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TCP Window Size Calculator

Calculate optimal TCP window sizes for network performance optimization

Bandwidth-Delay Product Calculator

Calculate the amount of data that can be in flight on your network path to determine optimal TCP window size.

ms

Bandwidth-Delay Product (BDP)

17.88 MB

= 18,750,000 bytes = 150.00 Mbits

This represents the pipe capacity - the amount of data that must be in flight to fully utilize this link.

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CRITICAL: Window Scaling Required

Default TCP window (64 KB) will severely limit throughput:

  • Maximum throughput with 64 KB window: 3.50 Mbps
  • This is only 0.05% of your available bandwidth!
  • Window size needed: â‰Ĩ 17.88 MB
  • Scale factor required: 512 (2^9)
MetricValueNotes
Bandwidth1.00 GbpsAvailable link speed
RTT150msRound-trip time
BDP17.88 MBData in flight for full utilization
Min Window Size17.88 MBAbsolute minimum
Recommended Window35.76 MB2× BDP (allows for variance)
Max Useful Window71.53 MB4× BDP (diminishing returns beyond)
Packets in Flight12,949Based on 1448 byte MSS

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Frequently Asked Questions

Common questions about the TCP Window Size Calculator

The TCP window size determines how much data can be in flight (sent but not yet acknowledged) at any time. It directly impacts network throughput, especially on high-latency or high-bandwidth links. Too small and the link is underutilized. Too large and it wastes memory.

â„šī¸ Disclaimer

This tool is provided for informational and educational purposes only. All processing happens entirely in your browser - no data is sent to or stored on our servers. While we strive for accuracy, we make no warranties about the completeness or reliability of results. Use at your own discretion.

TCP Window Size Calculator - Optimize Network Performance | Inventive HQ