Latency and Round-Trip Time Calculator
Estimates the delay physics puts on a network path.
Round-trip time
— ms
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
One-way latency — ms
Of which distance, one way — ms
Of which routers, one way — ms
Of which serialisation, one way — ms
Reading this —
The formula
one way = distance ÷ signal speed + hops × delay + links × packet size ÷ link speed round trip = 2 × one way
Light in fibre travels at about 204,000 km/s, roughly 5 ms per 1,000 km.
What to watch out for
Bandwidth cannot buy back this delay. A faster link only shortens the serialisation part.
Frequently Asked Questions
What is the minimum round trip over 5,500 km of fibre?
About 54 ms, before any routers or queues.
Why is geostationary satellite slow?
The satellite is about 35,786 km up, so each way goes up and down. One round trip takes at least 477 ms.