How many microseconds are in a millisecond?
There are exactly 1000 microseconds in a millisecond.
milliseconds to microse…
Exact. Both units are fixed lengths, so this conversion has one right answer.
1 millisecond is 1,000 microseconds, exactly.
| Unit | Value | Basis |
|---|---|---|
| nanoseconds | 1,000,000 | exact |
| microseconds | 1,000 | exact |
| milliseconds | 1 | exact |
| seconds | 0.001 | exact |
| minutes | 0.00001667 | exact |
| hours | 2.7778 × 10⁻⁷ | exact |
| days | 1.1574 × 10⁻⁸ | exact |
| weeks | 1.6534 × 10⁻⁹ | exact |
| months | 3.8026 × 10⁻¹⁰ | average |
| years | 3.1689 × 10⁻¹¹ | average |
| decades | 3.1689 × 10⁻¹² | average |
| centuries | 3.1689 × 10⁻¹³ | average |
The rows marked "average" use a Gregorian mean year of 365.2425 days and a mean month of 30.436875 days, which is that year divided by twelve. A real month is 28, 29, 30 or 31 days, so if you need a real one, use the days between dates calculator with real dates.
The answer in full
| Exact | 1000 |
|---|---|
| Same figure, as an average | 1000 |
| In 2026 | a common year |
Why this one is exact
Both units here are fixed lengths, defined in terms of each other and never varying. Sixty seconds make a minute, sixty minutes make an hour, twenty-four hours make a day, seven days make a week. Nothing in that chain depends on which month or which year you are in, so the conversion has one right answer.
The one caveat is the day, which is 23 or 25 hours on the two days a year the clocks change, and very occasionally 86,401 seconds when a leap second is inserted. For converting a duration, 24 hours is the right assumption. For working out when something actually happens, use the hours calculator, which uses the real timezone rules for the date.
Frequently asked questions
How many microseconds are in a millisecond?
There are exactly 1000 microseconds in a millisecond.
Is that figure exact?
Yes. Both microseconds and milliseconds are fixed lengths, so the conversion has one right answer and no assumption is involved.