1. The Problem DLS Solves
Imagine the team batting second needs 180 to win and is cruising at 120 for 2 after 25 overs, with 25 overs still to bat. Then the rain comes and the match is cut short. They have not reached 180 — but they were well placed to. Do they lose? Win? What target is fair for the overs they actually got?
A naive fix would be to compare run rates. But run rate hides something crucial: wickets. A side at 120 for 2 is in a completely different position from one at 120 for 8, even though the runs and overs are identical. Any fair method has to account for both. That is exactly what DLS does.
2. The One Big Idea: Resources
DLS treats every innings as a store of "resources," made up of two things: overs remaining and wickets in hand. A team starting a 50-over innings has 100% of its resources — all its overs, all ten wickets. Every ball bowled and every wicket lost spends some of that store. Because the method knows how much resource any combination of overs and wickets represents, it can compare two innings fairly even when they were different lengths, and set a target in proportion to the resources each side actually had.
This is the whole trick. Once you can express an innings as a single percentage — "this team had 75% of a full innings to work with" — the rest is arithmetic. A team that had fewer resources should chase a smaller target; a team that somehow had more should chase a larger one.
3. The Formula
With resources defined, the target follows directly:
If Team 2 has fewer resources than Team 1 had, the target scales down in proportion. If a quirk of the interruptions left Team 2 with more resources than Team 1, the method adds a bonus based on an average total rather than simply scaling up, because scaling up would over-reward them. That "average total" is a fixed reference figure the method calls G50 for 50-over cricket.
4. A Worked Example
Take the simplest case first. Team 1 makes 250 in a full 50 overs, so they used 100% of their resources. Rain then means Team 2 only gets 30 overs, which the resource table values at about 75.1% of a full innings.
Team 2 made fewer resources available, so their target dropped from 251 to 188. That is DLS doing its job: it did not just chop the target by the ratio of overs (which would have given 250 × 30/50 = 150), because a team batting only 30 overs can throw the bat from the start and score faster — the resource table captures that, which is why 188 is higher than a naive overs-based 150.
You can try any scenario yourself on our free DLS calculator, which uses this exact method.
5. Standard vs Professional Edition
There are two versions of DLS, and knowing which is which matters. The Standard Edition uses one fixed resource table for every match and is the version published for club and amateur cricket — simple enough to apply with a printed table and a calculator. The Professional Edition, used in all international and major domestic matches, adjusts its resource figures according to the first-innings score, because high-scoring games behave differently from low-scoring ones. The Professional Edition runs on licensed software and its exact numbers are not published.
This is why any free online calculator, including ours, gives a Standard Edition estimate. It will be very close to an official target and is perfect for club cricket, but for a televised international the broadcast figure comes from the Professional Edition and can differ slightly. Being honest about that distinction is the difference between a tool you can trust and one that quietly misleads.
6. Where DLS Came From
The method exists because of a farce. In the 1992 World Cup semi-final, an older system called Most Productive Overs left South Africa needing an impossible 21 runs off one ball after a rain break — a result so absurd it made global news. Two English statisticians, Frank Duckworth and Tony Lewis, devised a fairer alternative built on the resources idea, and it was adopted internationally later that decade.
When the pair retired, Australian academic Steven Stern took over as custodian and refined the model for modern, higher-scoring cricket. In 2014 his contribution was recognised by adding his initial, and the method became Duckworth-Lewis-Stern — DLS.
For a fully worked, step-by-step interruption, see how DLS is calculated. If you want to know what your team needs to be on right now during a chase, our guide to the DLS par score covers that.