FTP Test Calculator
Compare actual caller-identified FTP test protocols with separately supplied conversion assumptions; no prescribed strenuous test or universal correction factor.
Description
Functional threshold power (FTP) estimates from different test protocols depend on conversion assumptions.
Functional threshold power (FTP) estimates from different test protocols depend on conversion assumptions. Protocol results can differ despite the same athlete.1
The returned values include Caller protocol estimated ftp watts, Protocol estimate spread watts. The How section below explains the calculation, input rules and interpretation.
When to use FTP Test Calculator
Use FTP Test Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. No strenuous test instructions or universal correction factor is supplied.
Prepare the observed race, match or training records and the stated units. Supply independently verified rule editions, calibration tables and targets where requested.
How to use FTP Test Calculator and understand its results
- Prepare the observed race, match or training records and the stated units. Supply independently verified rule editions, calibration tables and targets where requested.
- Enter observedTestAverageWatts, callerProtocolConversionFractions, callerProtocolIds using the field table and calculation rules, then run the tool.
- Read callerProtocolEstimatedFtpWatts, protocolEstimateSpreadWatts. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| observedTestAverageWatts | Observed test average watts | list of number | Required |
| callerProtocolConversionFractions | Caller protocol conversion fractions | list of number | Required |
| callerProtocolIds | Caller protocol ids | list of string | Required |
Enter aligned nonempty nonnegative test means, positive conversion fractions≤1 and unique nonblank protocol IDs. Return estimates and max-minus-min spread.
FTP_i=testMeanWatts_i×conversionFraction_i Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| callerProtocolEstimatedFtpWatts | Caller protocol estimated ftp watts | list of number |
| protocolEstimateSpreadWatts | Protocol estimate spread watts | number |
{
"input": {
"observedTestAverageWatts": [
200,
300
],
"callerProtocolConversionFractions": [
0.95,
0.75
],
"callerProtocolIds": [
"20-minute",
"ramp"
]
},
"output": {
"callerProtocolEstimatedFtpWatts": [
190,
225
],
"protocolEstimateSpreadWatts": 35
}
}Limitations and assumptions
No strenuous test instructions or universal correction factor is supplied.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Coggan IF/TSS Normalized Power Calculator: Normalized Power weights rolling power to the fourth power. Intensity Factor and TSS then compare that result with measured FTP and represented duration. For a complementary task, use Cycling Training Zone Lookup: Cycling power-zone intervals scale from measured FTP. Overlap and absence of matching zones remain visible.
References
-
FTP Test Calculator — tool.io
Similar or alternative tools
- Coggan IF/TSS Normalized Power Calculator
Normalized Power weights rolling power to the fourth power. Intensity Factor and TSS then compare that result with measured FTP and represented duration.
- Cycling Training Zone Lookup
Cycling power-zone intervals scale from measured FTP. Overlap and absence of matching zones remain visible.