Worm Chart in Cricket — What It Shows and How to Read It
The worm chart is a visual overlay that compares two teams' cumulative run progressions over their innings. Learn how to read the worm, what a diverging worm means, and why broadcasters use it.
The worm chart is one of cricket's most widely used broadcast graphics. It displays two overlapping line graphs — one for each team — showing their cumulative run totals over the course of each over. The x-axis shows overs bowled, the y-axis shows total runs scored. Watching the two lines diverge, converge, and cross tells viewers at a glance who is ahead of whom at any point in the match.
How to Read the Worm
- The x-axis represents overs completed (0 to 20 in T20, 0 to 50 in ODI)
- The y-axis represents cumulative runs scored
- Team A's line (usually blue or the home team's colour) tracks their total run-by-run
- Team B's line overlays the same axes, adjusted so over 1 of Team B lines up with over 1 of Team A
- If Team B's line is ABOVE Team A's at the same over, Team B is ahead of Team A's scoring pace at that stage
- The worm updates after every ball; sharp rises indicate big overs; flat stretches indicate dot balls or wicket periods
What a Diverging vs Converging Worm Means
When the two worm lines are diverging (pulling further apart), the leading team is outscoring the chasing team over that period. When they converge (drawing closer), the chasing team is outscoring the leading team. A crossing point shows the moment the chasing team overtook the set score — in a successful chase, the worm for the chasing team crosses above the batting-first team's worm before the end of the innings.
Worm vs Required Run Rate Line
Broadcasters sometimes overlay the worm with an 'ideal line' — the path the chasing team would need to follow to reach the target scoring at a constant rate. If the chasing team's worm is above the ideal line, they are ahead of the required rate; below means they need to accelerate. This variant is particularly useful in the final 5–10 overs of a T20 chase.
Reading the Worm in a T20 Chase
Team A (batting first) scored slowly early (worm flat from overs 1–6) then accelerated (steep rise from overs 15–20), finishing at 175. Team B's worm tracks below Team A's through overs 1–12 (chasing behind the pace) then has a dramatic rise from over 16 — the worm crosses Team A's line at over 19, meaning Team B overtook the target before the final over.
Frequently asked questions
Is the worm chart used in Test cricket?
Occasionally — broadcasters may show it for comparison between innings within the same Test. But it is most useful in limited-overs cricket (ODI and T20) where both innings have a fixed length and the comparison is direct.
Why does the worm sometimes show 'par score' instead of the target?
In rain-affected matches using DLS, the par score changes dynamically based on overs remaining. The worm may show the DLS par score as a reference line so viewers can track whether the chasing team is above or below the minimum total needed to win if play is abandoned.
What does a nearly flat worm mean?
A flat section on the worm means the batting team scored very few runs in those overs — either due to dot balls, tight bowling, or wickets falling. A sharp vertical rise means a big boundary over: a six or multiple fours in one over creates a near-vertical spike.