What input formats are accepted for durations?

Colon format (HH:MM:SS or MM:SS), unit suffixes (s, m, h, d) like 90m or 1.5h, or plain numbers (interpreted as hours).

Does the difference handle spans across midnight?

Yes — enable dates or use the elapsed operation to compute across midnights and multi-day spans. Results are calendar-aware and exact.

How precise are conversions and decimal hours?

You can configure decimal precision (0–8). Numeric conversions and decimal-hour outputs are formatted to the requested precision.

Time Calculator

Time tools — difference, add/subtract, sum and convert

Operation

Use dates

When using dates you can compute differences across days (e.g., 2025-12-01 23:00 → 2025-12-02 02:00).

Start time

If using dates (enabled for elapsed or diff+dates), the date fields appear below.

End time

Start date

End date

Duration to add/subtract

Formats accepted: HH:MM:SS, MM:SS, number with suffix: s/m/h/d (e.g., 90m, 1.5h). If no suffix and no colon, treated as hours.

Durations list

Comma, newline or space separated durations. Accepts same formats as duration field.

Value

From → To

Decimal precision

Decimal places for decimal-hour outputs and unit conversions (0–8). Duration breakdowns show whole units for days/hours/minutes/seconds and fractional seconds to configured precision.

Results

Choose operation, enter times/dates/durations, then press Calculate.

How to use the Time Calculator

Practical explanations and accepted input formats so you get precise, unambiguous results for scheduling, timesheets, event planning and conversions.

Time difference

Compute the exact difference between two times. If you enable dates (or use the elapsed operation), the calculator handles cross-midnight spans and multi-day intervals. Result is shown as days, hours, minutes and seconds plus decimal hours.

Add / Subtract duration

Add or subtract a duration from a base time. Durations accept colon format (HH:MM:SS) or unit suffixes (e.g., 90m, 1.5h, 3600s). Negative values subtract.

Sum list of durations

Paste multiple durations and get the total duration. Useful for aggregating shift times, task lengths or video runtimes.

Unit conversions

Convert between milliseconds, seconds, minutes, hours and days. Results include a decimal-hour display (useful for payroll calculation and reporting).

Formats accepted

Colon time: HH:MM:SS or MM:SS (e.g., 1:30:00, 45:00).
Unit suffix: 90m, 1.5h, 3600s, 2d, 1500ms.
Plain number (no suffix & no colon) is interpreted as hours (e.g., 1.5 = 1.5 hours) — use explicit suffix to avoid ambiguity.