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FTP Calculator

Updated Sep 2026 Used 0 times
Enter the measured valuesUse values from one internally consistent test or planning scenario.
Select the protocol actually completed.
Use the average or best-minute power required by the selected protocol.
Used only for the W/kg cross-check.

Guest calculations stay on this device. Signed-in results sync privately.

Your result

Functional threshold power estimate

Enter your values, then calculate to see a verified result.

Inputs usedReview the information used for this result.
Full calculation and sourcesOpen Full calculation and sources to audit the formula, assumptions, fixtures, and interpretation limits.

Versioned calculationFormula v1.0.0

Method reviewed 2026-09-27TrainingPeaks - glossary of FTP, IF, NP and TSS metrics; TrainingPeaks - Training Stress Score formulaFormula v1.0.0

Method shown

The selected equation and assumptions stay visible.

Cross-checked

Supporting outputs expose unit and protocol mistakes.

Actionable

The result links to the next relevant planning task.

Result actions
1
Step 1Choose the exact protocol you performed.20-minute 280 W
2
Step 2Enter the protocol-specific power result.20-minute 280 W
3
Step 3Enter body mass for W/kg.20-minute 280 W

Interpretation

Protocol multipliers are field-test conventions and can over- or underestimate sustainable power.

Pacing, fatigue, equipment calibration, environment, and anaerobic contribution affect results.

W/kg is a ratio, not a complete cycling-performance ranking.

Use this result

Keep exploring

4 available tools
TSS CalculatorCalculate power-based intensity and training stress.Training Zones GeneratorBuild a transparent 3-, 5-, or 6-zone table.Brick Workout CalculatorPlan a bike-to-run session and transition.Lactate Threshold CalculatorInterpolate LT1 and LT2 from an entered incremental test.
Public verification recordFormula v1.0.0
Review scope
All Four Protocol Factors, W/kg, Power-zone Boundaries, And Invalid Ranges.
Review team
CalculatorGeek Expert Review Team
Verified
2026-09-27
Next source review
2027-03-27
Automated fixtures
1 cases

Review method

Recompute FTP estimate = selected test power x protocol factor. independently; verify unit normalization, protocol selection, internal consistency, and invalid boundaries.

Known limitations

  • Protocol multipliers are field-test conventions and can over- or underestimate sustainable power.
  • Pacing, fatigue, equipment calibration, environment, and anaerobic contribution affect results.
  • W/kg is a ratio, not a complete cycling-performance ranking.

Primary sources

Latest update

2026-09-27 ยท Added complete endurance-suite calculator with verified model, source ledger, premium result, and unified contextual navigation.

Published calculation checks

CaseInputsExpected result
20-minute 280 Wprotocol=20min, test_power_watts=280 w, body_mass_kg=70 kgftp_watts=266, ftp_watts_per_kg=3.8
On this page

Direct answer

FTP is estimated by multiplying the entered test power by the factor for the selected protocol.

The tool supports 20-minute, 8-minute, ramp, and 60-minute conventions, but field tests can differ from each other and from laboratory thresholds.

Use the result in the TSS Calculator or build a fresh table with the Training Zones Generator.

How to use the calculator

  1. Choose the exact protocol you performed.
  2. Enter the protocol-specific power result.
  3. Enter body mass for W/kg.
  4. Retest with the same protocol when tracking change.

Continue with Check the worked example or Interpret the result safely for the next calculation.

Inputs, outputs, and result meaning

Inputs

  • Test protocol: Select the protocol actually completed.
  • Average test power: Use the average or best-minute power required by the selected protocol.
  • Body mass: Used only for the W/kg cross-check.

Outputs

  • Estimated FTP: A displayed result from the stated method and the entered assumptions.
  • Relative FTP: A displayed result from the stated method and the entered assumptions.
  • Protocol factor: A displayed result from the stated method and the entered assumptions.
  • Threshold-zone lower reference: A displayed result from the stated method and the entered assumptions.
  • Threshold-zone upper reference: A displayed result from the stated method and the entered assumptions.

Formula and methodology

Method: FTP estimate = selected test power x protocol factor.

Factors are 0.95 for 20 minutes, 0.90 for 8 minutes, 0.75 for the best ramp minute, and 1.00 for a 60-minute test.

Worked examples

20-minute example

A 280 W average multiplied by 0.95 gives an FTP estimate of 266 W. At 70 kg, that is 3.80 W/kg.

Interpretation and limitations

  • Protocol multipliers are field-test conventions and can over- or underestimate sustainable power.
  • Pacing, fatigue, equipment calibration, environment, and anaerobic contribution affect results.
  • W/kg is a ratio, not a complete cycling-performance ranking.

Frequently asked questions

Why is my FTP lower than 20-minute power?

The 20-minute convention applies a 0.95 multiplier.

Can I compare a ramp test with a 20-minute test?

Use caution; the protocols stress different capabilities.

Does FTP equal lactate threshold?

Not necessarily. They are related training concepts measured with different protocols.

How should I compare results over time?

Repeat the same protocol, units, equipment setup, and environmental conditions, then review the supporting outputs rather than only the headline number.

Sources and transparency

CalculatorGeek independently recomputed every published fixture on 2026-09-27. Sources establish the equation, protocol, or interpretation boundary; they do not turn an estimate into a laboratory measurement or personalized advice.