ping

This page shows and explains how fast (in theory) your packets can travel on the Internet. Here you can select two cities and calculate the theoretical ping between them based on the distance. Scroll down for more details.

🤔 how it works

Ping is the time it takes to send a data packet from your device to another one and receive a response back.

Let’s estimate the minimum possible ping between different points on Earth. We’ll start with physics, because without it no packets are going anywhere.

In the modern world, connectivity relies on fiber-optic cables: wires filled with glass that reflects light. A very powerful laser shines from both ends, encoding and sending our stuff using light.

In a vacuum, light (in our case, the laser) travels at 299,792 km/s.

But we don’t have a vacuum, we have glass. A quick Google search says that in good conditions and good fiber, the refractive index is roughly 1.46.

Let’s calculate the speed of light in such optical fiber:

$$ \frac{299792 \,\text{km/s}}{1.46} \approx 205336 \,\text{km/s} $$

So in one second, light travels about 205 thousand kilometers.

And in one kilometer?

$$ \frac{1 \,\text{km}}{205336 \,\text{km/s}} \approx 0.0000048 \,\text{s} = 0.0048 \,\text{ms} $$

That means one kilometer is almost five microseconds.

So we can estimate ping by multiplying the distance in kilometers by 0.0048 milliseconds, and then multiplying by two (round trip).

$$ \text{ping} = \text{distance} \times 0.0048 \times 2 $$

To be fair, we add +20% on top, because in reality cables bend, snake around oceans, mountains, and country borders.

Important: these values are very far from reality, this is a best-case lower bound. In real networks, latency is increased by transponders, routers, cable bends, bored grandmas, ship captains, beavers, sharks, cows and basically anything else that can happen. Usually you can safely multiply the result by 2–3, and sometimes by 10, to get something that looks like the truth.

Still, this calculation is useful: it helps you understand the limits of what’s physically possible.

If your ping is suddenly lower than the theoretical one, congratulations: you’ve found a wormhole ✨