Time Card Calculator

Total 31 dated shifts with breaks, overnight ends and overlap checks; export CSV or JSON.

Add up to 31 dated shifts, mark overnight ends explicitly and subtract only the break minutes you choose. Review whole-minute totals, then download CSV or JSON. Overlapping shifts are rejected to prevent double counting.

Shift dates and times are processed locally without uploading or saving them. The optional files include your entered shifts. Editing or removing a shift clears the previous output.

This tool runs entirely in your browser. Your data is never uploaded, never stored, and never leaves your device.

Combine up to 31 dated shifts with explicit overnight ends, whole-minute break deductions and overlap checks; export CSV or JSON.

How to use it

1Enter each start date, start/end time and any next-day end.
2Enter only the break minutes you want deducted; remove unused shifts.
3Review gross, deducted and net minutes with the per-shift breakdown.
4Download CSV or JSON; changes clear stale totals.

Example

Input: 09:00–17:30 minus 30 minutes; separate 22:00–06:00 next-day shift minus 45 minutes.
Output: 990 gross − 75 break = 915 net minutes; 15:15; 15.25 hours.

Scheduled wall-clock totals, without payroll, paid-break, overtime or automatic DST rules.

What happens to your data

Shift records stay in browser memory. No name, employee identifier or pay rate is required. Optional downloads contain the entered records.

Last updated October 2026

A useful time card makes its deductions and overnight assumptions visible. This calculator combines up to thirty-one dated shifts, subtracts only the whole break minutes you enter and shows both gross and net totals. Each shift has an explicit next-day option, so an end of 06:00 is not silently interpreted as either morning or an overnight finish.

Overlapping intervals are rejected before they can inflate the total. Download a row-by-row CSV for a spreadsheet or a JSON record for further processing. It is a scheduled wall-clock quantity tool: it does not determine paid-break policy, wages, overtime, rounding rules or legal compliance.

How it works

For each shift, gross minutes = end clock minutes − start clock minutes, plus 1,440 when its end is marked next day. A shift must have positive duration. Enter break deductions as nonnegative whole minutes, no larger than that shift's gross duration. Net minutes = gross minutes − the entered deduction. A shift whose entire duration is deducted has zero net minutes and stays visible rather than disappearing.

A shift date is the date its start belongs to. Overnight ends belong to the following date. The tool converts these into a shared calendar-minute basis to detect overlap, including one shift extending into another date. Adjacent intervals can meet at the same endpoint; an interval starting before the previous one ends is rejected. Input order is preserved in the report even though a separate sorted view is used for that check.

This simple overlap check treats each complete shift as occupied time. It does not know where a duration-only break falls inside that shift, so a second shift placed inside an entered break is still considered overlapping. Split or correct your records rather than assuming two simultaneous intervals should be billed twice. Remove unused rows; each remaining row requires valid dates and times.

All shifts use a shared wall-clock basis without automatic timezones or daylight-saving adjustment. A scheduled 22:00 to 06:00 is counted as eight hours before break deductions, even if a real local clock changed during the night. For elapsed instants with known offsets, use the separate Time Duration Calculator. Do not combine records from different local clock bases without first converting them appropriately.

The calculator sums integer minutes before formatting. Hours:minutes is a time quantity, while decimal hours divide minutes by sixty and round to six decimal places. For example, 7:15 is 7.25 hours, not 7.15. The CSV includes both exact minute fields and labelled rounded decimal-hour fields, plus a total row. JSON includes the same breakdown and its calculation basis. No name, employee identifier or pay rate is required.

Break deduction is your input, not a recommendation that a break is unpaid. There are no hidden meal-period rules, shift rounding, overtime thresholds, rates or deductions. The output can help review a timesheet, but it is not a payroll calculation or a determination of work entitlements. Up to thirty-one shifts are supported; these need not be a five-day week, but real project records should be reviewed for the intended period.

Worked example: A day shift and a separate overnight shift

Input: 19 October: 09:00–17:30, 30-minute deduction. 20 October: 22:00–06:00 next day, 45-minute deduction.
Result: 990 gross minutes − 75 break minutes = 915 net minutes; 15:15 hours:minutes; 15.25 decimal hours.

Break deductions demonstrate arithmetic, not paid-break or overtime policy. The basis is scheduled wall-clock minutes.

Common use cases

Review daytime and overnight shifts in one private local calculation.
Separate gross attendance minutes from explicitly entered break deductions.
Detect duplicate or overlapping shift records before exporting totals.
Download exact integer-minute fields for a spreadsheet instead of summing rounded display values.

Frequently asked questions

How are work hours calculated with breaks?＋

Subtract the start time from the end, add one day only when selected, then subtract your break deduction. A 09:00–17:30 shift with a 30-minute deduction gives 480 net minutes or 8:00. The tool does not decide whether a particular break should be deducted.

Can I enter an overnight shift?＋

Yes. Use the start date and select that shift's End is next day option. A 22:00–06:00 interval has 480 gross wall-clock minutes. Enter its break minutes separately. The following calendar date is used when checking overlap with other shifts.

Why are two shifts rejected as overlapping?＋

Their dated gross intervals share time. The tool rejects this to prevent double counting. Adjacent endpoints are allowed. A duration-only break has no known location inside a shift, so it does not create an automatically reusable gap.

Does this calculate pay or overtime?＋

No. It totals wall-clock time and your entered break deductions. Wages, paid breaks, overtime, work-time rounding and legal rules are not inferred. Check the applicable arrangement separately before using totals for payroll.

Why are decimal hours different from hours:minutes?＋

A minute is one sixtieth of an hour. For example, 15 hours 15 minutes is 15.25 decimal hours. Decimal fields are rounded to six places; the whole-minute fields remain the exact totals.

Are my shift records stored?＋

The tool processes records locally without uploading or saving them. Your optional CSV or JSON file contains the entered records. Editing, removing or adding a shift removes the previous result and downloads.