WattsUP — year-round cycling training and ride log
Build it indoors.
Spend it on the road.
WattsUP runs ERG intervals on your smart trainer, reads the FIT files from your head unit, and puts every ride on one fitness curve. No ads. No feed. Export everything, any time.
Training load
One fitness curve, indoors and out.
Chronic load, acute load and form, plotted across the whole season instead of resetting when the weather turns. February’s trainer base still counts in June, because your legs don’t know the difference. New to the numbers? Read how training load actually works.
Model your training loadYou went out 38 W over threshold on the first steep ramp and paid for it on the next. Same climb, best day: 12 W under.
Ride analyzer
Every climb, ramp by ramp.
Drop a GPX, FIT or TCX file and it’s parsed, deduplicated and charted before your shoes are off. Each climb splits into ramps with grade and VAM, laid against the same climb on your better days. Every road you ride builds a personal heatmap, too.
Explore the ride analyzerSmart trainer
ERG workouts that read your form.
Structured intervals that adjust to your actual TSB instead of a plan written for somebody else. ERG mode over Bluetooth or ANT+, with live power, cadence and heart rate on screen. Group rides with real people and no bots padding the field.
See every featureYour rides stay yours.
In November 2024, Strava changed its API terms so third-party apps could no longer show your activity data to anyone but you, which broke coach access on platforms like Intervals.icu overnight.
If your riding history lives on someone else’s platform, its terms can change on a Tuesday. WattsUP works the other way round.
Read the full data commitmentExport everything
Your files import from anywhere and export to anywhere, in full, any time. No argument.
No ads, ever
There is no ad product and there is no plan for one.
No feed
No algorithm decides what you should see.
Not training data
Your rides are not training material for anything.
Small pack.Real riders.
WattsUP is a small community of riders, not a platform with a growth team. It’s built by one cyclist who wanted the trainer winters and the road summers in the same logbook, and got tired of every app trying to sell him something. Group rides are real people with no bots, so you’ll start recognising names quickly. If you want a virtual world with tens of thousands of riders, that’s Zwift, and it’s good at that. This is the other thing: your rides and your numbers, kept properly, all year.
Questions
What ride file formats does WattsUP support?
WattsUP supports drag-and-drop import for standard cycling files including GPX, FIT, and TCX formats exported from Garmin, Wahoo, Tacx, Hammerhead, and Strava. Files are parsed, deduplicated, and charted on your personal Sun Log instantly.
Does WattsUP connect to indoor smart trainers?
Any trainer supporting Bluetooth FTMS or ANT+ FE-C pairs directly, which covers Wahoo, Tacx, Elite, Saris, JetBlack, and Zwift Hub. You get structured ERG mode interval workouts, live power and cadence on screen, and bot-free group rides.
How does WattsUP calculate Training Load and TSB?
WattsUP calculates Chronic Training Load (CTL), Acute Training Load (ATL), and Training Stress Balance (TSB) using the Banister impulse-response model. Your numbers carry straight through from the trainer months into summer road miles, so winter base still counts in July.
Can I install WattsUP on mobile or desktop?
Yes. WattsUP is a Progressive Web App (PWA) that runs directly in your browser and installs to your home screen or desktop on iOS, Android, macOS, and Windows. There is no app store download and no update to chase.
Is my cycling data private and exportable?
Yes. Your ride data belongs to you. There are no advertising algorithms, no sponsored brand posts, and no public feeds forced on your training. You can export your full dataset at any time.
What does WattsUP cost?
WattsUP is completely free. I want to make this app free until I can't pay the hosting cost any longer. For the time being, there are no subscription fees, no locked features, and no credit card required.
How is WattsUP different from Zwift?
Zwift is a virtual world you race in, with tens of thousands of riders online at any hour. WattsUP is a training log and workout player with a small group-ride feature. If you want immersive virtual racing, Zwift does it better. If you want your indoor and outdoor rides in one training-load model that you fully own and can export, that's what WattsUP is for.
Can I use WattsUP alongside Strava?
Yes. Export a FIT or GPX file from Strava and import it, or upload the original file from your head unit to both. WattsUP does not require a Strava connection and does not depend on Strava's API.
Which smart trainers does WattsUP work with?
Any trainer supporting Bluetooth FTMS or ANT+ FE-C, which covers current models from Wahoo, Tacx, Elite, Saris, JetBlack, and Zwift Hub. Power meters, heart rate straps, and cadence sensors pair over the same protocols.
Do I need to install anything?
No. WattsUP is a Progressive Web App that runs in the browser and installs to your home screen or desktop on iOS, Android, macOS, and Windows. There is no app store download and no update to chase.
Can I export my data and leave?
Yes, in full, at any time, without emailing anyone. Your rides export as the original files plus a structured archive of every metric WattsUP has calculated. Account deletion removes everything.