TIME ENTRIES
Format: HH:MM:SS or H:M:S
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Enter time values and click Calculate
Supports HH:MM:SS — e.g. 1:30:45, 0:45:00// sum or difference hours, minutes, seconds across multiple values
Add or subtract hours, minutes, and seconds across multiple entries instantly. Free browser-based time duration calculator with sum and difference modes.
Enter time values and click Calculate
Supports HH:MM:SS — e.g. 1:30:45, 0:45:00Type durations in HH:MM:SS format. You can also write H:MM or just seconds.
Use Sum mode to add all rows, or Mixed mode to toggle individual rows as + or −.
See the total in multiple formats: HH:MM:SS, total seconds, decimal hours, and more.
The Time Duration Calculator lets you add or subtract multiple time values expressed as hours, minutes, and seconds. It handles carry-over automatically — e.g. 75 minutes becomes 1 hour 15 minutes — and outputs the result in HH:MM:SS, total seconds, total minutes, and decimal hours.
You can enter time in HH:MM:SS (e.g. 1:30:45), H:MM (e.g. 1:30), or just seconds (e.g. 90). The calculator auto-interprets and normalizes all formats.
Yes. Switch to Mixed mode and toggle any row to "−" using the sign button. The result can be negative if subtractions exceed additions.
There is no hard limit. You can add as many rows as needed, or paste a multi-line block of time values using the "Paste Multi-line" button.
Decimal hours express the total duration as a fraction of an hour. For example, 1 hour 30 minutes = 1.5 decimal hours. This is useful for billing and spreadsheet calculations.
Yes. Unlike a clock, this calculator works with durations, not times of day. Totals can exceed 24 hours without resetting to 0.
The calculator normalizes it automatically — 75 minutes becomes 1 hour and 15 minutes. Any overflow in seconds or minutes is carried over correctly.
Yes. Each row has an optional label field. Labels appear in the row breakdown section of the result, making it easy to audit which value came from where.
No. All calculations happen entirely in your browser using JavaScript. No data is uploaded or stored.
Whether you're totaling timesheet entries, summing up video segment lengths, or figuring out how long a project took across multiple work sessions, a dedicated time duration calculator saves you from manual arithmetic — and the inevitable carry-over mistakes that come with it.
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Adding regular numbers is trivial, but time is base-60 — 60 seconds per minute, 60 minutes per hour. If you add 45 minutes + 30 minutes in a regular calculator, you get 75. But 75 minutes is actually 1 hour and 15 minutes, and you need to carry that hour forward manually. Multiply that across a dozen rows and you're begging for errors.
This tool handles all of that automatically. You enter raw HH:MM:SS values, and the calculator normalizes every value, sums the total seconds, then converts back to hours, minutes, and seconds with proper carry-over.
Sum Mode treats every row as a positive duration to be added together. This is the most common use case — adding work log entries, video segments, or exercise sets.
Mixed Mode allows you to toggle individual rows between + (add) and − (subtract). This is useful when you want to subtract break time from a total shift, deduct a refund period, or compute a net duration across interleaved positive and negative intervals. The total can go negative in this mode if subtractions exceed additions.
The calculator accepts flexible input so you don't need to reformat your data:
1:30:45 (1 hour, 30 minutes, 45 seconds)1:30 (interpreted as 1 hour, 30 minutes, 0 seconds)45:30 with H = 0 (45 minutes, 30 seconds)90 (normalized to 1:30)Values like 0:75:00 (75 minutes) are normalized automatically — the calculator doesn't reject unusual inputs, it just converts them correctly.
After calculating, the result appears in four formats:
If you have a list of time values from a spreadsheet, log file, or text document, you don't need to type them one by one. Click "Paste Multi-line" and paste your entire block. The tool splits by line, creates a row for each value, and you can calculate immediately.
Video and podcast production: Add up segment durations to get a total runtime before rendering. Subtract intro/outro lengths to find net content duration.
Freelance timesheets: Sum up daily work log entries across a week. Use decimal hours output to multiply against your hourly rate and get an invoice total in seconds.
Fitness and training: Total your workout durations across sessions. Compare weekly volume by summing active time and subtracting rest periods.
Event planning: Schedule program segments for a conference or ceremony. Sum speaker slots, breaks, and transitions to make sure everything fits the total event window.
Music and audio editing: Calculate total mix length from individual track durations. Ensure your album runtime meets distribution requirements.
This tool calculates durations, not times of day. A time-of-day clock resets at 24:00. A duration calculator does not — 25 hours is a valid output if your entries sum to it. This distinction matters for long projects, multi-day recordings, or any context where cumulative elapsed time exceeds a single day.
All calculations run entirely in your browser using JavaScript. No time values, labels, or results are transmitted to any server. You can use this tool with sensitive project data or client time logs without any privacy concerns.