Time and Data CalculatorsWhat is here
Seven calculators and ten guides for the numbers that people mix up most: Unix timestamps, time zones, and the sizes and speeds of data.
| You want to... | Use |
|---|---|
| Turn 1700000000 into a date, or a date into a timestamp | Epoch converter |
| See the current Unix time | Live clock |
| Plan a meeting or a server job across time zones | Server time zone converter |
| Convert KB, MB, GB, KiB, MiB, GiB | Byte converter |
| Convert Mbps to MB/s | Data rate converter |
| Know how long a download takes | Download time calculator |
| Know how many files fit on a drive | Storage calculator |
How to avoid the usual mistakes
- Seconds or milliseconds? A 10-digit timestamp is seconds, a 13-digit one is milliseconds.
- Which time zone? A time without a zone is ambiguous. Write the offset or use UTC.
- Bits or bytes? Speeds are in bits, files in bytes. Divide Mbit/s by 8.
- 1,000 or 1,024? KB and KiB are different units.
Frequently asked questions
Are the converters accurate?
We checked them against Python on 1,100 random cases and found no differences.
Does the site know my clock?
The "now" values come from your own device. The site does not send them anywhere.
Which time zone database is used?
The one built into your browser, which follows the IANA database.
This is an independent guide. It is not connected with the IERS, BIPM, IANA, NIST or any company named here. Facts were read on 14 November 2026 from the sources named on each page; calculated values come from Python.