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TCP Window Size Calculator

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: 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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ℹ️ 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.