Duckworth Lewis Method Explained: How DLS Targets Are Actually Calculated

Rain can completely change a cricket match. A team may dominate for 30 overs, only to lose valuable playing time because of bad weather. When the match resumes, the original target may no longer be fair. This is where the Duckworth Lewis Stern method, commonly called DLS, comes into play.

DLS is used in limited-overs cricket to calculate a revised target when interruptions reduce the available playing time. It considers more than the number of overs remaining. It also accounts for wickets lost because a team with eight wickets in hand generally has greater scoring potential than a team with only three.

The method helps create a more balanced contest between teams that have had different opportunities to score. This guide explains how DLS works, how its targets are calculated, what par score means and why a shortened match can produce surprising results.

What Is the Duckworth Lewis Method in Cricket?

The Duckworth Lewis method is a mathematical system used to revise targets in rain-affected limited-overs cricket. Its updated name is the Duckworth Lewis Stern method, or DLS.

The system compares the scoring resources available to both teams. These resources are:

• Overs remaining: The number of deliveries a team still has available.
• Wickets remaining: The number of batters a team can still lose before its innings ends.

A team with more overs and more wickets in hand generally has greater scoring potential. When rain removes overs, the team loses part of its scoring opportunity. DLS estimates this loss and adjusts the target accordingly.

For example, imagine Team A scores 250 runs in a 50-over match. Rain then reduces Team B’s chase to 40 overs. Team B cannot simply be asked to score 251 in fewer overs. DLS calculates a revised target based on the resources available to both teams.

The method is used in limited-overs formats, including One Day Internationals and T20 cricket, when interruptions affect playing time and the applicable competition rules require a revised target.

Why Was the Duckworth Lewis Method Introduced?

Before DLS, rain-affected matches often used simpler methods, including Average Run Rate and the Most Productive Overs method. These approaches could produce unfair results because they did not properly account for wickets in hand and the scoring opportunities available to each team.

The problem became particularly clear during the 1992 Cricket World Cup semi-final between England and South Africa.

South Africa needed 22 runs from 13 balls when rain interrupted the match. Under the Most Productive Overs method, the revised requirement became 22 runs from just one ball. The method reduced the available deliveries from 13 to one without making a meaningful adjustment to the runs required, leaving South Africa with an almost impossible task.

The incident exposed the weakness of the Most Productive Overs method and highlighted the need for a fairer calculation.

English statisticians Frank Duckworth and Tony Lewis developed the original method during the mid-1990s to address this problem.

It was first used in an international match on 1 January 1997, when Zimbabwe defeated England in an ODI at Harare. The ICC adopted it for the 1999 Cricket World Cup. The Professional Edition followed in 2004.

Statistician Steven Stern later helped update the system, and it became known as the Duckworth Lewis Stern method in October 2014.

Frank Duckworth died on 21 June 2024, aged 84. Tony Lewis died in 2020, aged 78.

How Does the DLS Method Work?

DLS works by assigning a resource percentage to each team’s innings. The percentage represents the scoring resources available compared with a complete 50-over innings.

The calculation considers:

• The number of overs available at the start.
• The overs already used.
• The wickets lost.
• Any overs removed because of interruptions.
• The resources remaining when play resumes.

When a team loses overs, it loses part of its scoring resources. DLS compares the resources available to the first batting team with those available to the chasing team and adjusts the target.

The Two Main Resources in DLS

Resource	Why it matters
Overs remaining	More deliveries give batters more opportunities to score.
Wickets remaining	More wickets allow batters to take greater risks and attack.

These two resources work together. Having 10 wickets available with only two overs remaining does not provide the same scoring potential as having 10 wickets available with 40 overs remaining.

Similarly, a team with many overs left but only one wicket remaining has limited scoring potential.

How Does DLS Calculate Resource Losses During Rain Interruptions?

DLS does not simply subtract a fixed number of runs for every over lost.

It calculates the resource loss during an interruption by comparing the resources available when play stops with the resources available when play resumes.

For example, if rain interrupts an innings, the team may lose some of its remaining overs. The resource calculation also considers how many wickets have fallen at that stage.

If a match experiences several interruptions, the resource losses from the different interruptions are accumulated to calculate the resources available to both teams.

This is why two matches with the same number of overs lost can produce different revised targets.

How Is the DLS Target Calculated?

The calculation uses three important values:

• S: The first team’s final score.
• R1: The percentage of resources available to the first team.
• R2: The percentage of resources available to the second team.

The formula depends on whether the chasing team has fewer or more resources. The calculation also differs between the Standard Edition and the Professional Edition.

DLS Professional Edition: One Formula for Both Situations

The Professional Edition, used in international cricket, applies one proportional formula whether the chasing team has fewer or more resources than the first team.

Par Score = S × (R2 ÷ R1)

Target to win = Whole-number par score + 1

The par score is rounded down to the nearest whole number. The chasing team needs one additional run to win.

Example 1: The Chasing Team Has Fewer Resources

Suppose Team A scores 250 runs and uses 100% of its resources. After rain, Team B has only 80% of the resources available.

• Team A’s score: 250
• Team A’s resources: 100%
• Team B’s resources: 80%

Calculation:

Par Score = 250 × (80 ÷ 100)

Par Score = 200

The par score is 200, so Team B needs 201 runs to win.

Example 2: The Chasing Team Has More Resources

Sometimes rain interrupts the first innings and reduces the resources available to Team A. Team B may then receive more resources than Team A had.

Under the Professional Edition, the same proportional formula applies.

Suppose:

• Team A scores 200 runs.
• Team A uses 80% of its resources.
• Team B has 100% of the resources available.

Calculation:

Par Score = 200 × (100 ÷ 80)

Par Score = 250

The par score is 250, so Team B needs 251 runs to win.

There is no separate G50 formula for this situation in the Professional Edition. The same resource-ratio formula applies in both directions.

DLS Standard Edition: When Is G50 Used?

The Standard Edition uses a different approach when the chasing team has more resources than the first team.

It uses two branches:

Resource situation	Standard Edition calculation
R2 is less than R1	Par Score = S × (R2 ÷ R1)
R2 equals R1	Par Score = S
R2 is greater than R1	Par Score = S + [(R2 − R1) × G50 ÷ 100]

For each situation, the winning target is one run above the whole-number par score.

The upward adjustment in the Standard Edition uses G50. This is the main difference between the Standard and Professional Editions.

What Is G50?

G50 represents the average expected score in an uninterrupted 50-over innings.

For matches involving teams that play first-class cricket, the ICC methodology specifies a G50 value of 245.

The Standard Edition uses G50 when the chasing team has more resources than the first team. It calculates the additional runs required based on the difference between the two resource percentages.

The same G50 benchmark is used for different match lengths, including 40-over and T20 matches. The resource percentages are measured against a full 50-over innings.

Standard Edition formula when R2 is greater than R1:

T = S + [G50 × (R2 − R1) ÷ 100] + 1

Here:

• T = Revised target to win.
• S = First team’s score.
• R1 = First team’s resource percentage.
• R2 = Second team’s resource percentage.
• G50 = 245 for the relevant first-class and top-level cricket category.

The calculated target is rounded down to a whole number.

This formula belongs to the older D/L Standard Edition. It should not be confused with the Professional Edition DLS calculation used in international cricket.

Why Is the Professional Edition Different?

Source Image: Sportsforlife

The Standard Edition uses one fixed published table of resource percentages. The Professional Edition uses a more sophisticated model in which the resource percentages change according to the score achieved by the first team.

In other words, the Professional Edition uses a different resource table for different first-innings totals. This is why it requires specialised computer software rather than simple manual calculations.

For ordinary first-innings totals around or below the average top-level score of approximately 235 runs, the two editions generally produce similar results. As first-innings totals increase, the differences become more noticeable.

This improved resource model is why international cricket moved to the Professional Edition in 2004.

How Are DLS Par Scores Rounded?

The par score is the score the chasing team needs to reach to tie the match at a particular stage of the chase. The winning target is one run above the whole-number par score.

When a calculated par score contains a decimal, the decimal portion is ignored to establish the whole-number par score.

Example:

Suppose the calculated par score is 200.6.

• Par score for a tie: 200
• Target to win: 201

If the calculated par score is exactly 200:

• Par score for a tie: 200
• Target to win: 201

This distinction is important because the par score and the winning target are not the same.

What Is the Difference Between DLS Par Score and Target Score?

Par score and target score are two different terms that often confuse cricket fans.

Par score is the score the chasing team needs to reach at a particular point in its innings to be level under the DLS calculation.

Target score is the revised total the chasing team must reach to win the match.

For example, if the par score at an interruption is 150, the team needs 151 to win. If it has scored 155, it is five runs above par. If it has scored 145, it is five runs below par.

Term	Meaning
Par score	Benchmark score at a particular point in the chase
Revised target	Total required to win after an interruption
One run below target	A tie, if the match reaches a valid result
Above par score	Chasing team is ahead under DLS

The par score can change during the second innings as runs are scored and wickets fall. It is also recalculated when further interruptions cause overs to be lost.

Why Can the DLS Target Increase or Decrease?

The revised target does not always go down when rain reduces the number of overs.

• Target decreases: The chasing team has fewer scoring resources than the first team.
• Target increases: The first batting team loses more resources during its innings, leaving the chasing team with a relative advantage.
• Target remains unchanged: Both teams have equivalent resources available.

This is why two rain-affected matches with the same number of overs may have different DLS targets. The number of wickets lost and the timing of interruptions also matter.

A Real DLS Example: India vs Australia, 2017 ODI

A useful example is the first ODI between India and Australia in Chennai on 17 September 2017.

India scored 281 for 7 in 50 overs. Rain interrupted the match, reducing Australia’s chase to 21 overs. Australia received a revised target of 164 runs.

Australia finished on 137 for 9 in 21 overs. India won by 26 runs under the DLS method.

Match summary:

Match detail	Result
Match	India vs Australia, 1st ODI
Date	17 September 2017
Venue	MA Chidambaram Stadium, Chennai
India’s score	281/7 in 50 overs
Australia’s score	137/9 in 21 overs
Revised target	164 runs
DLS par score	163 runs
Result	India won by 26 runs

The DLS par score was 163, meaning Australia needed 163 to tie and 164 to win. Its final score of 137 was 26 runs below par, giving India a 26-run victory.

This example shows how DLS can significantly change a target when the chasing team loses a large part of its available overs.

Is DLS Used in Both ODI and T20 Cricket?

Yes. The Duckworth Lewis Stern method is used in both ODI and T20 cricket when interruptions affect the available playing time and the competition’s playing conditions require a revised target.

Format	Normal innings length	DLS application
ODI	50 overs per team	Revises targets when overs are lost
T20 International	20 overs per team	Revises targets when overs are lost
Test cricket	No fixed overs per innings	Not used

Test cricket uses different playing conditions and does not use DLS to revise targets. The method is designed for limited-overs matches.

Under standard ICC men’s international playing conditions, a minimum of 20 overs per side in ODIs and 5 overs per side in T20 Internationals is generally required to produce a result. Exceptions apply when a team is all out earlier or the chasing team reaches its target before the minimum overs are completed. Competition-specific playing conditions should always be checked.

What Happens If a Match Is Abandoned During the Second Innings?

If rain or another interruption prevents a limited-overs match from continuing, the result may be decided by comparing the chasing team’s score with the applicable DLS par score.

If the chasing team is ahead of the par score, it may be declared the winner. If it is behind par, the first team may win.

However, this depends on whether the match has met the minimum overs and other result requirements set by the relevant competition’s playing conditions.

If those requirements are not met, the match may be declared a no result.

Can DLS Be Calculated Manually?

The older D/L Standard Edition can be calculated using published resource tables and its applicable formulas.

However, international matches use the Professional Edition DLS system, which relies on a more sophisticated resource model. An ordinary percentage calculation cannot reproduce every official DLS target.

For accurate international match results, the relevant official DLS calculator and competition playing conditions should be used.

Conclusion

The Duckworth Lewis Stern method helps make rain-affected limited-overs cricket fairer by adjusting targets according to the scoring resources available to each team.

It considers both overs remaining and wickets in hand rather than relying only on run rate. The Standard Edition uses different calculations depending on whether the chasing team has fewer or more resources, while the Professional Edition uses one proportional resource formula in both situations.

Understanding resource percentages, G50, par scores and revised targets makes it easier to follow the calculations when weather changes the course of a cricket match.

Frequently Asked Questions About the Duckworth Lewis Method