Plan it big. Ride it small.

Climb, wind on every stretch, your tyres and your position, solved on a big map in any browser. It's on your phone before you clip in. Free.

Free in any browser, with the account you use in the app. · Get the app for the ride →

Free, paid for by ads. Nothing to buy. · No account needed.

More room at a desk.

Everything you set up here is on your phone at the next sync.

  • The Kardiacs workout builder: a smart workout's shape drawn in zones and resolved to a critical power of 250 W, above the name, sport and first block

    Workout builder

    Blocks of a zone, not fixed watts. They resolve to your fitness when you ride.

  • Training load in the Kardiacs web planner: fitness as a 42-day average against fatigue as a 7-day one over a month, and the power curve with its critical-power fit below

    Fitness and fatigue

    Your training load and power curve, month by month.

  • One ride analysed in the Kardiacs web planner: duration, distance, climb, power and heart-rate numbers, the elevation profile and the power trace

    Every ride, analysed

    Power, heart rate, cadence and climb, with every chart scrubbable.

  • Kit in the Kardiacs web planner: a road bike, an indoor trainer and running shoes, each with its weight and paired sensors

    Your kit

    Every bike’s weight and sensors, so the planner’s numbers are yours.

Everything else the ride needs.

Got 45 minutes? Here’s your loop.

  • Loops from your door, sized to your time
  • Every turn called, on maps for anywhere on Earth. No signal needed
  • Wandered too far? Tap back — home by the time you set
  • The weather, wind and air quality you’re heading into
Loop options in Kardiacs, each with its distance, time, climb and effort laid out
Directions in Kardiacs: a route to a dropped pin drawn on the map, with its distance, time and climb

You pedal. It sets the watts.

  • ERG control of your smart trainer
  • Workouts scaled to your fitness, indoors and out
  • Build your own, down to the interval
  • On your wrist with Apple Watch. A mix matched to every interval’s cadence (iPhone)
An indoor ride ready to start in Kardiacs, with the trainer and power meter connected and the target power shown
Structured indoor rides sorted by intensity, with interval charts and target power

Rest day or hard day? It knows.

  • Readiness from sleep, HRV and stress
  • Every session analysed — power, pace, zones
  • Fitness and fatigue over time
A daily readiness recommendation in Kardiacs, based on recent sleep, HRV and stress
A session summary in Kardiacs: pace chart, splits, and time in each zone

Saturday’s better with everyone on it.

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Why is it free?

Free, paid for by ads. Nothing to buy. The ads pay for the maps and servers.

Ride in a minute.

  1. Download. No account, no sign-up wall.

  2. Tell it your age and weight — or connect Health — for zones from day one.

  3. Pick Explore, Commute or Indoor. Go.

Bringing history? Import your Strava or Garmin archive, or any FIT file.

Questions

Is it really free?

Yes. Ads pay for the maps and servers. There is no paid tier and nothing to buy.

Do my friends need the app too?

Yes — it is phone to phone. They join by scanning your QR code, with no account. Riders can be up to 200 m apart, and further as phones relay it along the group.

Does it work on Android?

Yes. The map, chat and photos work between any phones running Kardiacs. Group voice works iPhone to iPhone (iPhone 12 or later, iOS 26.4+) and Android to Android (Android 13+ with Wi-Fi Aware).

Does it work with my trainer, watch or bike computer?

Bluetooth FTMS and Wahoo smart trainers, power meters and heart-rate straps pair directly. There is an Apple Watch app. Routes and workouts go out to your bike computer, and the rides it records come back in.

Do I need an account?

No. There is no sign-up wall. Sign in with Google or Apple only when you want your history, routes and gear to follow you between devices and into the web planner.

More questions, answered →

Saturday’s better with everyone on it.

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