Time calculator

Add or subtract durations, or multiply and divide a duration by a number.

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Time calculator processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

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Your result

Enter your values to see the result.

Reset reloads the tool with its starting values and releases open files and device controls. Saved drafts stay on this device until you delete them.

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Updated 2026-09-20

Using Time calculator

Hours may exceed 24 because these values are elapsed durations, not times on a clock. Enter h:mm:ss or h:mm. Subtraction can produce a negative duration.

Use Sum a list to total several durations at once, including negative adjustments.

A worked example

2:30:00 plus 1:45:00 is 4:15:00, or 4.25 hours. Dividing 1:00:00 by 4 gives 0:15:00.

Before you use the result

Minutes and seconds must be below 60. Clock output rounds to whole seconds; decimal outputs retain up to six places. This is duration arithmetic without dates or time zones.

Next: Time duration calculator

Next: Time from now calculator

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ToolOctopus. “Time calculator.” Updated 2026-09-20. https://tooloctopus.com/time-calculator.

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