Calculate required run rate from the balls remaining

Set the inputs before calculating

This is an original example with a fixed target of 151 and a scheduled allowance of 20 six-ball overs. The chasing side has 131 after 17.2 overs. Assume the target and innings length have stayed the same, play can continue, and the innings has not ended.

The target is the score the chasing side must reach to win in this example. Subtract 131 from 151 to get 20 runs still required. The scheduled 120 valid balls minus 104 already used leaves 16. Ordinary decimal subtraction of 17.2 from 20 would give 2.8 and mix the two units. Use the balls count as the denominator.

Work in balls and convert the final rate

1. Convert 17.2 to 17×6+2=104 valid balls used.
2. Convert the 20-over allowance to 20×6=120 valid balls.
3. Subtract 104 from 120 to get 16 valid balls remaining.
4. Subtract 131 from 151 to get 20 runs needed.
5. Calculate 20÷16=1.25 runs per ball and multiply by six to obtain 7.5 runs per over.

Update the inputs after each event

Suppose the next valid ball brings four runs. The example now needs 16 from 15 balls, giving 16×6÷15=6.4 per over. If the next valid ball instead brings no runs, it needs 20 from 15, giving 8.0. Those are separate hypothetical next events.

An ordinary one-run wide changes only the score in this example. The runs needed fall by one while the legal-ball allowance remains unchanged. From the starting example, 19 from 16 is 7.125 per over, often rounded for display. MCC’s valid-ball distinction explains why the run total can rise while the legal-ball count stays fixed.

Use the right rate for the remaining task

The current rate describes what has already been scored over the balls already faced. The required rate uses the target and balls still available. A side can have a strong current rate while still facing a demanding target, or a modest current rate while needing little to finish.

If an interruption changes the official target or permitted balls, start from the newly announced figures. Check the live official scorecard, preserve the units, and label rounded figures as rounded. For example, a new target and revised balls allowance change two inputs at once, even if the team’s score remains the same at the interruption.