Paste any duration format—including HH:MM:SS, 1h 15m, 90m, 5400s, or 1.25h—and the add time calculator normalizes each entry, applies rounding rules, and keeps HH:MM:SS, decimal hours, and decimal minutes synchronized.
Preview
Preview
Digital
00:00:00
Decimal Hours
0.00
Decimal Minutes
0.00
Row Breakdown
| Label | Entered | Digital | Decimal Hours | Decimal Minutes | Notes |
|---|
Add Time Calculator - Sum Hours:Minutes:Seconds Fast
Add a list of durations and compare the total in digital time, decimal hours, and decimal minutes. Label entries, review row errors, and copy or export CSV results.
Sum durations rather than clock times
The add time calculator totals the durations in the rows. For example, 1:45 + 2:30 = 4:15, or 4.25 decimal hours. The first two colon fields mean hours and minutes; a clock reading such as 09:00 is not a start timestamp on this page.
Use HH:MM, HH:MM:SS, DD:HH:MM:SS, or explicit unit text such as 1.5h, 92m, and 250ms. A bare number means seconds. For a start and end time, use the duration calculator instead.
Keep the entered rows beside the total
Add rows for separate entries and use labels or notes to identify their source. Weekly template labels organize rows; they do not infer shifts, paid breaks, or an overtime policy. Review any row errors before relying on the summary.
Copy Results produces a text summary. Export CSV downloads add-time-calculator.csv with row results and totals. Import CSV and Download CSV Template use a simple comma-separated layout. Use the template and avoid quoted fields with embedded commas; the importer is not a full spreadsheet reader.
Choose display precision before sharing
The decimal selectors affect hours and minutes. Digital time is formatted separately to milliseconds; hiding milliseconds only changes the display. Summing rounded row values can differ from rounding the unrounded total once.
Share link embeds the entered rows and settings in the URL. Recipients can read that information. Processing uses the main browser thread, so a large paste can take time; there is no fixed supported row-count or performance guarantee.