20-Minute Functional Threshold Power (FTP) Calculator
The formula
What is Functional Threshold Power (FTP)?
Coined by Dr. Andy Coggan, Functional Threshold Power (FTP) is defined as the highest power output a cyclist can maintain in a quasi-steady state for approximately 60 minutes without fatiguing. It serves as the baseline benchmark for all structured power-based training zones, intervals, and Normalized Power (NP) metrics.
Frequently asked questions
Why do we deduct 5% from the 20-minute test?
Source & methodology
Allen H, Coggan A. "Training and Racing with a Power Meter." VeloPress 2010.
20-Minute Functional Threshold Power (FTP) explained: formula, worked example and honest limits
This page was written for one job: turning your own inputs into a defensible figure, with the working shown. Searchers land on a 20-Minute Functional Threshold Power (FTP) page for three reasons — to plan, to compare options, and to check that somebody else’s arithmetic is honest. This tool serves all three, and everything after the calculator explains the model instead of hiding it.
Training math in Fitness & Sports converts effort into load, and load into adaptation. 20-Minute Functional Threshold Power (FTP) does the conversion: FTP = 20_Min_Watts · 0.95 | W_per_kg = FTP / Rider_Weight_kg. Athletes who understand their numbers progress faster because they can separate programming from recovery — and the 247 result above is exactly that separator.
Most confusion about 20-Minute Functional Threshold Power (FTP) comes from mixing up the input you control with the input you merely observe. The formula treats them identically, but your decisions should not: one deserves measurement, the other deserves a defensible estimate.
What makes a calculation page trustworthy is that its copy is derived from its own arithmetic: here functional Threshold Power (FTP) = 247, recomputed every time a field changes, and the sensitivity section ranks the inputs that move the result — 20-Minute average power first, at ≈10.1 % of the headline for a ten-percent error either way in that input. Work down the page and by the end you could re-derive the result in a spreadsheet from memory.
The 20-Minute Functional Threshold Power (FTP) formula, explained
The engine implements a single stated model: FTP = 20_Min_Watts · 0.95 | W_per_kg = FTP / Rider_Weight_kg. There is no hidden coefficient and no login-gated precision — the formula printed is the formula executed, which is also what makes the result citable.
20-Minute average power (Watts) (example value 260) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. Replace the example with the figure from your own records — the tool recomputes instantly and the printed steps follow your numbers.
Rider body weight including kit (kg) (example value 72) is a quantity rather than a category — precision here is cheap and worth having. Use the same conditions each time (same scale, same time of day) so that changes in the output reflect real change.
The default 20-Minute Functional Threshold Power (FTP) calculation, written out in full
The tool prints its own working; this is the same arithmetic on the example values, reproduced so you can follow it by hand. Starting figures: 20-Minute average power (Watts), Rider body weight including kit (kg). Run to the end, the functional Threshold Power (FTP) resolves to 247 — <span style="color:#f59e0b;font-weight:700">● Cat 3 / Strong Club Rider</span>: 95% of 260W 20-min test average. on the bands this tool uses.
- 20-Minute All-Out Test Power = 260 Watts
- Coggan Protocol Deduction: FTP = 20-Min Watts × 0.95
- FTP = 260 × 0.95 = 247 Watts
- Power-to-Weight = 247 W ÷ 72 kg = 3.43 W/kg
- Sweet Spot Zone (88–94%) = 217 W to 232 W
Power-to-Weight Ratio — 3.43 W/kg. Read next to the headline, this is the figure that shows the shape of the trade-off.
Sweet Spot Training Range (88–94%) — 217 – 232 Watts. If your inputs change, this is usually the first companion figure to move.
Coggan Racing Category — Cat 3 / Strong Club Rider. Read next to the headline, this is the figure that shows the shape of the trade-off.
20-Minute Test Average — 260 Watts. Read next to the headline, this is the figure that shows the shape of the trade-off.
Hourly Calorie Burn at FTP — 886. Compare it against the main result of 247 before drawing conclusions.
Overwrite any input above and every line of this example updates with it — the substitution is live, not a screenshot of somebody else’s numbers.
The 20-Minute Functional Threshold Power (FTP) corridor: your result across a realistic band
Read this table as the practical error bar on the headline figure. It answers the question people actually have after seeing a single number: how wrong could this be if the main input is off by ten or twenty percent?
| 20-Minute average power setting | Functional Threshold Power (FTP) |
|---|---|
| 80 % of the example value | 198 |
| 90 % of the example value | 222 |
| example inputs | 247 |
| 110 % of the example value | 272 |
| 120 % of the example value | 296 |
Across 5 settings of 20-Minute average power, the result spans 198 to 296. A decision that only works at one row of this table is a decision waiting for an input to move. Reproduce it in the form above by editing 20-Minute average power alone; the substitution steps will follow your figures exactly.
Sensitivity: which inputs change 20-Minute Functional Threshold Power (FTP) the most
This list was computed for this specific engine just now: each numeric input was nudged ±10 % while every other field held its example value, and the functional Threshold Power (FTP) was recalculated from scratch. Read it as a map of where 20-Minute Functional Threshold Power (FTP) is fragile — drawn for the example inputs, which is the map you want when deciding what to measure carefully.
- 20-Minute average power: ten percent up gives 272, ten percent down gives 222 — ≈10.1 % of the functional Threshold Power (FTP) either way
20-Minute average power is the dominant lever here: ten percent either way moves the result by about 10.1 %, from 222 to 272. Spend your verification effort there first. The remaining fields can sit at safe defaults without materially changing the answer — knowing which is which is what separates a careful calculation from an anxious one.
Is your 20-Minute Functional Threshold Power (FTP) good — reading the result bands
Nobody acts on a bare figure — they act on a figure with a comparison attached. On the example inputs the band reads “<span style="color:#f59e0b;font-weight:700">● Cat 3 / Strong Club Rider</span>: 95% of 260W 20-min test average.”; your own figures place you on a different rung of the same ladder. Before treating the band as fact, note its width: ten percent either way on 20-Minute average power already spans 222 to 272. The practical reading rules: ask what would have to change to move you one band. If the answer is “a small, plausible input difference”, the band itself is not the finding — the uncertainty is.
Placing this figure in context: calculators of this kind differ less in arithmetic than in what they choose to ignore. This one keeps 20-Minute average power (Watts) explicit so that the omissions are visible rather than hidden in a preset.
Why 20-Minute Functional Threshold Power (FTP) results go wrong — and how to prevent it
Reading 20-Minute Functional Threshold Power (FTP) as a promise rather than a conditional. Every number here is of the form “if these inputs, then this result”; when an input moves, the honest response is to recompute rather than to defend the old figure.
Reading 20-Minute Functional Threshold Power (FTP) as a promise rather than a conditional. Every number here is of the form “if these inputs, then this result”; when an input moves, the honest response is to recompute rather than to defend the old figure.
One mistake is specific to this engine: assuming every input matters equally. The computation above shows 20-Minute average power dominating — a careful figure there beats false precision everywhere else.
Another is comparing across contexts: a 20-Minute Functional Threshold Power (FTP) computed with one set of conventions should never be lined up against a figure computed with another. Check the inputs behind both before ranking them.
Six things to confirm before acting on 20-Minute Functional Threshold Power (FTP)
- Record the date and the inputs alongside the number so future-you knows what was assumed.
- Check that every field the formula needs actually arrived from a document, not from recollection.
- Re-verify 20-Minute average power against a source document — ten percent of error there moves the headline by ≈10.1 %.
- Verify each input against its original source document, not memory.
- Compare the result with one independent method or published benchmark.
- Repeat the ±10 % test on the inputs that matter and see whether the decision — not just the number — still holds.
How to use the 20-Minute Functional Threshold Power (FTP) tool properly
Using a calculator well sounds trivial, but the difference between a decision-grade figure and a throwaway one lives entirely in the routine. The routine for 20-Minute Functional Threshold Power (FTP) takes a minute to learn and applies to every input above.
Step 1 — start from evidence. The inputs behind 20-Minute Functional Threshold Power (FTP) are 20-minute average power (watts), rider body weight including kit (kg). Write them down with their source next to each one; if you cannot name where a figure came from, that is the input most likely to be wrong. A figure with a date beside it becomes evidence; without one it stays an anecdote.
Step 2 — enter the conservative case first. Resist the flattering scenario. Type the inputs you would defend in front of a sceptical reader, read the Functional Threshold Power (FTP) (247 for the example values), and note the verdict band. The fastest sanity test is to guess the answer first and see how far the calculation disagrees.
Step 3 — change one input at a time. Nudge a single field by ten percent, watch the headline and its companions move, then undo it. Two or three fields will dominate — the sensitivity table above already ranks them for this engine. If the verdict changes with a ten-percent nudge, report the nudge alongside the number.
Step 4 — compute a corridor, not a point. Three runs — worst, likely, best — turn 20-Minute Functional Threshold Power (FTP) from a snapshot into a range. Plan against the pessimistic end and treat the optimistic end as the upside story. Most surprises in numbers are surprises about inputs, not about formulas.
Step 5 — save the story with the figure. A number without its inputs and its date is unusable within a quarter. Record 247, the assumptions behind it, and today’s date; your future self will be auditing a stranger’s arithmetic. A result worth acting on survives having its two shakiest inputs halved.
Who actually uses 20-Minute Functional Threshold Power (FTP) — and when
Fitness & Sports arguments end at arithmetic or they do not end. 20-Minute Functional Threshold Power (FTP) is the arithmetic: 247 on the example inputs, reproducible by anyone who types the same numbers. A result worth acting on survives having its two shakiest inputs halved.
The audience for this page is people who need one trustworthy number before their next decision. In professional Cycling practice the pattern is always the same — screen with 20-Minute Functional Threshold Power (FTP), then invest slow analysis only in whatever survives the screen. Comparisons are cheap: run the identical calculation for the alternative and look at the gap.
Nothing here is stored or transmitted, so the habit of checking is free: open the page, re-enter current figures, compare with the number you saved last time. Write the assumptions in the same file as the result, and future arguments take minutes instead of meetings.
20-Minute Functional Threshold Power (FTP) — frequently asked questions
What affects 20-Minute Functional Threshold Power (FTP) the most?
Measured on this engine, 20-Minute average power is the dominant lever: moving it ±10 % shifts the functional Threshold Power (FTP) across 222 to 272 — about 10.1 % of the headline. The ranked list in the sensitivity section is computed live, not asserted from a template.
What is a typical 20-Minute Functional Threshold Power (FTP)?
With the example inputs on this page the result is 247, labelled “<span style="color:#f59e0b;font-weight:700">● Cat 3 / Strong Club Rider</span>: 95% of 260W 20-min test average.”. “Typical” varies with situation, which is why every result here ships with its verdict band and its sensitivity list: they turn one figure into a range you can locate yourself inside.
How do I calculate 20-Minute Functional Threshold Power (FTP) by hand?
FTP = 20_Min_Watts · 0.95 | W_per_kg = FTP / Rider_Weight_kg is the entire method. Work the inputs in that order — 20-Minute All-Out Test Power = 260 Watts — and you will reach 247 on the default figures, the same number this tool prints.
What happens to 20-Minute Functional Threshold Power (FTP) if 20-minute average power changes by 10 %?
The engine was re-run with that field moved by ten percent while everything else stayed fixed: the functional Threshold Power (FTP) goes across 222 to 272, a swing of roughly 10.1 % around the 247 baseline. That ratio is the practical definition of how much this input matters.
Is the 20-Minute Functional Threshold Power (FTP) result of 247 good or bad?
The tool answers “what”, not “whether”: 247 carries the verdict “<span style="color:#f59e0b;font-weight:700">● Cat 3 / Strong Club Rider</span>: 95% of 260W 20-min test average.” for the default case, which is a starting interpretation rather than a verdict on your situation. Re-run with your own figures and compare the bands.
Can 20-Minute Functional Threshold Power (FTP) be negative or empty?
Yes, and that is informative rather than broken: a negative 20-Minute Functional Threshold Power (FTP) usually means the inputs encode an outflow or a shortfall, and the verdict band above labels exactly that situation instead of hiding it.
How do I calculate 20-Minute Functional Threshold Power (FTP) manually?
Write down the inputs, then follow the printed steps in order — FTP = 20_Min_Watts · 0.95 | W_per_kg = FTP / Rider_Weight_kg. A spreadsheet replicates it with two or three cells. The manual route is worth doing once to build intuition; after that the calculator saves time and eliminates transcription slips.
Why do we deduct 5% from the 20-minute test?
During a 20-minute effort, approximately 5% of total power output is derived from anaerobic glycolysis and the phosphagen energy system. Subtracting 5% removes the anaerobic contribution to accurately estimate true 60-minute aerobic steady-state threshold.
Is my data private on this page?
Yes — computation happens locally in your browser, with no account, no tracking of your inputs and nothing sent to a server. The printed formula is the whole story of what happens to your figures.
The vocabulary of 20-Minute Functional Threshold Power (FTP)
- Power-to-Weight Ratio
- 3.43 W/kg in the default 20-Minute Functional Threshold Power (FTP) calculation — one of the secondary figures an experienced reader checks before trusting the primary number.
- Sweet Spot Training Range (88–94%)
- 217 – 232 Watts in the default 20-Minute Functional Threshold Power (FTP) calculation — one of the secondary figures an experienced reader checks before trusting the primary number.
- Coggan Racing Category
- Cat 3 / Strong Club Rider for the 20-Minute Functional Threshold Power (FTP) worked case; it sits next to the main result because it carries context the headline leaves out.
- Functional Threshold Power (FTP)
- The primary output of this tool: 247 for the default inputs, computed exactly from FTP = 20_Min_Watts · 0.95 | W_per_kg = FTP / Rider_Weight_kg.
- Worked example
- The step-by-step substitution printed above, so the arithmetic can be re-derived by hand or in a spreadsheet.
- Verdict band
- The plain-language label — here “<span style="color:#f59e0b;font-weight:700">● Cat 3 / Strong Club Rider</span>: 95% of 260W 20-min test average.” — mapping the computed figure onto experience-based ranges for Fitness & Sports.
- Sensitivity (±10 %)
- How far the 20-Minute Functional Threshold Power (FTP) moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
Methodology, sources and limits
The model is published arithmetic implemented exactly as written: FTP = 20_Min_Watts · 0.95 | W_per_kg = FTP / Rider_Weight_kg. Source of record: Allen H, Coggan A. "Training and Racing with a Power Meter." VeloPress 2010. Specialist software layers extra coefficients on top of the same algebra; none are hidden here, and that transparency is what makes a disagreement traceable to a specific input instead of a black box.
Treat the output as a precise answer to the question you typed: exact arithmetic, transparent formula, published source, no hidden rounding. Nothing is smoothed, weighted or adjusted behind the scenes; where judgement enters, this page says so and names the input responsible.
Turning this 20-Minute Functional Threshold Power (FTP) into a decision
Re-run the calculation with your own figures, stress the two most sensitive inputs by ±10 %, and only then act on the result.
This page was written for people who need one trustworthy number before their next decision, and the promise is that nothing above required trust. Bookmark the tool, re-run it whenever an input moves by more than a few percent, and keep the date with the number.