Time converter
Converts durations: seconds, milliseconds, minutes, hours, and days.
90 min is 1.5 h.
- Input
Provenance
- Computed by
- units.time.convert 1.0.0, core 0.1.0
- Model
- Exact unit definitions
- Accuracy
- Exact to double precision: each conversion is one correctly rounded ratio of exact definitions
- Notes
- None
- Cites
- National Institute of Standards and Technology, Guide for the Use of the International System of Units (SI), NIST Special Publication 811
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: Exact unit definitions
Accuracy: Exact to double precision: each conversion is one correctly rounded ratio of exact definitions
When to use this: Use this for a duration: a flight time, an endurance, a logged interval, a timeout. Give it a span in one unit and get the same span in another, from milliseconds to days, which is what a fuel calculation or schedule arithmetic needs.
Limitations: This converts durations, not times of day and not dates. A day here is exactly 86,400 seconds, which is what a duration of one day means; it is not the length of a particular calendar day, and a day containing a leap second or a change of clocks is longer or shorter than this by a second or an hour. Anything that has to know what happened on a given date -- a time zone, a UTC offset, a leap second -- belongs to the time domain and not here.
Worked example: 90 minutes in hours. Source: Exact unit definitions (NIST SP 811 Appendix B). It is golden test vector v001, and every build checks the tool still gives its answer within its tolerance.
You enter
- To unit
- h
- Value
- 90 min
You get
- Converted
- 1.5 h
- Input
- 90 min
Review: Not yet independently reviewed by a metrologist.
Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Checked against: 25 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, National Institute of Standards and Technology, 2008 edition. Appendix B.8, Factors for units listed alphabetically.