Download time calculator
How long a file takes on your connection, bits and bytes kept apart.
Fill in the fields and the result will appear here automatically.
Converts a file size to bits, divides by your link speed and shows the time. Decimal prefixes such as MB and binary prefixes such as MiB are separate options rather than a hidden assumption, and so are bit-per-second and byte-per-second speeds. The figure is theoretical: no protocol overhead is folded in behind your back.
How it works
Formula and logic
Time in seconds = bytes·8 / bits per second. MB=10⁶ bytes and MiB=2²⁰ bytes; kbit/s, Mbit/s and Gbit/s use decimal prefixes. MB/s means bytes per second, so 1MB/s=8Mbit/s. Enter a positive file size and rate in their selected units. The model uses constant useful throughput with no extra protocol multiplier.
Example
A 1 GB file on a 100 Mbit/s link takes 8 000 000 000 ÷ 100 000 000 = 80 seconds.
Fields and units
- File size — GB
- Size unit — list option
- Connection speed — Mbit/s
- Speed unit — list option
How to use
- — Enter the file size and pick its unit.
- — Enter your connection speed and its unit.
- — Read the time the transfer would take.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- NIST: decimal and binary prefixes
- Limitation
- One-file transfer estimate at constant useful throughput. Advertised line rate, start-up delays and server limits are not measured.
FAQ
Why is my real download slower?
The figure is the theoretical minimum. Protocol overhead, server limits and shared capacity all reduce real throughput.
What is the difference between MB and MiB?
1MB=1,000,000 bytes and 1MiB=1,048,576 bytes. For the same numerical value, MiB contains 4.8576% more bytes. That percentage is constant; the absolute byte gap grows with file size.
Why divide by bits and not bytes?
Link speeds are quoted in bits per second while files are measured in bytes, so one side has to be converted. Multiplying bytes by eight does it.
Can I enter speed in megabytes per second?
Yes, MB/s is one of the speed units and is converted to bits internally.