What is FTP in cycling?

FTP, or Functional Threshold Power, is the highest average power in watts you can sustain for about an hour. It is the anchor for every power-based training plan because almost all workouts are prescribed as a percentage of it. A rider with an FTP of 250 W can hold roughly 250 W for 60 minutes; above that, lactate accumulates faster than the body clears it and the effort falls apart. Knowing your FTP lets you set honest interval targets instead of guessing.

How does the 20-minute test estimate FTP?

You warm up, then ride a maximal, evenly paced 20-minute effort and record the average power. A full-hour all-out test is brutal, so Coggan's shortcut multiplies the 20-minute average by 0.95. The 5% haircut accounts for the fact that you can push harder over 20 minutes than over a full hour. Example: a 20-minute average of 280 W gives an FTP of 280 × 0.95 = 266 W. Pace it like a time trial, not a sprint that blows up at minute five, or the estimate runs high.

What are the 7 Coggan power zones?

Andrew Coggan's classic model splits effort into seven levels set as percentages of FTP: Z1 active recovery (under 55%), Z2 endurance (55-75%), Z3 tempo (75-90%), Z4 lactate threshold (90-105%), Z5 VO2max (105-120%), Z6 anaerobic capacity (120-150%) and Z7 neuromuscular sprint (over 150%). Each zone trains a different system. At an FTP of 250 W, Z2 endurance lands at roughly 138-188 W and Z5 VO2max at 263-300 W, so the same ride feels completely different depending on which band you hold.

What is a good watts per kg for cycling?

Watts per kilogram is FTP divided by body weight, and it matters most on climbs where you fight gravity. Rough male brackets: under 2 W/kg untrained, 2-3 recreational, 3-4 a solid club rider, 4-5 a strong amateur racer, and over 5 W/kg approaches elite. Women's thresholds sit a little lower for the same labels. Example: 250 W on a 70 kg rider is about 3.6 W/kg, a good club level. On the flat, raw watts win; the moment the road tilts up, W/kg is what drops you or keeps you on the wheel.

What happens in Zone 2 endurance training?

Z2 sits at 55-75% of FTP and is the aerobic base most weekly hours should live in. At this intensity you can hold a full conversation, fat oxidation is high, and you build mitochondrial density and capillary networks without deep fatigue. It feels almost too easy, which is exactly why riders skip it and ride everything at a grey medium-hard pace that improves nothing. A polarized plan keeps roughly 80% of time in Z1-Z2 and saves the hard 20% for Z4-Z5 intervals.

How often should I re-test my FTP?

Re-test every four to six weeks during a focused training block. FTP rises as fitness improves, and stale zones quietly make every workout too easy. If your threshold intervals start feeling comfortable or your heart rate no longer reaches the same level at the same watts, that is your cue to re-test. Use the same protocol each time, warmed up and rested, so the numbers are comparable. Many riders also use a 20-minute power PR on a known climb as an informal check between formal tests.

Set your zones after a 20-minute test

You just finished a brutal 20-minute effort and your head unit reads 280 W average. Type that in, the tool returns an FTP of 266 W and the full Coggan zone chart in watts. Now your Z4 threshold intervals have a real target instead of "go hard", and your Z2 base rides have a ceiling so you actually keep them easy.

Build a structured interval workout

Your plan says "4 × 8 min at threshold". With your zones in front of you, Z4 reads 239-279 W at an FTP of 266. You set the workout target to the middle of that band, load it onto the trainer, and the session is unambiguous. Copy the whole table into your training log so next week's numbers compare against the same reference.

Compare two riders on a climb

One rider holds 300 W at 85 kg, another 250 W at 65 kg. Raw watts say the first is stronger, but the calculator shows 3.53 versus 3.85 W/kg. On a long climb the lighter rider pulls away despite fewer watts. Use the W/kg readout before you pick who leads up the next mountain.

Track fitness across a training block

Re-test every four to six weeks, drop the new 20-minute number in, and watch FTP climb from 250 to 270 to 285 W. Each re-test rebuilds every zone automatically, so your interval targets stay honest instead of drifting too easy as you get fitter. Share the link with your coach to show exactly where the zones landed.

Cycling FTP Calculator — Power Zones and Watts per Kg

20-min power × 0.95 = FTP — Coggan 7 power zones, watts and W/kg, one-click copy — runs in your browser

Runs locally
Category Calculator
Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.

How do you know your number

20-min average power

Average watts from an all-out 20-minute effort. The tool takes 95% of it as your FTP.

Body weight

Add your weight to see W/kg — the number climbers actually compare.

Sex

Your FTP

266

Power-to-weight

3.80

W/kg · Roughly good club rider

Coggan power zones

Zone	% FTP	Watts	What it trains
Z1 Active recovery	0–55%	0–146	Easy spinning, recovery rides, warm-up and cool-down.
Z2 Endurance	55–75%	146–200	The aerobic base. Long steady rides; most weekly hours live here.
Z3 Tempo	75–90%	200–239	Sustained "comfortably hard" tempo work, sweet-spot edge.
Z4 Lactate threshold	90–105%	239–279	Right around FTP. 8-30 min intervals that raise the threshold itself.
Z5 VO2max	105–120%	279–319	Hard 3-8 min intervals targeting maximal oxygen uptake.
Z6 Anaerobic capacity	120–150%	319–399	Short 30s-2min efforts for repeated-attack and anaerobic capacity.
Z7 Neuromuscular	150%+	399+	All-out sprints under 30s, neuromuscular power and bike-handling snap.

Z1 Active recovery

Easy spinning, recovery rides, warm-up and cool-down.

Z2 Endurance

The aerobic base. Long steady rides; most weekly hours live here.

Z3 Tempo

Sustained "comfortably hard" tempo work, sweet-spot edge.

Z4 Lactate threshold

Right around FTP. 8-30 min intervals that raise the threshold itself.

Z5 VO2max

Hard 3-8 min intervals targeting maximal oxygen uptake.

Z6 Anaerobic capacity

Short 30s-2min efforts for repeated-attack and anaerobic capacity.

Z7 Neuromuscular

All-out sprints under 30s, neuromuscular power and bike-handling snap.

FTP is a 20-30 min field estimate, not a lab number. Re-test every 4-6 weeks; your zones shift as fitness changes. The 20-minute × 0.95 formula assumes a true all-out effort — pace it like a time trial, not a sprint that fades.

What this tool does

Free cycling FTP calculator that turns a 20-minute test or a known Functional Threshold Power into your full set of Coggan training zones. Enter the average watts from an all-out 20-minute effort and the tool takes 95% of it as your FTP, the standard estimate of the power you could hold for an hour. From that single number it builds all seven Coggan power zones in watts: Z1 active recovery, Z2 endurance, Z3 tempo, Z4 lactate threshold, Z5 VO2max, Z6 anaerobic capacity and Z7 neuromuscular sprint. Add your body weight and it reports watts per kilogram, the number climbers actually compare, plus a rough fitness bracket adjusted for men and women. Already know your FTP from a head unit or coach? Switch to the direct-input mode and skip the test math. Every zone range is contiguous so there are no gaps, copy the whole table to your training log with one click, and share the link to reopen the exact same zones. 100% client-side, nothing leaves your browser.

Tool details

Input: Numbers; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy + Preview; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 9 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Calculator · Content Creator; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How Cycling FTP Calculator fits into your work

Use it for fast estimates, comparisons, and planning numbers before you make the final call.

Calculation jobs

Getting a realistic range before a purchase, plan, workout, or schedule decision.
Comparing scenarios by changing one input at a time.
Turning rough assumptions into a number you can discuss.

Calculation checks

Double-check units, dates, rates, and rounding assumptions.
Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
Save the inputs that produced an important result so you can reproduce it later.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Set your zones after a 20-minute test
You just finished a brutal 20-minute effort and your head unit reads 280 W average. Type that in, the tool returns an FTP of 266 W and the full Coggan zone chart in watts. Now your Z4 threshold intervals have a real target instead of "go hard", and your Z2 base rides have a ceiling so you actually keep them easy.
Build a structured interval workout
Your plan says "4 × 8 min at threshold". With your zones in front of you, Z4 reads 239-279 W at an FTP of 266. You set the workout target to the middle of that band, load it onto the trainer, and the session is unambiguous. Copy the whole table into your training log so next week's numbers compare against the same reference.
Compare two riders on a climb
One rider holds 300 W at 85 kg, another 250 W at 65 kg. Raw watts say the first is stronger, but the calculator shows 3.53 versus 3.85 W/kg. On a long climb the lighter rider pulls away despite fewer watts. Use the W/kg readout before you pick who leads up the next mountain.
Track fitness across a training block
Re-test every four to six weeks, drop the new 20-minute number in, and watch FTP climb from 250 to 270 to 285 W. Each re-test rebuilds every zone automatically, so your interval targets stay honest instead of drifting too easy as you get fitter. Share the link with your coach to show exactly where the zones landed.

Common pitfalls

Sprinting the 20-minute test instead of pacing it. A test that starts at 350 W and fades to 220 W produces an inflated average and an FTP you can never actually hold. Ride it like a time trial — even effort start to finish — or the whole zone chart sits too high and every interval feels impossible.
Confusing the 20-minute average with FTP itself. The 280 W you held for 20 minutes is NOT your FTP; FTP is 95% of it, here 266 W. Skipping the 0.95 step sets every zone about 5% too high, so your Z2 base rides creep into tempo and quietly wreck your recovery.
Forgetting to re-test after a training block. Zones built on a 250 W FTP from two months ago make a now-fitter rider train too easy. If threshold intervals feel comfortable, the number is stale — re-test and let the tool rebuild every zone around the new FTP.

Privacy

Every number here — the FTP formula, the seven zone ranges, the watts per kilogram and the fitness bracket — is plain JavaScript that runs inside your browser tab. Your power, weight and sex never reach a server and nothing is logged. The one caveat: the shareable URL encodes your inputs in the query string, so a link pasted into chat records those values in the recipient server's access log. If your weight is private, use the copy button and paste the zone table as text rather than sharing the URL.

FAQ

Tool combos

Folks in your role tend to reach for these alongside this tool.

Content Creator

Browse all tools for this role

Cycling FTP Calculator — Power Zones and Watts per Kg

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How Cycling FTP Calculator fits into your work

Calculation jobs

Calculation checks

Good next steps

Real-world use cases

Set your zones after a 20-minute test

Build a structured interval workout

Compare two riders on a climb

Track fitness across a training block

Common pitfalls

Privacy

FAQ

Unit Converter

Percentage Calculator

VO₂max Calculator

Running Pace Calculator

Heart Rate Zones Calculator

24-Point Solver & Game

555 Timer Calculator

A1C to Blood Glucose Calculator

Add Days to Date Calculator

Age Calculator

Age Difference Calculator

AI Token Counter