Calculate a football passer’s completion percentage and next-pass scenarios, or find how many consecutive completions are needed to reach a target rate.

Required: pass completions and pass attempts from the same statistical scope.

Target mode assumes every added pass is completed and finds the minimum whole number required.

Football Completion Percentage Formula

Football pass completion percentage measures completed forward passes as a share of official pass attempts. The NCAA statistics manual states the calculation directly:

Completion Percentage = (Completions) / (Pass Attempts) × 100

The calculator requires completions and attempts from the same scope, such as one quarterback in one game, a full season, or a team total.

What Counts in the Denominator?

Use the pass-attempt total in the official box score. Do not substitute dropbacks. Standard NFL passing tables list sacks separately from attempts, and an intercepted forward pass is an attempt but not a completion. Statistical rules can treat unusual plays differently, so official box-score totals are the safest inputs.

Next-Pass Scenarios

The primary result includes two useful one-play comparisons. A completed next pass produces:

Next Complete Rate = (Completions + 1) / (Attempts + 1) × 100

An incomplete next pass leaves completions unchanged while attempts increase by one.

Consecutive Completions Needed for a Target

Target mode solves for the minimum number of added attempts that must all be completed. If n is that number and the target is written as a decimal, the inequality is:

(Completions + n) / (Attempts + n) ≥ Target
n ≥ (Target × Attempts - Completions) / (1 - Target)

The calculator rounds the threshold up to a whole pass and verifies the projected percentage. If the current rate already meets the target, the answer is zero. Once an incompletion exists, a perfect 100 percent cumulative rate cannot be restored with any finite number of later completions.

Example

A passer with 98 completions on 166 attempts has 68 incompletions. Dividing 98 by 166 and multiplying by 100 gives approximately 59.04 percent.

Interpretation and Limitations

  • Completion percentage describes outcomes, not throw difficulty. NFL Next Gen Stats uses completion probability to add context that the basic box-score rate does not contain.
  • Drops, throwaways, spikes, pressure, depth of target, and game situation are not separated by this formula.
  • Small samples can move sharply after one attempt, which is why the calculator shows both next-pass scenarios.
  • Target mode assumes every added pass is complete; it is a mathematical requirement, not a performance prediction.

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Sources

National Collegiate Athletic Association. Official NCAA Football Statisticians’ Manual, current edition.

National Football League. NFL Player Passing Statistics and Next Gen Stats Glossary, current editions.