TCP Throughput Calculator

Estimate the upper bound on a single TCP flow's throughput from the round-trip time and packet-loss rate using the Mathis formula: T ≤ (MSS × C) / (RTT × √p). It's the classic back-of-envelope model that shows why even small packet loss caps long-distance throughput — e.g. a 100 ms path with 0.1% loss tops out around 4.5 Mbps regardless of link capacity. Also computes the bandwidth-delay product (the window needed to fill the pipe) and the inverse: the maximum packet loss sustainable for a target throughput. The sensitivity table shows throughput collapsing as loss rises. Pure arithmetic, in your browser.