Overtime Hours Calculator

What overtime hours really mean

Overtime is usually discussed as a pay concept, but the foundation of overtime is actually an hours concept. Before anyone can apply a pay rate multiplier, they must decide which of your worked hours are considered “regular time” and which are considered “overtime time.” That split is created by rules: daily thresholds, weekly thresholds, tiered thresholds (often called double time), special rules for certain days, and rounding rules that turn real clock events into payroll-friendly numbers.

This overtime hours calculator is built around that idea. It focuses on the part that is hardest to do consistently by hand: taking real shifts, subtracting breaks correctly, handling overnight work, then applying the overtime rules you choose so you end up with a clear breakdown. Once you have your overtime hours, you can use them for planning, budgeting, verifying a timesheet, or simply understanding your workload.

Regular hours vs overtime hours

Regular hours are the hours that fall within your normal limits. Overtime hours are the hours that exceed those limits. The tricky part is that “normal limits” are not universal. In some contexts, overtime is triggered after working more than a set number of hours in one day (for example, over 8 hours). In other contexts, overtime is triggered only after exceeding a weekly total (for example, over 40 hours). Some policies combine both daily and weekly overtime. Others choose only one. Some apply a second, higher tier after a larger threshold (often over 12 hours in a day), commonly referred to as double time.

Because there are many valid policies, this tool does not assume a single “correct” approach. Instead, it gives you clear switches: you can enable daily overtime, weekly overtime, a double time tier, and you can choose how daily and weekly overtime interact so the totals match the way your work is counted.

Start and end times are only the beginning

The simplest version of time calculation is “end time minus start time.” That gives you gross shift time. Real worked time often differs because of breaks. Many workplaces treat meal breaks as unpaid, while certain rest breaks may be paid. Your own situation might include a combination. If you subtract breaks incorrectly, everything downstream breaks too: your total hours are wrong, your overtime split is wrong, and your weekly totals drift in a way that is hard to notice until you compare against an official record.

The calculator makes break handling explicit. You can enter break minutes per shift, and you can choose whether those minutes should be subtracted (unpaid) or left in the counted hours (paid). If your policy is more complex, the Timesheet tab helps because you can treat different shifts differently by entering different break values in different rows.

Overnight shifts: the most common manual error

Overnight shifts are a common source of “negative time” mistakes. If a shift begins at 22:00 and ends at 06:00, a simple subtraction produces an end time that appears earlier than the start time. The shift is still valid. The fix is to treat the end time as occurring on the next day for that shift entry. When you mark a shift as overnight, this calculator uses that rule automatically.

Overnight work can also interact with overtime in policy-specific ways. Some systems assign the shift to the day it started. Others assign it to the day it ended. Still others split it across two dates. This calculator keeps overnight shifts as single entries for clarity. If your official system splits shifts by date, you can do the same by adding two rows in the Timesheet tab that share the overnight window.

Daily overtime and tiered overtime

Daily overtime is conceptually simple: you earn regular hours up to a daily threshold, and the excess becomes overtime. If you enable a double time tier, the day is split into three parts: regular hours (up to the daily threshold), overtime hours (between the daily threshold and the double time threshold), and double time hours (above the double time threshold). This is especially helpful for long shifts, emergency coverage, or industries where extended days are common.

A key detail is that daily overtime should usually apply to the day’s total hours, not to each individual shift entry. If you work a split shift, you may have two entries that are each under the daily threshold, but together they exceed it. That is why the Timesheet tab totals hours by date first and only then applies the daily tiers.

Weekly overtime and why “week start” matters

Weekly overtime depends on how your week is defined. Many places use a Monday-to-Sunday week, but some use Sunday-to-Saturday or Saturday-to-Friday. If you track a pay period that doesn’t match the payroll week start, your weekly overtime calculation can be shifted by one or two days, which can make your estimate disagree with payroll even if the hours are correct.

This calculator lets you set a week start day so weekly totals are bucketed correctly. When weekly overtime is enabled, the tool groups your timesheet rows into week buckets based on that start day, totals each bucket, then applies the weekly threshold. This approach is easy to reason about and keeps the logic consistent when you export or compare results.

How daily and weekly overtime interact

The most confusing part of overtime is how daily overtime and weekly overtime are combined. Policies differ, but there are a few common patterns:

• Daily only: Overtime is purely a daily concept. Weekly totals are informational.
• Weekly only: Overtime is purely a weekly concept. Long days don’t matter unless they push the week over the threshold.
• Both, without double-counting: Daily overtime is counted first. Weekly overtime is then calculated on remaining hours so the same hour is not counted twice.
• Use the larger result: Some planning approaches take the higher of daily-based overtime and weekly-based overtime as an estimate.

The “Both (weekly OT after daily OT)” option in the Rules tab is designed to avoid double-counting. Conceptually, you can think of it like this: daily overtime identifies certain hours as overtime. Weekly overtime then applies only if, after that daily overtime is accounted for, the week still exceeds the weekly threshold. The result is a cleaner split between regular and overtime when both rules exist.

Rounding rules: small minutes, big impact

Many payroll systems apply rounding. A few minutes on one shift rarely matters, but over a full pay period, small differences can add up. Rounding also affects overtime boundaries: rounding can push a day above or below a threshold, which changes which hours are considered overtime.

This calculator includes a rounding setting and a rounding basis. If you round net minutes, the tool calculates net time first and then rounds it. If you round gross minutes, the tool rounds the gross time window before subtracting breaks. Both approaches can be valid depending on how time is captured. If you are comparing against an official system, match the approach that best reflects how their system works.

Daily tab: quick checks for one shift

The Daily Overtime tab is best when you want a fast answer for a single shift. Enter start time, end time, break minutes, and whether the shift is overnight. The calculator returns net worked time and then splits it into regular and overtime tiers based on your rules. If you enable “Add to timesheet,” you can build a running set of shifts without leaving the tab, then switch to the Timesheet tab to calculate totals across multiple days or weeks.

Weekly tab: planning a week before it happens

When you want to plan overtime ahead of time, a weekly view helps. The Weekly Overtime tab supports two input styles: you can enter hours per day directly, which is fast when you already know your expected hours, or you can enter a schedule using start/end times and breaks, which is useful when you want a realistic estimate based on your normal workday pattern.

Weekly planning is especially useful if you have a weekly overtime threshold and you want to decide whether to accept an extra shift. Small additions can tip a week over the threshold, and the overtime split can help you understand how many extra hours will be counted as overtime rather than regular time.

Timesheet tab: the most accurate way to compute overtime

A real overtime estimate requires real entries. The Timesheet tab is designed for that. You can add as many rows as you need, including multiple shifts per day. The calculator computes net hours per row, sums by date to apply daily overtime tiers, then groups dates into weeks to apply weekly overtime using your week start setting.

If you are trying to reconcile an overtime figure, this tab is the one to use. It helps you make your assumptions explicit: whether breaks are paid, how rounding is done, and which method combines daily and weekly overtime. If your results don’t match payroll, you can adjust one setting at a time until you find the policy difference.

Exporting your overtime breakdown

Export CSV generates a file that includes each row of your timesheet and your computed totals. This is useful if you want to keep a personal record, share entries with a manager, or analyze your overtime patterns in a spreadsheet. CSV is widely compatible, so it stays useful even if you change tools or workflows later.

If you only want to export part of your data, use the optional date filters before calculating and exporting. This makes it easy to export a single pay period or a specific date range without deleting other entries.

How to make results match your workplace as closely as possible

If your goal is to mirror payroll, focus on these items in order:

• Break policy: confirm which breaks are unpaid and how they are recorded.
• Overtime thresholds: confirm daily threshold, weekly threshold, and any double time tier.
• Week start day: confirm which day defines the start of the payroll week.
• Rounding: confirm whether minutes are rounded, to what interval, and whether rounding occurs before or after subtracting breaks.
• Combination method: confirm whether daily and weekly overtime stack, replace, or interact without double-counting.

Even after you match these settings, there can be edge cases. Some workplaces use different thresholds on weekends, apply special holiday rules, or apply overtime after a certain number of consecutive days worked. This calculator is aimed at the most common overtime structures and provides transparent settings so you can get as close as possible for everyday planning and verification.