See how long any file takes to download on 3G, 4G, 5G, ADSL, cable or fiber — and the speed you need to move it within a deadline. Free and instant.

Decimal (1 MB = 1,000 kB)
Common connections
Pick a preset to fill in a typical real-world speed.
%
TCP/IP, TLS and Wi-Fi framing usually eat 5–15% of the advertised speed.
Estimated download time
Data to transfer
Effective speed after overhead
Average throughput
Real downloads also depend on the server, network congestion and Wi-Fi quality — treat these figures as best-case estimates on a stable connection.

Time on common connections

Connection Speed Download time

About Download Time Calculator

The download time calculator tells you how long a file of any size takes to transfer over any connection. Enter the file size in kB, MB, GB or TB, pick your connection speed in Kbps, Mbps or Gbps — or grab a preset for 3G, 4G, 5G, ADSL, cable, Starlink or fiber — and the estimated transfer time updates instantly as you type.

The calculation accounts for protocol overhead: advertised speeds are raw line rates, but TCP/IP, TLS and Wi-Fi framing typically consume 5–15% of them, so the tool applies an adjustable overhead percentage before converting bits per second into a realistic duration. A comparison table shows the same file on every common connection tier, so you can see at a glance what an upgrade would buy you.

It also works in reverse: switch to the required-speed mode, set a target time, and it computes the connection speed you need to move that file within the deadline — handy for planning backups, large uploads, media deliveries or choosing an internet plan. Everything runs in your browser and is free to use.

How to use Download Time Calculator

  1. Enter the file size and pick its unit — switch between decimal (1 MB = 1,000 kB) and binary (1 MiB = 1,024 KiB) units if needed.
  2. Set your connection speed manually, or click a preset such as 4G LTE, 5G, cable or gigabit fiber.
  3. Adjust the protocol overhead percentage if you want a more or less conservative estimate.
  4. Read the estimated download time and compare it across common connection tiers in the table.
  5. To plan for a deadline, switch to the required-speed mode, enter the target time, and read the speed you need.

Frequently asked questions

File size is converted to bits (1 byte = 8 bits), the connection speed is reduced by the overhead percentage, and the time is simply bits divided by effective bits per second. A 1 GB file on a 100 Mbps line with 10% overhead takes about 1 GB × 8 ÷ 90 Mbps ≈ 89 seconds.

Advertised speeds are raw line rates. TCP/IP and TLS headers, Wi-Fi framing, server throughput limits and network congestion all reduce the useful payload rate — that is why the calculator applies a configurable overhead percentage, and why real-world results can still vary.

MB (megabyte) uses decimal units of 1,000, while MiB (mebibyte) uses binary units of 1,024 — the calculator supports both. Mbps measures megabits per second and MBps megabytes per second; divide Mbps by 8 to get MBps.

Yes. The math is identical — just enter your upload speed instead of your download speed. Note that many home connections are asymmetric, with upload speeds far lower than download speeds.

Yes. Everything is computed instantly in your browser — no sign-up, no charge, and nothing about your files or connection is uploaded anywhere.


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