Latency, jitter and packet loss
One garden, two continents
Kai plays Shard Garden in Sydney. Priya plays in London, in the same garden. When Kai plants a seed, it takes a moment to appear on Priya's screen.
Three numbers describe how a connection behaves.
Three numbers
Every online game is shaped by these:
- Latency"The time it takes for a packet of data to travel from source to a destination." Games usually measure the round trip, called ping.
- JitterHow much the delay changes from one packet to the next. MDN calls it "packet delay variation".
- Packet lossThe share of packets that never arrive at all.
Quick check
Which number says how much the delay changes from packet to packet?
- Jitter
- Latency
- Packet loss
Show the answer
Jitter
Latency is the delay itself. Jitter is how much that delay wobbles.
Distance has a floor
Sydney to London is about as far apart as two cities get. A signal needs time to cross that distance, and no code makes it travel faster.
A game cannot remove latency. It can only hide it, and the rest of this stage is how.
Steady beats fast
A steady 100 ms delay is easy to plan around. A delay that swings between 40 ms and 200 ms is harder: updates arrive in clumps, and movement stutters.
Games keep a small buffer of updates so they can play them out evenly, the way a video buffers before it plays.
Read the ping
1reply 64 ms2reply 66 ms3reply 65 ms4reply 210 ms5reply 63 ms6no reply
Remy pings the London server from Sydney. What is wrong with this connection?
- A jitter spike and one lost packet
- The latency is always too high
- Nothing: every reply arrived
Show the answer
A jitter spike and one lost packet
Most replies take about 65 ms. One jumped to 210 ms, which is jitter, and one never came back, which is loss.
Make the network worse on purpose
Chrome DevTools can add a custom network profile with its own latency in milliseconds, packet loss and packet reordering.
Remy tests Shard Garden with one that feels like Sydney to London, without leaving the office.
Quick check
A faster CPU on the server removes the latency between Sydney and London.
- True
- False
Show the answer
False
Most of the delay is the distance the signal travels. A faster CPU only speeds up the work done once the data arrives.
What a game sends
Some data must arrive, like a purchase. Some is useless a moment later, like where a player stood 50 ms ago. The way a game sends each kind matters.
Bolt says: Next: UDP, TCP, WebSockets and WebTransport.
Fact-checked 12 October 2026
- MDN: Understanding latency developer.mozilla.org
- MDN: Jitter developer.mozilla.org
- Chrome DevTools: Throttling developer.chrome.com