Intervals.icu vs TrainingPeaks: Free Analytics or the Industry Standard in 2026?

TL;DR: Intervals.icu vs TrainingPeaks is one of the most common platform questions in endurance sport. In our view, self-coached athletes who want analytics are best served by Intervals.icu: the fitness chart, power curve and interval analysis are in its free tier, with an optional Supporter tier at 4 USD per month (Intervals.icu pricing). On TrainingPeaks, athletes need Premium to see charts such as the Performance Management Chart and the Power Profile themselves (TrainingPeaks charts), at 19.95 USD per month or 134.99 USD per year before tax (TrainingPeaks for athletes, sales tax). For coached athletes and coaches who want reach, TrainingPeaks has the larger ecosystem: a Training Plan Marketplace that sold 70,000+ plans in 2023 (TrainingPeaks for coaches), a coach network through Coach Match (Coach Match) and national federations among its partners (TrainingPeaks partners). For physiological testing, we did not find a way in the documentation of either platform to analyze a lactate step test and derive LT1 and LT2 from it. That is where Coachbox comes in, a coaching platform built around lactate testing: it detects LT1 and LT2 automatically in under a minute, turns the result into zones, and runs the workflow from test to training around it, with in-app messaging between coach and athlete and Coachbox AI as an assistant that knows your athletes, from 19 EUR per month billed yearly, excl. VAT.

Update, 22 July 2026: Garmin has acquired TrainingPeaks and TrainHeroic (Garmin press release). Everything below describes the platform as it works today. For what the deal does and does not change, read Garmin acquires TrainingPeaks.

The Case for Intervals.icu

In our view, Intervals.icu is the free tool that made paid analytics justify themselves. David Tinker, a software developer and cyclist in Cape Town, started it in mid-2018 as a side project, originally as an analysis extension for Strava. He went full-time on it in September 2024, and a small team now builds it with him (About Intervals.icu). The platform counts 160,000+ active athletes and 193 million+ analyzed activities (Intervals.icu), and Supporter subscriptions help fund development and keep it independent (Intervals.icu pricing).

The Analytics Are Free

The core argument for Intervals.icu is blunt: the analysis features endurance athletes use most cost nothing. The free tier covers fitness, fatigue and form tracking with configurable CTL and ATL time constants (fitness chart), a multi-season power curve with several models (eFTP, Morton’s 3-parameter, Monod and Scherrer) (power curve), automatic interval detection with spike correction (activity timeline), decoupling analysis (decoupling) and a structured workout builder (workout builder). No credit card, no trial, no time limit (Intervals.icu pricing).

On TrainingPeaks, a Basic athlete account is free, and Premium adds the athlete’s own view of charts such as the Performance Management Chart and the Power Profile (TrainingPeaks charts). Intervals.icu’s own testimonials include an athlete who cancelled TrainingPeaks Premium and became a supporter instead (Intervals.icu). The optional Supporter tier costs 4 USD per month and adds, among other things, an annual training plan builder, full Strava history import, completely custom zones, advanced weather analysis, and teams and coaching organisations (Intervals.icu pricing).

Customization Without Limits

Beyond the standard charts, Intervals.icu lets you write JavaScript that runs on its servers to compute custom activity fields, interval fields and streams from FIT file data, and build custom charts with Plotly (custom JavaScript). The open REST API supports personal API keys, OAuth 2.0 and webhooks (open API), and Intervals.icu counts 250+ third-party app integrations (Intervals.icu). In our view, few platforms at any price give athletes and coaches who think in data this much freedom.

A Community That Ships

The Intervals.icu forum is the heart of its community: users suggest features, report bugs and help each other, and volunteers contribute translations (About Intervals.icu). The platform is available in 21 languages, and it connects to Garmin, Polar, Suunto, COROS, Wahoo, Strava, Zwift, MyWhoosh, Rouvy, Oura, WHOOP and Concept2, among others (Intervals.icu).

For the full picture, see our Intervals.icu Review.

The Case for TrainingPeaks

In our view, TrainingPeaks has long been a reference platform for structured endurance training, and its advantages are the kind that take years to build.

The Shared Language of Endurance Coaching

Dr. Andy Coggan and Hunter Allen pioneered TSS, with Banister’s heart-rate-based training impulse as the seed concept (what is TSS). Coggan also developed the Performance Manager, building on the impulse-response model Banister and colleagues first proposed in 1975, and TrainingPeaks put it into its Performance Management Chart with CTL, ATL and TSB (the science of the Performance Manager, PMC). Intervals.icu implements the same fitness, fatigue and form model (fitness chart), so this is common ground. In our view, when a coach and athlete discuss form before a race, they often still use the TrainingPeaks terms.

The Coach Network and Marketplace

This is where TrainingPeaks has the most reach. The Training Plan Marketplace sold 70,000+ plans in 2023 and gets 100,000+ visits per month (TrainingPeaks for coaches). Coach Match hand-matches athletes with accredited coaches, each certified by a national governing body and trained through TrainingPeaks University (Coach Match). The partner directory lists about thirty national governing bodies, including USA Cycling, British Cycling, Belgian Cycling and German Triathlon (TrainingPeaks partners). Intervals.icu has a coach directory too, with coaches listed by country (Intervals.icu coaches), but in our view it does not yet match this reach. For a coach building an international business, that reach is much of the product.

A Finished Mobile Experience

TrainingPeaks has iOS and Android apps with the calendar, messaging and zone settings (TrainingPeaks Messaging, zones on mobile), and its help center lists the few web features the app still lacks, such as the Structured Workout Builder (mobile app limits). Intervals.icu grew up as a web analysis tool (About Intervals.icu). In our view, TrainingPeaks offers the more polished mobile experience of the two, and for athletes who log, review and communicate from their phones, that difference shows up daily.

The Cost of the Standard

Price is the recurring objection. Premium for athletes costs 19.95 USD per month billed monthly, or 134.99 USD per year billed annually (TrainingPeaks for athletes), and TrainingPeaks adds tax on the invoice where it applies (sales tax). Coach Edition starts at 21.99 USD per month billed monthly with 4 Basic athlete accounts and 1 Premium athlete account, or 54.99 USD per month with 5 or more Basic athlete accounts, plus 9 USD per month for each Premium athlete the coach pays for, with volume discounts, excl. taxes. The page also lists a 99 USD start-up fee, which it waives with a coupon code shown on the same page (TrainingPeaks for coaches). The web app is available in English, French, German, Italian and Spanish, with more languages on mobile (TrainingPeaks languages). Our TrainingPeaks Review and TrainingPeaks Pricing cover the details.

Where Both Fall Short

In our view, different as they are, Intervals.icu and TrainingPeaks leave some of the same gaps, and they matter most to working coaches.

Lactate Testing

Both platforms work with thresholds. Intervals.icu estimates eFTP automatically from maximal efforts and lets you anchor custom zones to FTP, LTHR or your own fields (fitness chart, custom zones). Since February 2026 it also imports lactate data from Q-LAC devices into the activity timeline, with lactate interval fields (Intervals.icu forum). TrainingPeaks suggests threshold changes from your workouts and can apply them automatically, and it offers zone calculators based on thresholds (threshold notifications, zones calculator). What we did not find in either one’s documentation is a way to enter a lactate step test and derive LT1 and LT2 from it. On the Intervals.icu forum, a user who asked for lactate-based zones was pointed to entering a lactate threshold heart rate by hand and picking an LTHR-based zone preset (Intervals.icu forum). A coach who runs step tests then does that analysis in separate software and carries the zones over by hand, and every retest repeats that step.

A Built-in AI Assistant

We did not find a built-in AI assistant in either product’s documentation (Intervals.icu features, TrainingPeaks help center). Intervals.icu’s app integrations include AI coaches built by third parties on its open API (app integrations), and its users have asked for an official MCP server so they can connect ChatGPT or Claude without community tools (Intervals.icu forum). The TrainingPeaks API is open to approved developers only, not for personal use (TrainingPeaks API).

Intervals.icu as a Coaching Business Platform

Coaches work in Intervals.icu: anyone can follow or coach other athletes, with tagging, a compliance overview and group chat (athletes, chat), and Supporter adds teams and coaching organisations (Intervals.icu pricing). On its feature pages we did not find tools for billing or invoicing clients, or branded client reports (Intervals.icu). In our view, the interface’s depth is also a learning curve for non-technical athletes.

TrainingPeaks and Communication

TrainingPeaks has post-activity comments, and TrainingPeaks Messaging adds direct and group conversations between coaches and Premium athletes in the web and mobile apps (TrainingPeaks Messaging). Messaging is limited to Premium athletes and coaches aged 18 and older, so athletes on a free Basic account rely on post-activity comments or another channel. Coach costs also rise with each Premium athlete the coach pays for, with volume discounts from 10 athletes up (TrainingPeaks for coaches).

The Multi-Tool Stack

A coach who wants deep analytics, professional delivery, communication and lactate testing often ends up running two platforms plus testing software. In our view, each seam between tools costs money, time and data integrity.

The Case for Coachbox

We build Coachbox, so read this section knowing where it comes from. Coachbox is built for professional endurance coaching grounded in lactate testing.

Testing Inside the Coaching Loop

Run a lactate test and enter the values, or upload a photo of the paper protocol. Coachbox detects LT1 and LT2 automatically in under a minute, and the resulting zones apply to the athlete’s future sessions. Zones are dated, so older workouts keep their analysis against the zones that were valid on that day. A branded PDF report of the test is ready for the athlete. Every coaching plan includes a set of free tests at the start of the licence, with per-test pricing after that. When a test takes minutes instead of an evening, testing becomes a regular service instead of an occasional project.

AI That Knows Your Athletes

Coachbox AI answers questions about a specific athlete, a workout, a lactate test or a whole season, and writes changes straight into the athlete’s training plan. Coachbox also connects to ChatGPT, Claude and other assistants over MCP.

A Complete Coaching Platform

Around the testing core, Coachbox covers the coaching workflow: a training calendar with annual planning, structured workouts that go out to the athlete’s Garmin, Wahoo or COROS device, training load with the Coachbox Stress Score, in-app messaging and comments on individual workouts, HRV, sleep and resting heart rate from the athlete’s device, the Coachbox Academy for coach education, and a way for athletes to find a coach on the platform.

European and Transparent

Coachbox prices in EUR: from 19 EUR per month billed yearly (25 EUR billed monthly) for Base up to 149 EUR per month billed yearly (190 EUR billed monthly) for Prime, excl. VAT, with 5 to 100 athletes included. Athletes of a coach use the app for free, and there is a 14-day trial without a credit card. Coachbox counts 25,000+ users and 12 million+ logged workouts across 35+ countries.

For the direct comparisons, see Coachbox vs Intervals.icu and Coachbox vs TrainingPeaks.

Three-Way Comparison Table

Coach rows compare prices without VAT, athlete rows prices with VAT. TrainingPeaks lists its coach prices in USD with “additional taxes may apply”, so they are shown excl. taxes. Athlete prices with VAT are not available for either vendor. TrainingPeaks lists its athlete prices before tax and adds tax on the invoice as a separate line: VAT of 18% to 27% in Europe depending on the buyer’s country, and sales tax in some US states (sales tax). Its home country, the US, has no VAT rate to convert with. Intervals.icu does not state a tax basis for the Supporter tier. We therefore show both vendors’ prices exactly as listed and do not convert them. Coachbox lists its prices in EUR without VAT; the athlete row shows Coachbox One with the 19% German VAT and without VAT, so you can compare on either basis. We do not convert between currencies.

The three products bill different things. Intervals.icu charges nothing for coaching (Intervals.icu pricing). TrainingPeaks bills a coach account plus each Premium athlete the coach pays for (TrainingPeaks for coaches), and Coachbox bills a plan with a number of athletes included plus a fee per extra active athlete. What a roster costs therefore depends on its size and on how many athletes need Premium, so we do not add these up into one yearly total.

Real Coaching Scenarios

Scenario 1: Self-Coached Cyclist Who Loves Data

You train yourself, own a power meter, and spend rest days reading your own charts. You have no coach and no plans to hire one.

Best choice, in our view: Intervals.icu. It was built by a cyclist who wanted better analysis for his own training (About Intervals.icu). Free, deep and customizable. Becoming a supporter at 4 USD per month is a fair thank-you.

Scenario 2: Athlete Working with a TrainingPeaks Coach

Your coach delivers plans through TrainingPeaks, reviews your files there, and your federation program works with it.

Best choice: TrainingPeaks. The platform your coach works in is the right platform. Intervals.icu can import your history from TrainingPeaks (fitness chart), so a free account alongside for personal analysis costs nothing.

Scenario 3: Coach Who Tests Athletes

You coach 15 to 40 endurance athletes, run lactate step tests every 8 to 12 weeks, and currently juggle a delivery platform, a testing spreadsheet and hand-built PDF reports.

Best choice, in our view: Coachbox. Test results turn into zones for the coming sessions, LT1 and LT2 detection is automatic, and branded reports replace the handmade ones. In the documentation of Intervals.icu and TrainingPeaks, we did not find lactate step-test analysis.

Scenario 4: European Coach Adding Testing as a Service

You coach in the Benelux, price your services in euros, and want to add lactate testing as a paid service.

Best choice, in our view: Coachbox. EUR pricing keeps the books simple, and integrated testing makes the new service practical. Keep a free Intervals.icu account for your own training if you like; the two coexist.

Who Should Choose What

Choose Intervals.icu if you are…

• A self-coached athlete who wants deep analytics in a free tier
• A data enthusiast who builds custom charts and metrics in JavaScript
• A coach of technical athletes happy with a shared data workbench and a 4 USD Supporter tier
• Budget-driven above all: the core platform costs nothing

Your stack: Intervals.icu for everything analytical. Add separate tools if billing, lactate testing or client reporting enter your practice.

Choose TrainingPeaks if you are…

• An athlete whose coach or federation works in TrainingPeaks
• A coach building revenue through the Training Plan Marketplace and Coach Match
• Committed to the TSS/CTL/ATL vocabulary as your shared language
• Looking for a mobile app that most coached athletes already know, in our experience

Your stack: TrainingPeaks for delivery and messaging with Premium athletes, and separate testing software if you run lactate tests.

Choose Coachbox if you are…

• A professional endurance coach, especially one who runs lactate tests or wants to start
• Tired of carrying zones by hand from testing software to a delivery platform
• Interested in an AI assistant that answers from your athletes’ data and edits their plan
• Consolidating testing and coaching into one EUR subscription

Your stack: Coachbox for testing, planning, communication and test reports in one place.

The Bigger Picture

Intervals.icu versus TrainingPeaks is really a question about who does the coaching. If you coach yourself, in our view Intervals.icu wins this matchup: the analytics are free and deep, and development moves fast. If someone else coaches you, or you coach others inside the TrainingPeaks ecosystem, its reach counts, and the subscription is part of the cost of that reach.

The question we did not see either platform answer in its documentation is lactate step testing. Both work with thresholds from field data or values you enter, and the lab or step-test analysis happens elsewhere. That is the gap Coachbox aims at: a lactate test becomes zones, an updated plan and a client-ready report in the same platform.

Pick by where your training truly lives: in your own charts, in the TrainingPeaks ecosystem, or in a testing-driven coaching practice that runs on one platform instead of three.