Lap Time Predictor
Project your optimal lap time based on sector-by-sector improvements and current tire condition. Useful for analyzing practice sessions and setting realistic race targets.
About this calculator
This calculator projects a target lap time by taking your current lap time, subtracting the sum of the time gains you expect from each of three sectors, and then applying a tire-condition penalty factor: predicted time = (current time − total sector improvement) × tire penalty factor. The tire penalty scales linearly with a 1–10 condition rating you provide, where a rating of 10 (fresh) applies no penalty and a rating of 1 (worn out) adds a full 3% to the lap time — the model assumes this degradation is proportional to how far below fresh the tires are, which is a simplification of the more complex, often nonlinear wear curves real tires actually follow. The "tire adjustment" output isolates just that penalty in seconds, letting you see how much of your projected time is lost purely to grip loss versus gained from technique.
A consistency target is also generated as a rough benchmark: 0.3% of your predicted lap time, intended as a realistic window for lap-to-lap variation once you're driving at that pace — useful for judging whether you're actually extracting the improvement or just having one good lap. This tool is only as good as the sector-improvement estimates you feed it, so it works best paired with real data-logger splits or a coach's specific, measurable feedback rather than optimistic guesses, and it doesn't account for changing track conditions, fuel load, or traffic across a session.
Inputs
Results
Predicted Lap Time
89.89 sec
How to Use This Calculator
- Enter Current Lap Time, Sector 1 Improvement, and Sector 2 Improvement.
- Set Sector 3 Improvement and Tire Condition.
- Review the Predicted Lap Time (sec) result.
- Use Total Improvement (sec) and Tire Adjustment (sec) to inform your decision.
How the result changes with Current Lap Time
| Current Lap Time | Predicted Lap Time |
|---|---|
| 45 | 44.62 sec |
| 68 | 67.75 sec |
| 135 | 135.16 sec |
| 225 | 225.7 sec |
What each input means
- Current Lap Time
- Your current best or average lap time in seconds. Use your most recent representative lap.
- Sector 1 Improvement
- Expected time gain in sector 1 based on data analysis or coaching feedback.
- Sector 2 Improvement
- Expected time gain in sector 2. Compare your splits against the theoretical best.
- Sector 3 Improvement
- Expected time gain in sector 3. Focus on corner exit speed onto straights.
- Tire Condition
- Rate tire condition from 1 (worn out) to 10 (fresh). Worn tires add up to 3% to lap time.
What each result means
- Predicted Lap Time
- Your projected lap time after all improvements and tire adjustment.
- Total Improvement
- Combined time gained across all three sectors.
- Tire Adjustment
- Time added due to tire wear. Fresh tires (10) add zero penalty.
- Consistency Target
- Aim for lap-to-lap variation within this window (0.3% of predicted time).
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersCurrent Lap Time = 90, Sector 1 Improvement = 0.2, Sector 2 Improvement = 0.3, Sector 3 Improvement = 0.15 = 5 input(s) provided
- Calculate Predicted Lap TimePredicted Lap Time89.886 = 89.886
- Calculate Total ImprovementTotal Improvement0.65 = 0.65
- Calculate Tire AdjustmentTire Adjustment0.54 = 0.54
Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the tire condition penalty apply to the whole predicted time, not just the current lap time?
The formula computes (current time − total sector improvement) first, then multiplies that already-improved time by the tire penalty factor, so the penalty scales with your faster projected pace rather than your current one. Practically this means the tire adjustment output — the seconds added by wear — is measured against the time you're trying to achieve, which is a more realistic tax on a quicker lap than applying it to your slower baseline.
How much does tire condition actually change my predicted lap time?
The penalty scales linearly from 0% at a condition rating of 10 (fresh) up to 3% at a rating of 1 (fully worn), so a rating of 5 adds about 1.5%. On a 90-second lap that's roughly 2.7 seconds at the worst rating, which the calculator reports separately as the Tire Adjustment output.
What does the Consistency Target number mean?
It's set at 0.3% of your predicted lap time as a rough benchmark for how tightly your laps should cluster once you're actually running at that pace — for a 90-second predicted lap that's about a quarter of a second. It's not derived from your actual variability, just a generic yardstick for judging whether a quick lap reflects a real pace improvement or a one-off.
Why might my actual lap time differ from the prediction?
The model only accounts for the sector improvements and tire condition you enter — it has no way to factor in changing track temperature or grip, fuel load burning off over a run, or traffic that costs you time in a sector. It's also entirely dependent on the accuracy of your sector-improvement estimates, so predictions based on data-logger splits will track reality far better than optimistic guesses.
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