TCP Bandwidth-Delay Product Calculator – BDP
Calculate TCP bandwidth-delay product and required window size for full throughput.
About This Calculator
Calculate TCP bandwidth-delay product and required window size for full throughput. Use the calculator above for instant results.
Worked Examples
- BDP = 1,000 × 0.01 / 8 = 1,250 KB in flight
- Need TCP window ≥ 1.25 MB
Answer: 1,250 KB BDP
- BDP = 1,250 KB — same BDP as above!
Answer: 1,250 KB
- BDP = 1,250 KB | Manageable
Answer: 1,250 KB
Who Uses This Calculator?
Optimize TCP window sizing.
Diagnose WAN throughput.
High-performance network design.
TCP performance study.
Common Mistakes to Avoid
❌ Small window = idle link
If BDP > TCP window, sender stops and waits for ACK. Link sits idle wasting bandwidth.
❌ Modern OS auto-tunes
Linux, Windows, macOS auto-tune TCP windows. Manual tuning rarely needed except extreme cases.
Frequently Asked Questions
BDP formula?
BDP = Bandwidth (bits/sec) × RTT (seconds). Result in bits; divide by 8 for bytes.
TCP window scaling?
RFC 1323 allows windows to 1 GB. Most OS support it. Check: sysctl net.ipv4.tcp_window_scaling.
Long fat networks (LFNs)?
High BW + high latency = large BDP. TCP needs window scaling and modern congestion algorithms (BBR).