Why is my transfer time longer than expected?

ISP-advertised speeds are in megabits per second (Mbps), not megabytes (MBps). Because 1 byte = 8 bits, a 100 Mbps connection can transfer at most 12.5 MB per second. Real-world throughput is also reduced by protocol overhead, network congestion, and distance to the server.

What is the difference between bits and bytes?

A bit is the smallest unit of data (0 or 1). A byte is 8 bits. Network speeds are measured in bits per second (bps, Kbps, Mbps, Gbps), while file sizes are measured in bytes (KB, MB, GB). This calculator converts between them automatically.

What speeds are used in the comparison table?

Dial-up (56 Kbps), DSL (10 Mbps), 4G LTE (50 Mbps), Cable Broadband (200 Mbps), and Gigabit Fiber (1000 Mbps). These represent typical real-world speeds for each technology.

Does this account for overhead?

The calculator shows theoretical transfer time based on raw bandwidth. Real transfers are slower due to TCP/IP overhead, latency, server limits, and other factors. A practical rule of thumb is to multiply the result by 1.1 to 1.3.

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Network Speed Calculator

Calculate data transfer time based on file size and connection speed

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About this tool

Estimate how long it takes to transfer any file over any network connection. Enter the file size with its unit (bytes, KB, MB, GB, or TB) and the connection speed with its unit (Kbps, Mbps, or Gbps). The calculator instantly shows the transfer time in seconds, minutes, and hours, and explains the difference between bits and bytes. A reference table shows your file across five common connection speeds — Dial-up, DSL, 4G LTE, Cable Broadband, and Gigabit Fiber — so you can compare at a glance. Useful for planning backups, uploads, video streaming, and anything where bandwidth matters.

How to use

1 Enter the file size and select the appropriate unit (B, KB, MB, GB, or TB).
2 Enter the connection speed and select the unit (Kbps, Mbps, or Gbps).
3 Click 'Calculate' — the transfer time appears in seconds, minutes, and hours.
4 Check the comparison table to see how long the same file takes over Dial-up, DSL, 4G, Cable, and Fiber.

Frequently Asked Questions

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