Network Latency & Throughput Calculator

Calculate propagation delay, transmission delay, total latency, throughput efficiency, and bandwidth-delay product for network links.

Distance (km) Propagation Medium Propagation Speed (m/s) Link Bandwidth (Mbps) Packet / File Size (KB)

Number of Hops (routers) Processing Delay per Hop (ms) Queuing Delay per Hop (ms) Protocol Overhead (%) Total File Transfer Size (MB)

Propagation Delay:
t_prop = Distance (m) / Propagation Speed (m/s)

Transmission Delay:
t_trans = Packet Size (bits) / Bandwidth (bps)

Total One-Way Latency:
L = t_prop + N × (t_trans + t_proc + t_queue)
where N = number of hops

Round-Trip Time (RTT):
RTT = 2 × L

Bandwidth-Delay Product (BDP):
BDP = Bandwidth (bps) × RTT (s) — bits simultaneously "in flight" in the pipe

Effective Throughput:
T_eff = Bandwidth × (1 − Overhead%/100)

File Transfer Time:
t_file = File Size (bits) / T_eff (bps) + L

Propagation speed in fiber ≈ 2/3 × speed of light ≈ 2.0–2.1 × 10⁸ m/s (Hecht, Understanding Fiber Optics).
Propagation speed in copper ≈ 2/3 × speed of light ≈ 2.0 × 10⁸ m/s.
Free-space / wireless propagation at speed of light c = 3 × 10⁸ m/s.
Transmission delay assumes a single-link, store-and-forward model (Kurose & Ross, Computer Networking: A Top-Down Approach).
Processing and queuing delays are user-supplied estimates; real values vary by router load and queue discipline.
Protocol overhead (TCP/IP headers, ACKs, retransmissions) typically 3–10% for TCP over Ethernet.
BDP represents the optimal TCP window size needed to fully utilise the link (RFC 7323).
File transfer time assumes the file is split into packets of the specified size; the formula gives a lower-bound estimate.

In the network