BrowserTools

Time Unit Converter

Seconds, minutes, hours, days, weeks

By Guga — BrowserTools maintainer, Tbilisi, Georgia Updated 2026-08-24
Free Private No uploads
What is Time Unit Converter?

Most time conversions are exact, and two are not. Milliseconds, seconds, minutes, hours, days and weeks are all fixed: a day is 86 400 seconds, a week 604 800. Months and years have no fixed length, so they are supplied here as the standard averages — a month of 30.436875 days and a year of 365.2425 days, the figures that make a Gregorian year average out correctly across leap years and centuries. That choice is honest about the calendar and wrong for any specific case, and the panel says so: convert one month to days and you get 30.436875, not the 31 in February. Nine units, live in both directions, with the full set listed below the converter at any moment. A decade is included and defined as ten of those average years.

Convert time units — seconds, minutes, hours, days, weeks, months and years — instantly and in all directions at once.

Private Time Unit Converter In Your Browser

Time Unit Converter is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.

Step-by-Step

How to use Time Unit Converter

1

Type the duration into Value.

2

Set From unit to the unit your figure is already in.

3

Set To unit to the unit you want, or use the swap button between the two fields.

4

Review all nine entries in the All time units grid below, keeping in mind that month and year are averages.

Key Capabilities
  • Nine units from millisecond to decade
  • Exact factors for seconds through weeks
  • Month and year supplied as documented averages rather than false precision
  • A live readout across the whole unit set under the converter
Common Use Cases
  • A developer converting a 90000 millisecond timeout into seconds to compare it against a documented limit.
  • A project manager turning a six-week sprint estimate into hours for a capacity plan.
  • A student checking whether 31556952 seconds really does equal one mean Gregorian year.
Clear Answers

Frequently Asked Questions

Why is a month not 30 days?
Because no calendar month is 30 days. The entry uses 30.436875 days, the mean length that makes 12 months average out to one Gregorian year of 365.2425 days. It is the right choice for arithmetic over long spans and the wrong one for a specific invoice period, where you should count the actual days.
Are weeks and days exact?
Yes. A day is 86400 seconds and a week is 604800, with no leap-second or calendar adjustment involved. Only the month, year and decade entries are averages; everything shorter is a definition.
What about leap seconds?
They are not counted, and neither does any ordinary calculator. A leap second is inserted occasionally to keep UTC aligned with the Earth's rotation, and the Unix timestamp that most systems use ignores them. The 86400-second day is the correct figure for that system and for the overwhelming majority of scheduling work.
Why does 1 year show as 365.2425 days rather than 365?
That is the mean across the 400-year Gregorian cycle, which needs 97 leap days to keep the average at 365.2425. A single year is 365 days unless it is a leap year, and 366 when it is, so treat the result as a long-run average rather than a calendar lookup.