Intervals.icu vs TrainingPeaks Compared
By Toby Pattullo
Australian Deaflympic marathon and ultra runner, and the solo developer behind IcuSync.
What each platform is actually for
TrainingPeaks was built for the coach and athlete relationship. It has a large coaching marketplace, a library of training plans from professional coaches, structured workout creation, and fitness tracking through its TSS and CTL model. If you are working with a coach who uses TrainingPeaks, it is likely the right tool for that relationship. The premium tier costs $19.95 per month.
Intervals.icu was built by David Tinker, a single developer, as a serious training analytics tool for athletes who want to understand their own data. It is completely free. It includes fitness and fatigue tracking, structured workout building, zone analysis, pace and power analytics, and automatic sync to Garmin, Coros, Wahoo, Polar, Suunto, Amazfit, Zwift, and other devices. It does not have a social feed. It does not have a coaching marketplace. It is a data tool, and it is very good at being a data tool.
Cost comparison
Intervals.icu is free with no premium tier. Everything is available to every user.
TrainingPeaks has a free tier with limited features. The premium tier is $19.95 per month, around $240 per year.
Feature comparison
| Feature | Intervals.icu | TrainingPeaks |
|---|---|---|
| Cost | Free | $19.95/month |
| Fitness and fatigue (CTL/ATL/TSB) | ✓ Yes | ✓ Yes (Premium) |
| Structured workout builder | ✓ Yes | ✓ Yes |
| Planned workout push to Garmin | ✓ Yes | ✓ Yes |
| Planned workout push to Wahoo | ✓ Yes | ✓ Yes |
| Planned workout push to Coros | ✓ Yes | ✓ Yes |
| Planned workout push to Suunto | ✓ Yes | ✓ Yes |
| Planned workout push to Amazfit | ✓ Yes | ✓ Yes |
| Planned workout push to Polar | ✕ No* | ✕ No |
| Planned workout push to Apple Watch | ✕ No* | ✓ Yes (via app) |
| Planned workout push to Zwift | ✓ Yes | ✓ Yes |
| Completed workout sync from Huawei | ✓ Yes | ✕ No |
| Zone analysis | Yes, detailed | ✓ Yes |
| Open API access | ✓ Yes, free | Limited |
| Coach and athlete platform | ✓ Yes, via invite | ✓ Yes, with marketplace |
| AI integration via IcuSync | ✓ Yes | ✕ No |
| Third-party app integrations | 250+ | 100+ |
| Free to use | ✓ Yes, fully | ✕ No |
Polar and Apple Watch users: Intervals.icu cannot push planned workouts to these devices due to platform restrictions. Completed workouts still sync back automatically. Apple Watch users can use the third-party Watchletic app as a workaround.
TrainingPeaks "completed only" devices: For Polar, TrainingPeaks only receives completed workouts uploaded from the device. Planned structured workouts are not pushed back to the watch.
Where Intervals.icu wins
For self-coached athletes who want to understand their training data, Intervals.icu is in a different league. The fitness and fatigue modelling is detailed, the zone distribution tools are genuinely useful, and the open API means developers can build on top of it in ways that are not possible with a closed platform.
The price is also hard to argue with. You get more analytical depth than TrainingPeaks Premium for free.
Device sync is a significant Intervals.icu advantage. Planned structured workouts push directly to Garmin, Coros, Wahoo, Suunto, and Amazfit automatically, and all for free. TrainingPeaks supports most of these devices too but requires a paid subscription. Where Intervals.icu has a clear edge is the open API, 250+ third-party integrations, and the fact that everything is completely free.
Intervals.icu also integrates with over 250 third-party apps via its open API, compared to around 100 for TrainingPeaks. The ecosystem around Intervals.icu is growing fast precisely because the API is free and open.
Where TrainingPeaks wins
If you have a coach or want access to professionally designed training plans, TrainingPeaks is the better choice. Its coaching marketplace is mature, the plan library is extensive, and many professional coaches use it as their primary tool. Intervals.icu does support coach and athlete connections but does not have a marketplace where you can browse and hire coaches directly.
Do you have to choose?
No. Many athletes use TrainingPeaks for a coaching relationship and Intervals.icu for personal analysis. Intervals.icu also works alongside the other apps you already use, including Strava, so you can keep sharing your activities there.
What about AI and training data?
This is where Intervals.icu has a meaningful advantage that did not exist a year ago. Because Intervals.icu has a free and open API, it is possible to connect AI tools directly to your training data.
IcuSync connects Claude, Anthropic's AI assistant, directly to your Intervals.icu account. Once connected, Claude can read your training history, fitness and fatigue trends, and activity details, then have a genuine coaching conversation with you about what the data means. It can also build structured workouts and push them directly to your calendar, where they sync automatically to your Garmin, Coros, Wahoo, Polar, Suunto, Amazfit, Zwift, or other device.
IcuSync costs $20 USD per year. Intervals.icu remains free.
Which platform should you use?
If you are self-coached and want serious training analytics with no subscription fee, start with Intervals.icu. It is free and it connects to your existing devices.
If you work with a coach, check what platform they use. If it is TrainingPeaks, use TrainingPeaks for that relationship and consider adding Intervals.icu alongside it for personal analysis.
IcuSync connects Claude AI to your Intervals.icu data. Ask questions about your training, build workouts, and push them straight to your watch.