Overtime Calculation: By Day or by Week?

This overtime calculator estimates weekly overtime hours by comparing the hours you enter with a weekly threshold; it does not determine whether a particular worker is legally entitled to overtime. Enter total hours worked and the threshold that applies to you to see hours above it, alongside the hours at or below it.

Formula

For this simple weekly calculator, overtime hours are the greater of zero or total hours worked minus the weekly threshold. The regular-hours result is the lesser of total hours worked or the threshold.

• H = total hours worked during the week, in hours.
• T = the weekly threshold entered, in hours.
• O = hours above the threshold, in hours: O = max(0, H − T).
• R = hours at or below the threshold, in hours: R = min(H, T).

The threshold is an input, not a claim that one rule applies everywhere. The calculator uses hours only; it does not calculate wages, overtime premiums, daily overtime, exemptions, or special schedules.

Worked Example

Using the defaults, total hours are H = 45 hours and the weekly threshold is T = 40 hours.

1. Overtime hours: max(0, 45 − 40) = 5.00 hours.
2. Hours at or below the threshold: min(45, 40) = 40.00 hours.

The results add up to the entered total: 5 + 40 = 45 hours. The decimal places are a display choice; they do not mean that every employer records time to hundredths of an hour.

Is Overtime Calculated by Day or by Week?

There is no universal answer: it depends on the law and work arrangement that apply. In the United States, the general federal Fair Labor Standards Act (FLSA) rule for covered, nonexempt employees is overtime pay for hours worked over 40 in a fixed, recurring workweek. It is generally calculated week by week, not by averaging hours across several weeks. Some state or local rules provide additional daily overtime protections, so an employee may need to check both federal and applicable local requirements.

For example, under the basic federal weekly calculation, an employee who works 45 hours in one workweek has five hours over 40. An employee who works 35 hours one week and 45 the next does not simply average those weeks to 40: each workweek is considered separately under the federal rule. The calculator illustrates the arithmetic only; eligibility, the legally counted workweek, and other applicable rules must be established separately.

Other countries and jurisdictions may use daily limits, weekly limits, or a combination. Do not assume that a 40-hour week or a particular daily cutoff applies where you work.

How a Workweek and Workday Are Defined

Under the FLSA, a workweek is a fixed and regularly recurring period of 168 hours—seven consecutive 24-hour periods. It may start on any day and at any hour, and it need not match a calendar week or payroll period. Once established, it is generally treated as its own unit for overtime calculations; hours from separate workweeks are not combined to erase overtime in one of them.

A workday is not interchangeable with a workweek. Daily overtime rules may apply under state law, a contract, or another applicable arrangement even where federal law does not generally require overtime merely for exceeding eight hours in a day. A long shift can therefore raise different questions from a long workweek. Confirm the governing jurisdiction and rule rather than relying on a generic calculator.

What Hours Count and Who Is Covered?

The hours entered should represent hours worked in the relevant week, not simply the number of hours shown on a schedule. Under federal rules, work an employer requires or allows can count even if it was not scheduled. Depending on the circumstances, this may include work before or after a shift, required training, or certain waiting time. Paid leave, holidays, and other paid nonwork time do not automatically count as hours worked for federal overtime purposes.

Federal overtime rights also depend on coverage and employee classification. Many employees are covered and nonexempt, but some jobs or workers may be exempt under specific legal tests. A job title or salary alone does not necessarily settle exemption status. The calculator cannot determine classification; consult applicable labor-agency guidance or a qualified adviser if the facts are unclear.

Common Calculation Mistakes

• Averaging separate weeks: A busy week cannot generally be offset by a shorter week for federal FLSA overtime purposes.
• Using the payroll period as the workweek: A two-week pay period does not, by itself, turn two weeks into one overtime calculation period.
• Counting scheduled rather than actual work: Record all hours worked, including qualifying work outside the scheduled shift.
• Assuming daily and weekly rules are identical: A state or local daily rule may add overtime requirements beyond the federal weekly rule.
• Treating the result as a pay amount: This tool returns hours only. Pay calculations can depend on the regular rate, applicable premium rules, and other facts.

Keep a clear record of start and end times, unpaid meal periods, and work performed outside scheduled hours. If a result seems wrong, compare the time record with the employer’s stated workweek and check the relevant jurisdiction’s rules.

Frequently Asked Questions

Is overtime based on 40 hours in one week or two weeks?
For covered, nonexempt employees under the general federal FLSA rule, the threshold is assessed in each fixed workweek. A two-week payroll period does not permit averaging the hours across both weeks.

Does working more than eight hours in a day automatically mean overtime?
Not under the general federal rule by itself. Daily overtime may be required under state or local law or another applicable arrangement, so check the rules where the work is performed.

Do vacation or holiday hours count toward weekly overtime?
Paid leave and holiday pay are not automatically hours worked for federal overtime calculations. The treatment can differ under a policy, agreement, or local law.

Can overtime be calculated from a monthly or biweekly total?
A payroll period may be longer than the legal workweek, but the federal weekly calculation is not replaced by a monthly or biweekly average. Identify the established workweek and evaluate each one separately.

Does this calculator tell me how much overtime pay I am owed?
No. It estimates hours above the threshold you enter. It does not assess coverage, exemptions, local rules, the correct pay rate, or the amount owed.

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in hours | Hours worked this week | h | 45 | 0
in threshold | Weekly overtime threshold | h | 40 | 0
out overtime | Hours above weekly threshold | h | max(0, hours - threshold) | 2
out regular | Hours at or below threshold | h | min(hours, threshold) | 2