Byte size converter — KB, MiB, GB and transfer time
Convert between data-size units and estimate how long a file takes to transfer at a given speed. It calculates in your browser (0 uploads, works offline).
How to use it
- Enter your value in the field above.
- The result appears instantly.
- Copy or Download it.
FAQ
How do I convert MB to GB (and estimate download time) for free?
Enter a size and unit and the exact bytes plus a human-readable size appear instantly in your browser, with no upload. Add a connection speed in Mbps and it estimates the transfer time.
What's the difference between MB and MiB?
MB is a power of 1000 (a million bytes); MiB is a power of 1024 (1,048,576 bytes). Storage is usually sold in the decimal units, while operating systems often report the binary ones — which is why a "1 TB" drive shows as about 931 GiB.
Is my data uploaded?
No. The calculation runs locally and nothing is stored; it works offline.
How is transfer time estimated?
Size in bits divided by speed in bits per second — a theoretical best case that ignores overhead and congestion.
Limits
Transfer time is a theoretical maximum; real speeds are lower. Covers bytes up to terabytes.
Related
The unit converter handles physical units; the number base converter handles number systems.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.