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PHYSICS EXPLAINER

Is 0 ms Ping Possible? Why Tests Show Zero

Exactly zero elapsed time is not possible across a real network. A displayed 0 ms can be a rounded sub-millisecond response, limited timer resolution or an unstarted test. Check the destination, precision and completed samples before interpreting it.

Editorial model reviewed · Internet Analysis Editorial Team

The four main delay components

Propagation is travel time; serialization is time to place bits on a link; processing is work done by devices; queueing is time waiting behind other traffic.

Why tools sometimes display 0 ms

A rounded display may show 0 ms for a sub-millisecond local response. That is a measurement and formatting result, not literally zero elapsed time.

What a displayed 0 ms can mean

Illustrative readings, not results from your device
ReadingPossible explanationWhat to check
0 ms after a completed testA response was rounded or the timer could not resolve the duration.Check decimal precision and the timing method.
0.2 ms to localhostThe operating system responded locally.This does not test your router or internet path.
1 ms to your routerThe local network path is short.Compare with an external destination separately.
0 ms before startingThe interface may show a placeholder.Check completed and valid samples.

How to verify a zero reading

  1. Confirm the test finished. Missing or failed samples are unavailable, not zero.
  2. Identify the responding endpoint. Localhost, your router and an external server are different paths.
  3. Repeat to the same destination and record method, precision and successful sample count.
  4. Compare idle and busy conditions separately. A low minimum does not describe typical delay or stability.

ICMP ping, HTTP request timing and WebSocket echo timing include different work. Browser timers can also have reduced precision for privacy. A displayed zero is not evidence of instant packet delivery.

References: IETF round-trip delay metric and MDN browser timer precision.

Measure response timing to a real destination

Compare the distance-based propagation floor. If games or calls lag despite low idle timing, check timing under load.

QUESTIONS

Common questions

Can localhost ping be 0 ms?

It may be displayed as 0 ms after rounding, although computation and scheduling still take time.

What is the lowest possible internet ping?

It depends on physical path length, medium and equipment; there is no single global minimum.

Does 0 ms in a speed test prove instant internet?

No. Check whether the number is a placeholder, a rounded reading or a response from a nearby endpoint. A completed result must identify its measurement method and destination.

Continue exploring network physics

Fiber Latency Calculator: Distance to Ping RTTCalculate one-way fiber delay and round-trip latency from route distance. Compare an optional measured ping and check below-floor results without an ISP score.Distance from Ping EstimatorEstimate the maximum propagation distance compatible with a measured RTT in fiber or vacuum, with explicit limitations.New York to London Ping: Minimum RTT ExplainedWhy is 5 ms New York–London ping unrealistic? Compare calculated vacuum and fiber RTT for 5,570 km, longer-route scenarios and measurement pitfalls.

Formula and limitations

Values use transparent approximations described in the article.

Reference constants: NIST speed of light in vacuum. Fiber propagation uses a disclosed engineering approximation of 204,000 km/s; actual group velocity varies with the fiber.