If the stub shows a blended overtime rate, recompute it. Total the week's earnings at every rate, divide by the week's total hours, and compare to what the stub used. A blend that equals the lower rate usually means one rate was never brought into the calculation.
4. In a daily-overtime state, lay out each day before trusting the weekly figure. A week that totals 40 hours can still owe daily premiums if one day ran past the daily limit.
5. Remember the premium is half. If straight time for the week was already paid, the overtime line should be about half the blended rate times the overtime hours, not a full rate times those hours on top of pay that already covered them.
6. Keep the state's rules separate from the federal ones. A schedule that is fully compliant on the weekly test can still owe a daily premium in a state that has one, and a state rule never lowers the federal floor.

The sources behind every rule on this page

Each rule above is stated by a government source, and each is linked so the wording can be read in full.

• The workweek is “a fixed and regularly recurring period of 168 hours — seven consecutive 24-hour periods”, overtime is owed for hours “in excess of 40 in a workweek”, and “Averaging of hours over two or more weeks is not permitted” — U.S. Department of Labor, Wage and Hour Division, Fact Sheet #23. Official federal source.
• The weighted average of rates, where a week is worked at two or more rates, is “total earnings … divided by the total number of hours worked at all jobs” — 29 CFR 778.115. Official federal regulation.
• The workweek “may begin on any day of the week and at any hour of the day” and a change to it must be “intended to be permanent” — U.S. Department of Labor elaws overtime adviser, glossary entry for workweek. Official federal source.
• California's daily and weekly overtime rates, the seventh-day rule, and the state's worked weighted-average example — California Department of Industrial Relations, Labor Commissioner's Office, Overtime. Official state source.
• The state's statutory basis for daily and weekly overtime — California Labor Code section 510. Official state source.

Values that are illustration rather than law — the $18.00 and $22.00 rates, the 34 and 11 hour split, and the 9/8/8/8/8/4 day layout — are labelled as illustrative where they appear and are not attributable to any of the sources above. The rate of $18.98 and the money figures derived from it are arithmetic performed on those illustrative inputs using the formula printed in each step.

Last updated: 13 October 2026. Rules and quotations on this page are taken from the U.S. Department of Labor and the California Department of Industrial Relations at the pages linked above; the worked examples are calculated on the illustrative inputs shown, with the formula printed so each figure can be checked. This page explains how the rules are written, not how they apply to a particular employer or schedule.