How To Find Your FTP While Sitting On The Couch

If you have ridden hard at any point in the last 90 days, you have already done your FTP test. You just did not call it one. The effort is sitting in your ride files, second by second, and it takes about three minutes to get the number out of it. No test to dread, no account to make, nothing uploaded anywhere.

Go straight to the calculator

Key takeaways

• If you have ridden hard in the last 90 days, your FTP is already sitting in your ride files. No test needed.
• You need four or five rides, not ninety days of them. Your best 20 minutes came from a handful of hard days and you probably know which ones.
• The calculator is free, needs no account, and runs entirely in your browser. Your ride files never leave your computer.
• It gives you FTP, threshold heart rate, and your full power and heart rate zones, ready to print.
• It also tells you whether it thinks your effort was genuinely flat out, which most calculators will not.

Nobody enjoys an FTP test

Let us be honest about this. Almost no rider I have ever coached looks forward to a threshold test. It sits in the calendar all week. People shuffle it to Thursday, then to the weekend, then quietly to next month. Some never do it at all, and end up training off a number they set eighteen months ago, or one the app guessed for them.

Which is a problem, because your FTP is the number every single one of your training zones is built on. If it is wrong, every ride you do afterwards is the wrong intensity. Not dramatically wrong, just quietly wrong, over and over, for months.

So here is the thing I wish more riders knew. If you have ridden hard at any point in the last three months, you have already done the test. You just did not call it that.

That hilly loop where you buried yourself on the long drag. The club 10. The group ride where it went nuclear on the way home and you hung on. Every one of those efforts got recorded, second by second, by your head unit. The number is in there. All that is missing is something to dig it out.

So I built something to dig it out

The Ride Harder FTP calculator takes your ride files and finds your best sustained efforts across the last 90 days. From those it works out your threshold power, your threshold heart rate, and your full set of training zones.

It is free. There is no account to make. And, importantly, it runs entirely inside your web browser. Your ride files are read on your own computer and never get uploaded anywhere, including to me. I have no interest in storing your training data and you should be wary of any free tool that does.

Find your FTP now

Why bother, if I could just guess?

Because most riders are working from a number that is wrong, usually in the same direction.

Ramp tests flatter you. They are quick and popular and hard to pace badly, which is exactly why so many apps default to them. But a ramp rewards anaerobic power and raw muscular strength as much as aerobic fitness. A rider who is strong in the gym but aerobically underdone can post a ramp number they could not hold for fifteen minutes, let alone an hour.

An inflated FTP is worse than no FTP. Every zone shifts up underneath it. Your sweet spot becomes threshold. Your threshold intervals become efforts you cannot finish. Your easy rides stop being easy. You end up permanently slightly too tired and unable to work out why a perfectly sensible plan is producing nothing.

Old numbers go stale in both directions. Fitness moves. If you have had a good winter your number is low and you are training too easy. If you have had six months off it is high and you are digging a hole.

I am not interested in giving you the highest possible number. Anyone can do that, and plenty of platforms will. I am interested in giving you the most accurate one, because that is the only version that is any use to you.

How to use it, step by step

Three routes in, depending on what you have. Pick whichever fits.

Option 1: you pay for Strava

You may not need the calculator at all. Strava subscribers get a Power Curve, and it will hand you an estimate directly.

1. Open Strava on a computer, not the phone app.
2. Hover Training in the top menu and choose Power Curve.
3. Set the date range to the last 90 days.
4. Tick Show Estimated FTP.

That dotted line is Strava's guess. It is a fair starting point. Be aware that plenty of riders find it reads high, for the same reason ramp tests do, so it is worth cross-checking against a number built from a real sustained effort. Which is what the calculator does.

Option 2: export a handful of hard rides (this is the one I would use)

Works on a free Strava account, on Garmin Connect, on Wahoo, on anything. Takes about three minutes.

Pick your rides first. You want four to six of your hardest rides from the last 90 days. Not all of them. The ones that hurt. Time trials, hilly rides, hard chain gangs, that race you did in June. If you are scrolling and thinking "that one was horrible", that is the one you want.

From Strava:

1. Open one of those rides on a computer.
2. Click the ... menu just under the ride title.
3. Choose Export Original. That downloads the untouched file from your head unit, with every watt and heartbeat in it.
4. Repeat for each ride. Around thirty seconds each.

From Garmin Connect:

1. Open the activity on a computer.
2. Click the gear icon top right.
3. Choose Export to FIT, or export the original file.

Then go to the calculator and drag all of those files onto the page at once. That is it. The numbers appear in about a second.

Option 3: you want the full 90 days

If you would rather be thorough, Strava will give you everything you have ever uploaded.

1. On strava.com, go to Settings, then My Account.
2. Under Download or Delete Your Account, click Get Started, then Request your archive.
3. Wait. It arrives by email, usually within a few hours.
4. Drop the whole ZIP file onto the calculator. It picks out the recent rides itself.

Two warnings. It is your entire history, so it can be a big download. And the link expires after about a week, so grab it when it lands.

Honestly, option 2 gets you the same answer in a fraction of the time. Your best 20 minutes came from one of those hard rides, not from the Tuesday recovery spin.

What you get back

Your FTP, in watts, with a plain explanation of which ride it came from and what you held.

Your threshold heart rate, taken from the heart rate during that exact same 20 minute effort. That is the bit I am quietly pleased with. It is a proper 20 minute test, found after the fact, rather than a guess based on your age.

Your full training zones, both power and heart rate, in a table you can print or save as a PDF and stick on the shed wall.

An honest read on whether to trust it. This is the part that makes it different. The calculator compares your 20 minute effort against the shape of your whole power curve. If your shorter efforts suggest you had plenty more in you, it will tell you the number is reading low and send you off to do one proper effort. If your best 20 minutes came from a surgy group ride rather than a steady effort, it will tell you to treat the number as a ceiling.

I would rather the tool told you it was unsure than quietly handed you a number that was wrong. That is the whole point of it.

What to work on next. It also compares your threshold against your five minute power. If your threshold is a long way below your ceiling, you have room to push threshold up. If it has nearly caught your ceiling, more threshold work will not move much and you need to raise the roof instead. Two different riders, two completely different next blocks.

A couple of honest caveats

These are guidelines, not gospel. They get you close, which is a great deal better than where most riders are starting from. Zones are a starting point for training, not a score to defend. Every platform carves them up slightly differently, so if your head unit disagrees by a few watts, do not lose any sleep over it.

Heart rate lags, and it lags badly. It takes two to three minutes to catch up with what your legs are doing. On anything short and hard, your power is finished before your heart rate has arrived. You can ride a genuinely maximal VO2 effort and never once see a zone 5 number on your head unit. That is not you failing the effort, it is the metric turning up late. Use heart rate for steady riding and power or feel for anything under about five minutes.

No power meter? You can still do this. Drop in rides with heart rate and you will get your threshold heart rate and your heart rate zones. Less precise than power, but a long way better than guessing.

Then do the important bit

Knowing your zones is step one. Training in them is step two. Step one takes three minutes and most riders never do it properly, then wonder why step two is not working.

Get the number. Print the zones. Then go and use them. I have put three free sessions up as Zwift and TrainingPeaks downloads, all written as percentages of your FTP, so they will scale to whatever number you just found.

Find your FTP without doing a test

If you want a hand turning those zones into an actual plan, that is exactly what I do. Take a look at 1:1 coaching, or have a read of how to calculate your FTP and what counts as a good number.

Coach James