Decoding DLS: The Math Behind Cricket’s Rain Rule

Rain can change the course of a cricket match in minutes. To keep things fair when overs are lost, cricket relies on a calculation called the Duckworth-Lewis-Stern (DLS) method — a system designed to reset targets scientifically rather than by guesswork.

How the DLS method works
Introduced in 1997, DLS comes into play when limited-overs matches are interrupted — usually by rain — but enough time remains for a result. Instead of simply using the current run rate, it considers a mix of factors: runs scored, overs bowled, overs left, and wickets in hand.

Each team is assigned a “resource percentage,” representing its potential to score runs in the remaining time. Using pre-calculated tables, DLS adjusts the target for the chasing team based on how much of its scoring resource remains. This ensures that both sides face an equally fair challenge, even when the match is shortened.

A practical example
Imagine a 50-over game where Team A scores 180 after a rain delay reduces the game to 40 overs. If Team A had been 79-3 after 20 overs before the break, the DLS method calculates that Team B’s revised target should be around 185 — slightly higher to balance out conditions and lost opportunities.

Who developed DLS?
The system was created by English statisticians Frank Duckworth and Tony Lewis after the controversial rain-affected matches of the 1992 World Cup. Their goal was to remove confusion and bring fairness through numbers. Later, Australian statistician Steven Stern refined the formula, leading to its renaming as Duckworth-Lewis-Stern in 2014.

Today, DLS is the standard for all international and domestic limited-overs cricket, ensuring that rain affects the mood — not the fairness — of the match.

Please follow and like us: