Why DLS is not a run-rate calculation

What DLS does

The Duckworth–Lewis–Stern method is the model used to set a fair revised target when rain, or another interruption, shortens one or both innings of a limited-overs match. Its purpose is to answer a single question: given that a team has fewer overs to bat than it expected, what score should it be chasing so that neither side is unfairly advantaged by the stoppage?

The key idea is that a batting side has two resources at any moment, not one. It has overs remaining, and it has wickets in hand. DLS combines those into a single percentage of “resources available” using a published resource model, then scales the target by the ratio of resources the two teams actually had. That is a fundamentally different operation from dividing runs by overs.

Why DLS is not a run-rate calculation

Run rate is a single division: runs ÷ overs. Required run rate and net run rate are variations on the same idea — they compare totals against overs and nothing else. None of them knows or cares how many wickets a team has lost.

DLS does care, and that is the whole point. It uses a resource table that assigns a value to every combination of overs remaining and wickets lost. Because wickets are part of the calculation, two innings that look identical on a run-rate basis can be worth very different amounts of resource. A run-rate scaling of the target would ignore this entirely and would systematically punish or reward the side that happened to lose wickets early or late.

The two-resource illustration

Picture two teams, each on the same score after the same number of overs when rain ends the innings. Team A has lost no wickets; Team B has lost five. On a pure run-rate view they are identical — same runs, same overs, same rate. But their situations are not identical at all.

Team A, with all its wickets intact, could have accelerated hard in the overs it lost to rain; it had a great deal of unused batting resource. Team B, five down, had far less scope to attack and was much closer to being bowled out. DLS reflects this: it credits Team A with more lost resource than Team B, so the two teams are set different revised targets from the same scoreboard. Run rate cannot express any of that — it collapses the innings into one number and throws the wicket information away. That is precisely why the sport uses DLS instead of a run-rate rescale.

Why the tables are proprietary, and why we do not reimplement them

The DLS resource tables and the algorithm that applies them are proprietary. The standard match version relies on figures and a computer program that are not published in a complete, machine-usable form. As a matter of policy, this site references DLS and explains how it works, but it does not compute a DLS par score or revised target.

This is a deliberate trust and accuracy stance. We would rather tell you plainly that we cannot reproduce DLS than publish an approximation dressed up as the real method. An unofficial “DLS calculator” built from guessed or partial numbers would produce targets that disagree with the official result — and in a rain-affected match the official DLS figure is the only one that counts.

What you can compute here

Plenty of cricket maths is fully transparent, and those are the numbers we build tools for:

• Run rate — runs divided by overs faced, the simplest scoring rate.
• Required run rate — runs still needed divided by overs still available for the chasing side.
• Net run rate — the league tie-breaker, using the Net Run Rate calculator.
• Projected score — a linear extrapolation of the current rate, using the Cricket Projected Score calculator.

Every one of these is a published formula you can check by hand. DLS is the exception, and we treat it as one.

Frequently asked questions

Related tools and reading

Sources

• International Cricket Council, published description of the Duckworth–Lewis–Stern method — reference only. The resource tables and algorithm are proprietary and are not reproduced or linked here. Checked 24 Aug 2026.