THE NUMBER BEHIND THE LAG

There and
back again.

A ping is a tiny echo sent across the internet.

Your computer sends a small message, the far end sends the same data straight back, and the round trip is timed in milliseconds. Ofcom calls that time latency, or responsiveness.

ECHO, REPLY timed in milliseconds

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A home broadband router on a wooden shelf in a calm living room, its small status lights glowing softly — AI-generated image, not a photograph of a real person or place.

Ping is a round trip
Lower is snappier
Speed is not latency
Milliseconds that matter

THE SHORT ANSWER

Ping is how long
an echo takes.

Download speed is how much arrives.
Latency is how quickly anything arrives at all.

THE ECHO

Type 8 out, type 0 back

Ping uses ICMP echo messages, defined in RFC 792 in September 1981. The data received in the echo message must be returned in the echo reply.

How the echo works

THE DISTANCE

Even light takes time

Data crosses fibre as light in glass. The University of Southampton says that by sending it through air instead, light travels 50% faster.

See the numbers

WHY IT MATTERS

Calls and games feel it

Ofcom says low latency can greatly improve real-time activities such as video-calling and online gaming, and makes browsing more responsive.

Compare connections

HOW CONNECTIONS COMPARE

Which line
do you have?

Pick your type of broadband to see the typical latency Ofcom measured in its March 2023 tests. The bar shows how high the latency is: shorter is better.

Median 24-hour latency to a third-party server, from Ofcom's UK home broadband performance report (published September 2023).

TWO NUMBERS WORTH KNOWING

Fast lines, short trips,
and room to improve.

One figure from UK home broadband tests,
one from the lab working on the next fibre.

4.9–7.3 ms

Median latency on full fibre packages

Ofcom defines latency as the time it takes for a packet of data to travel to a third-party server and back. Full fibre had the lowest figures of any technology it tested in March 2023; ADSL2+ averaged around 24 ms.

FULL FIBRE · OFCOM

50% faster

Speed of light in air vs glass fibre

The University of Southampton's hollow-core fibre project sends light through air instead of ultrapure glass, and says that this way light travels 50% faster, to help cut lag in real-time applications.

HOLLOW CORE · SOUTHAMPTON

RFC 792 also notes that ICMP is an integral part of IP and must be implemented by every IP module.

FOUR THINGS THAT AFFECT IT AT HOME

Before you blame
the line.

Ofcom's consumer summary lists everyday reasons a connection can perform worse than it should. Several are inside your own home.

Move the router
Your router might be picking up interference because of its position in your home.
Check the router itself
It might need an upgrade, or it might be poorly configured.
Test at different times
More people may be using your provider's network at peak times. Ofcom treats 8pm to 10pm as peak.
Know your distance
The distance of your home from the street cabinet or exchange can affect your broadband connection.

Hands holding a game controller in front of a softly blurred screen in a dim living room — AI-generated image, not a photograph of a real person or place.

A close-up of the glowing ends of a bundle of fibre optic strands against a dark background — AI-generated image, not a photograph of a real person or place.

HOW THE ECHO WORKS

Swap the addresses,
send it home.

RFC 792, written in September 1981, defines the Internet Control Message Protocol. ICMP messages typically report errors in the processing of datagrams, and two of its message types are the echo (type 8) and the echo reply (type 0).

To answer an echo, the receiver swaps the source and destination addresses, changes the type to 0, recalculates the checksum and sends the same data back. Timing that round trip is what a ping test reports.

QUESTIONS PEOPLE ASK

Ping and latency questions

What does ping actually measure?

The round trip of an ICMP echo message and its reply. Ofcom defines latency as the time it takes for a packet of data to travel to a third-party server and back.

Is ping the same as broadband speed?

No. Ofcom's consumer summary lists latency as one of the measures beyond speed that determine user experience, alongside web-page loading time and packet loss.

What is a good ping on UK broadband?

In Ofcom's March 2023 tests, full fibre packages had median latency of 4.9 to 7.3 ms, while ADSL2+ averaged around 24 ms.

Why is my connection slower in the evening?

Ofcom says more people may be using your provider's network at peak times, which it treats as 8pm to 10pm, leading to slower speeds.

Why does latency matter?

Ofcom says low latency can greatly improve the performance of real-time activities such as video-calling and online gaming, and makes web browsing more responsive.

How can I tell if my home wifi is the problem?

Ofcom's broadband and mobile checker app can show whether your home wifi is likely to be slowing your connection. Ofcom also names a router that needs an upgrade or is poorly configured among the reasons speeds can fall short.

There and
back again.