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Sprint Predictability Calculator

Work out sprint predictability instantly with clear inputs, formula shown and shareable results.

About Sprint Predictability Calculator

Predictability is the ratio of completed to committed work, but the useful companion is velocity variability. A team averaging 28 points with a standard deviation of 5 can only commit to about 22 points if it wants to hit the commitment nine sprints in ten. Committing to the mean guarantees missing half the time, which is what erodes trust in estimates.

Formula

Predictability

say-do ratio = completed / committed; coefficient of variation = sd / mean; 90% commitment = mean - 1.28 x sd

Worked example

With the default values below, Sprint Predictability Calculator returns Say-do ratio of 82.4%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Points committedminimum 0.1
34
Points completedminimum 0
28
Sprints measuredminimum 1
6
Velocity standard deviationminimum 0 points
5 points

Results

Say-do ratio
82.4%
Velocity variability
17.9%
Commitment achievable 90% of the time
21.6 points
Predictability assessment
Moderately variable

Step by step

  1. 1Values used
  2. 2Predictability
  3. 3Say-do ratio= 82.4
  4. 4Velocity variability= 17.9
  5. 5Commitment achievable 90% of the time= 21.6 points
  6. 6Predictability assessment= Moderately variable

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Should teams aim for a 100 percent say-do ratio?

Consistently hitting 100 percent usually means padding. Something in the 85 to 95 percent range with low variability is healthier than a perfect record.

Why is variability more important than average velocity?

Because planning depends on predictability. A slower but consistent team is easier to plan around than a fast but erratic one.

Related Calculators

Sprint Predictability Calculator – Calculate Say-do ratio