📡 Bandwidth Delay Product Calculator
Enter your link’s bandwidth and round-trip time (RTT) to calculate the bandwidth-delay product, a key figure for sizing TCP buffers.
Mbps
ms
What this calculator does
The bandwidth-delay product (BDP) tells you how much data can be ‘in flight’ on a network link at any given moment — the maximum amount sent before the first acknowledgment can return.
How the calculation works
BDP is calculated as Bandwidth (in bits per second) multiplied by Round-Trip Time (in seconds). The result in bits is then converted into bytes and kilobytes for easier reference when sizing TCP send/receive buffers or window sizes.
Network engineers use this figure to avoid a bottleneck known as the ‘long fat network’ problem, where a small TCP window size prevents a fast, high-latency link from ever reaching its full throughput.
Last reviewed August 2026