What this time unit converter does
This tool converts a value between any two units of time: milliseconds, seconds, minutes, hours, days, and weeks. Type a number, choose the unit you're starting from and the unit you want, and the result appears instantly — along with two extra reference conversions so you can see the same value at a different scale without retyping anything.
It's built for the moments where you're not sure which specific converter you need. If you already know you want minutes to hours, the dedicated minutes to hours converter gets you there in one less click — but this page handles any pairing, including the less common ones like weeks to milliseconds.
How to use it
Four fields, no calculate button — the result is always live.
- Enter your value.Type any number, including decimals. Negative values are supported too.
- Choose the unit you're converting from.Milliseconds, seconds, minutes, hours, days, or weeks.
- Choose the unit you're converting to.Pick any other unit, or use Swap to flip the two you've already chosen.
- Read and reuse the result.Copy it to a message, print it, or download it as a CSV row for your records.
How the conversion works
Every time unit here is a fixed multiple of the second, so the converter uses the second as a common reference: it converts your input into seconds first, then converts that number of seconds into whatever unit you asked for.
60 = 5,400 seconds5,400 seconds ÷
3,600 = 1.5 hours
Reference: unit lengths in seconds
These ratios are exact and never change, which is what makes the conversion reliable in both directions.
| Unit | Symbol | Length in seconds |
|---|---|---|
| Millisecond | ms | 0.001 |
| Second | s | 1 |
| Minute | min | 60 |
| Hour | hr | 3,600 |
| Day | day | 86,400 |
| Week | wk | 604,800 |
Quick examples
Common conversions, worked out and double-checked.
| Value | From | To | Result |
|---|---|---|---|
| 1 | Hour | Minutes | 60 |
| 1 | Day | Hours | 24 |
| 1 | Week | Days | 7 |
| 60 | Seconds | Minutes | 1 |
| 1,000 | Milliseconds | Seconds | 1 |
| 90 | Minutes | Hours | 1.5 |
| 2.5 | Days | Hours | 60 |
| 45 | Minutes | Seconds | 2,700 |
Need one of these as a dedicated one-click tool instead? Try hours to minutes, seconds to minutes, or the rest of the time unit converters hub.
Who uses it, and for what
- Developers converting a timeout, TTL, or duration between milliseconds and seconds when reading logs or config files.
- Students & anyone doing homework that mixes units — turning a word-problem's days and hours into a single comparable figure.
- Project planners converting a task estimate given in hours into days or weeks for a schedule.
- Payroll & timesheet users who need minutes in hours — for shift-length math, the hours calculator handles start and end times directly instead of raw durations.
Working with a raw millisecond timestamp instead of a duration? The milliseconds to time converter is built for that specific case.
Frequently asked questions
How do I convert between time units?
Multiply your value by the unit's length in seconds, then divide by the length of the unit you want in seconds. For example, to convert 90 minutes to hours: 90 × 60 = 5,400 seconds, then 5,400 ÷ 3,600 = 1.5 hours. This converter does that automatically for any pair of units.
How many seconds are in a minute, hour, and day?
A minute is 60 seconds, an hour is 3,600 seconds, a day is 86,400 seconds, and a week is 604,800 seconds. These are fixed, exact ratios and never vary.
Is an hour always exactly 3,600 seconds?
Yes, for everyday conversions. The hour, minute, and day are non-SI units accepted for use with the International System of Units, defined as fixed multiples of the second (60, 60, and 24 respectively). Occasional leap seconds added to civil clocks don't change these conversion ratios.
Can I convert milliseconds and weeks too?
Yes. The converter covers milliseconds, seconds, minutes, hours, days and weeks, and any of them can be converted to any other.
What's the difference between this and a dedicated tool like minutes to hours?
This converter lets you pick any two units from a single page, which is useful when you don't know in advance which pair you need. The dedicated pages, like minutes to hours or seconds to hours, are shortcuts to one specific conversion using the same underlying math.
Does the result update automatically?
Yes. The result recalculates the instant you change the value or either unit — there is no calculate button.
Is the converter free and private?
It is completely free with no sign-up. The calculation runs entirely in your browser — your input is never uploaded or stored on a server.
Accuracy & sources
Results come from standard time arithmetic: your value is converted into seconds using the fixed ratio for its unit, then converted from seconds into the target unit, exactly as shown in how the conversion works. There is no rounding beyond normal display precision, and every worked example on this page has been independently verified by hand.
The unit lengths used here follow the SI Brochure published by the International Bureau of Weights and Measures (BIPM), which defines the minute, hour and day as non-SI units accepted for use alongside the second. Written and reviewed by Fletcher Langley, and re-checked whenever the tool changes — last reviewed August 2026.
About the author
Operations and workforce-systems specialist with 14+ years inside shift-based industries and payroll platforms, and a BS in Industrial Engineering. Fletcher writes and reviews the calculators, converters, and guides here — from overnight-shift math to decimal payroll hours — drawing on years spent translating between 12-hour, 24-hour, and military time for real timesheets.
Written & reviewed by Fletcher Langley · Last updated: August 2026