Latency vs distance

Type km, a medium, and overhead. 1000 km in fibre gives 5,00 ms. Vacuum gives 3,33 ms. 8000 km and 2 ms give 42,00 ms. Distance over c, not traceroute.

Distance over the speed of light in the medium, not traceroute and not ping. File time sits on file download time.

Input data

Additional options (optional)

Results

Enter data and click Calculate.

How it works

Latency vs distance in this calculator divides kilometres by speed. 1000 km and fibre give 5,00 ms one-way. 1000 km and vacuum give 3,33 ms. 8000 km, fibre and overhead 2 give 42,00 ms. Fibre is 200000 km/s, vacuum 300000. This is not traceroute.

Field lat-distance is kilometres in metric. Select lat-medium is fibre or vacuum. Field lat-overhead-ms adds fixed ms. 1000 / 200000 × 1000 = 5. 1000 / 300000 × 1000 ≈ 3.33. 8000 / 200000 × 1000 + 2 = 42. RTT on the page is twice one-way.

5,00 ms is not a hop from mtr. 3,33 ms does not come from ping. 42,00 ms is not p99 from APM. You type the km. The calculator does not know the cable path.

File download time next door divides a file by Mbps. MTU counts fragments. Here 1000 km stays 5,00 ms, the c limit alone.

Type 1000, leave fibre and overhead 0, then Calculate. One-way is 5,00 ms. A comma in 1000,5 works. Zero km leaves the overhead alone. This is not a link measurement.

1000 km and fibre give 5,00 ms. 1000 km and vacuum give 3,33 ms. 8000 km and 2 ms give 42,00 ms. Another medium at 1000 changes 5,00 ms.

Formula

one-way ms = km / speed × 1000 + overhead. Fibre 200000 km/s, vacuum 300000. RTT = 2 × one-way. Not traceroute.

How to use

  1. Type 1000 km, leave fibre and overhead 0.
  2. Click Calculate. One-way is 5,00 ms.
  3. Vacuum at 1000 km gives 3,33 ms. 8000 km and overhead 2 give 42,00 ms.
  4. Distance over c, not traceroute.
  5. File time sits on file download time.

1000 km in fibre = 5,00 ms

Distance over c. 1000 km and fibre give 5,00 ms. This is not traceroute.

Latency
One-way from km. 1000 km in vacuum leaves 3,33 ms. Not ping.
distance
Field lat-distance. 8000 km plus 2 ms gives 42,00 ms.
fibre
200000 km/s. 1000 km gives 5,00 ms. Vacuum is faster.

Examples

Example 1

  • 1000 km
  • fibre
  • overhead 0

5,00 ms

What one-way at 1000 km in fibre? 5,00 ms. Distance over c, not traceroute.

Example 2

  • 1000 km
  • vacuum
  • overhead 0

3,33 ms

What about 1000 km in vacuum? 3,33 ms.

Example 3

  • 8000 km
  • fibre
  • overhead 2 ms

42,00 ms

What about 8000 km, fibre and 2 ms overhead? 42,00 ms.

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Common questions

What about 1000 km in fibre?

5,00 ms one-way. 1000 / 200000 × 1000. Not traceroute.

What about 1000 km in vacuum?

3,33 ms. 1000 / 300000 × 1000.

What about 8000 km and 2 ms overhead?

42,00 ms. 40 from the path plus 2.

Is this traceroute or ping?

No. The calculator does not know hops. Distance over c plus overhead.

Is 5,00 ms RTT?

No. The the result is one-way. RTT on the calculator is 2 × 5,00 ms.

What does overhead do?

It adds fixed ms. 2 at 8000 km gives 42,00 ms instead of 40.

Does a comma in 1000,5 work?

Yes. 1000,5 km in fibre gives a different one-way than 1000.

Where do I time a file?

On file download time. Here the c limit stays.

Does zero km count?

Yes as overhead alone. A blank field is a number error.

Knowledge sources

The calculator counts bits, bytes or throughput from your numbers. Below are SI and bit definitions (NIST).

Page updated in 2026.