Bandwidth Calculator

Calculate file transfer time, required bandwidth, or data amount. Select which value to compute, enter the other two, and get instant results.

Results update as you type.

Common Bandwidth Reference

How It Works

The bandwidth calculator uses the fundamental relationship between data size, transfer speed, and time:

• Transfer Time = File Size / Bandwidth
• File Size = Bandwidth × Transfer Time
• Bandwidth = File Size / Transfer Time

All values are internally converted to bits and bits per second for consistent calculation. Network speeds are typically measured in bits per second (Mbps, Gbps), while file sizes are measured in bytes (MB, GB). Since 1 byte = 8 bits, a 100 Mbps connection transfers about 12.5 MB per second.

Bits vs Bytes

A common source of confusion is the difference between bits and bytes. Internet service providers advertise speeds in bits per second (e.g., 100 Mbps), while files and operating systems display sizes in bytes (e.g., 500 MB). To convert between them, divide or multiply by 8.

Real-World Throughput

Actual transfer speeds are often lower than the advertised bandwidth due to protocol overhead (TCP/IP headers, packet retransmission), network congestion, server-side limits, and hardware bottlenecks. A rough rule of thumb is to expect 60-80% of the theoretical maximum in practice.