Technology

Bandwidth Calculator

Calculate how long a file transfer takes for a given size and connection speed. Supports Kbps, Mbps, Gbps and MB/s with this free bandwidth calculator.

Bandwidth Calculator

File size

Size unit

Transfer speed

Speed unit

Method

How this calculator works

Convert the file size to bits (bytes × 8, with KB = 1,000 B, MB = 1e6 B, etc.) and the speed to bits per second (Mbps = 1e6 bits/s, MB/s = 8e6 bits/s). Transfer time in seconds = total bits ÷ bits per second.

Enter the file or data size and pick its unit (KB, MB, GB, or TB).
Enter the connection speed and choose its unit — Kbps, Mbps, Gbps, or MB/s.
The tool converts size to bits and speed to bits per second.
Read the estimated transfer time, broken down into days, hours, minutes, and seconds.

Examples

Worked examples

Real numbers, end-to-end results.

5 GB over 100 Mbps

= 6 min 40 sec

5 GB × 8e9 = 40,000,000,000 bits ÷ 100,000,000 bits/s = 400 s.

700 MB over 50 Mbps

= 1 min 52 sec

700 MB × 8e6 = 5.6e9 bits ÷ 5e7 bits/s = 112 s.

1 GB over 10 MB/s

= 1 min 40 sec

10 MB/s = 80,000,000 bits/s; 8e9 bits ÷ 8e7 = 100 s.

Use cases

When to use it

Estimate how long a large backup or upload will take before you start.
Compare internet plans by transfer time rather than raw Mbps numbers.
Plan data migrations between servers or cloud storage buckets.
Check whether a connection is fast enough for scheduled file syncs.

FAQ

Frequently asked questions

What is the difference between Mbps and MB/s?

Mbps means megabits per second, while MB/s means megabytes per second. Since one byte equals 8 bits, 1 MB/s equals 8 Mbps. A 100 Mbps connection therefore delivers about 12.5 MB/s at most.

How is transfer time calculated?

The file size is converted to bits, the speed is converted to bits per second, and the time equals total bits divided by bits per second. The result is then expressed in days, hours, minutes, and seconds.

Why is my real transfer slower than this estimate?

This calculator shows the theoretical best case. In practice, protocol overhead, network congestion, disk speed, and Wi-Fi interference reduce throughput, so real transfers are typically 10–20% slower.

Does bandwidth mean the same as speed?

Bandwidth is the maximum capacity of a connection, while throughput is the actual data rate achieved. This tool uses your stated bandwidth as the speed to give an ideal transfer time.

How do I convert gigabytes to bits?

Multiply gigabytes by 1,000,000,000 to get bytes, then multiply by 8 to get bits. So 1 GB equals 8,000,000,000 bits using decimal units.