The formula
ping = 2 × distance ÷ (speed of light × 0.67) + hop delay
Where it comes from
There is a floor no provider can go below, because physics sets it. Light travels through fibre at about two thirds of its speed in a vacuum — roughly 200,000 kilometres per second — and ping measures the round trip. Between Madrid and New York, 5,760 kilometres in a straight line, that is 57 milliseconds before counting a single device along the way. In practice the cable does not run straight and every router adds its own delay, so the real ping is usually considerably higher.
How to work it out by hand
- Take the straight-line distance between the two points
- Divide by 200,000 km/s, the signal speed in fibre
- Multiply by two, because ping measures the round trip
- Add the delay of each intermediate device
What is worth knowing
It is worth separating two things people conflate: bandwidth and latency. Bandwidth is how much data fits per second and can be bought; latency is how long the first bit takes to arrive and is limited by distance. That is why paying for more megabits does not lower your ping, and why cloud gaming platforms put servers nearby rather than giving them more throughput. The answer to latency is always geographic: move the server closer. And one thing degrades ping on home connections more than distance does — bufferbloat: when the line saturates, buffers fill with queued packets and ping jumps from twenty milliseconds to several hundred even when the server is next door.