Start Here: It Is Free, And It Is Very Good

Most comparison pages open by explaining why the other product falls short. This one cannot, and should not.

Its own description is the most useful thing on this page: “a free training platform built by athletes, for athletes”, offering powerful analytics and a community. Built by athletes for athletes explains both halves of the experience — why it is so capable, and why so little of it is smoothed off for you.

intervals.icu began in 2018 as a Strava analysis extension built by David Tinker, a developer and cyclist in Cape Town. It is now used by more than 160,000 athletes who have run over 193 million activities through it. For an individual athlete it is free, and generously so. Fitness, fatigue and form tracking, activity analysis, interval detection, the training calendar, the workout builder, the power curve, multisport, device integrations and custom charts all cost nothing, permanently. The Supporter tier is four dollars a month, and it is where teams, coaching organisations, bulk athlete configuration, fully custom zones and full Strava history import live. Four dollars is not a barrier to anybody, but it is worth being precise: coaching at scale on intervals.icu is a paid feature, not a free one.

It is also genuinely well built. The performance management chart, the power curve, the decoupling analysis, the custom charts: these are not a cut-down version of a paid tool. For a self-coached athlete who enjoys sitting with their own data, it is one of the best things in endurance sport, and no honest comparison would suggest otherwise.

So the question is not whether intervals.icu is good. It is what you are trying to do.

Both Platforms Model Critical Power

This is worth stating plainly, because it is where most comparisons of this kind get lazy.

Vekta is built on Critical Power and W′ rather than FTP, and that distinction does real work against platforms anchored to a single threshold number. It does not do that work here. intervals.icu models critical power too, on the power curve, using eFTP alongside Morton’s three-parameter model and Monod & Scherrer. A coach who knows what those are will not be told anything new by a page claiming Vekta introduced critical power to the category. It is not alone in that either — Xert arrives at the same physiology by a different route.

The difference is not the presence of the model. It is what the platform does with it once it exists.

In Vekta, Critical Power, W′, D′ and Pmax are not outputs on an analysis screen. They are shared state. Zone generation reads them. Interval classification reads them. Durability reads them. The carbohydrate recommendation reads them. When the model updates, every one of those updates with it, on its own, that day. In intervals.icu the model is something you consult. In Vekta it is something the platform acts on.

One Model, Or Three

There is a difference underneath the two platforms that does not show up in a feature list, and it is the one that matters most over time.

Open the power curve in intervals.icu and you are offered a choice of models. eFTP, Morton’s three-parameter, Monod & Scherrer. You pick the one you trust, and you read it. That is a genuine strength, and for an analyst who knows the differences between those models it is exactly right.

Vekta has one. Critical Power, W′, D′ and Pmax are not an analysis screen you visit, they are shared state that the rest of the platform reads and writes back to. Zone generation reads it. Interval classification reads it. Durability reads it. The carbohydrate target reads it. When the model moves, all of them move, that day, without anybody asking.

The practical test of this is what happens when the platform learns something new.

When Vekta extended its model to running in July 2026, it did not ship a running feature. Critical Power and critical speed began computing automatically, and D′, W′, zone generation, peak profiles and the Performance view in Insights arrived with them. None of those were built individually. They were already there, waiting for the model to reach the sport.

A platform of independent parts has to be extended part by part every time the science moves. A platform with one model absorbs it. Choosing software today is not really a choice about what is on the screen this morning — it is a choice about what it will be capable of in three years.

Detection, And Then Classification

Both platforms find the efforts in a ride automatically. That is where the similarity ends.

intervals.icu detects efforts using spike detection and correction across power and heart rate, and presents them for you to read. It is quick and it is reliable, and for an athlete reviewing their own ride it is usually all that is needed.

Vekta reads duration, power relative to that athlete’s Critical Power, cadence and torque simultaneously, then classifies what it found. Every effort is labelled by intensity type against the athlete’s own physiology: Neuromuscular above 180 percent of CP, Anaerobic between 130 and 180 percent, VO2max between 105 and 130 percent, and so on down. The session as a whole is then assigned a training stimulus, and if the structure indicates a race, Vekta says so and classifies the type.

The distinction is between a list of efforts and an interpretation of what the session did to the athlete.

For one rider reviewing one ride, a list is fine. Across a roster of thirty, on a Monday morning, the difference between a list and an interpretation is most of the working day.

The Learning Curve Is The Real Cost

This is the part of the decision that is easiest to underestimate, and for most coaches it matters more than any single feature.

intervals.icu is deep, and its depth is available to you through configuration. Custom charts, custom fields, an open API. If you know what you want to look at, you can build it, and almost nothing is off limits. That is a real strength and it is why the people who love it, love it.

It is also the cost. The configuration is the work, and the work sits with you. Its own forum carries threads titled Where to start how to learn Intervals.icu and Guide needed for Newbie. Long-standing users describe the interface as overwhelming to begin with and talk about a real learning curve. These are not detractors. They are the community, being honest, and they usually finish the thought the same way: it is worth the time you put in.

The fairest summary anyone has written about it came from one of its own supporters: for self-coached, data-savvy athletes, it is close to perfect.

Read that sentence twice, because it is a compliment and a specification at the same time. Self-coached. Data-savvy. That is who the platform is built for, and it serves them better than anything else at any price.

The question is whether it describes you. A coach with thirty athletes and a Monday morning does not have an afternoon to spend building a chart, and will not have one next month either. An athlete who wants to train rather than analyse is not the target user and will feel it. Neither is a criticism of intervals.icu. It is a statement about fit.

Vekta makes the opposite trade deliberately. It is opinionated. It decides what to put in front of you and does not offer to let you rebuild it. You lose the ceiling that customisation gives you, and you gain being useful on the first morning without a project to get there.

The Analysis Arrives Done

This is the central difference between the two platforms, and it is a difference of philosophy rather than feature count.

intervals.icu gives you an extremely capable set of tools and trusts you to use them. Custom charts, custom fields, and a view built exactly the way you want it. If you know what you want to look at, you can build it, and the ceiling is very high.

Vekta decides what matters and puts it in front of you. Every session generates a written summary, delivered automatically to both coach and athlete. Session comparison surfaces the most similar past efforts on its own, rather than waiting for you to remember which ride to compare against. Durability reports peak power at fixed fatigue levels, from 0 to 50 kJ/kg, in every session without being asked. W′ Balance tracks depletion second by second and previews it on a prescribed workout before the athlete rides it.

Neither approach is correct in the abstract. A tool that waits to be asked rewards curiosity and time. A tool that arrives with an answer rewards neither, and gives you back the hours instead. Which is better depends entirely on which of those you have more of.

Fuelling

Vekta calculates a carbohydrate target for every session it generates, in grams per hour, and puts it on the workout and the calendar card before the athlete starts.

The number is not from a table. It is calculated from Vekta Volume, the total work demand normalised for body weight, and Vekta Intensity, how hard that work is for that specific athlete relative to their Critical Power, W′ and Pmax. Two athletes given the identical session receive different numbers, because the identical session is not identical work for both of them. Recommendations run from around 10 to 20 g/h for easy and recovery sessions up to a ceiling of 120 g/h, and they move as fitness moves, with no separate test.

intervals.icu has no equivalent. This is not a criticism of an analysis platform for not being a nutrition platform. It is simply a capability that exists on one side and not the other.

Mobile

intervals.icu is web-first, and the desktop browser is where it is strongest. There is no first-party mobile app. There are good third-party companion apps built on its public API, and for many athletes that is enough to check a chart on the way to work.

Vekta’s mobile app is not a viewer. Workouts can be created and edited on it, including by voice on supported devices. Activities can be edited, streams reviewed, sessions analysed. Coaches can open the app, move between athletes and see the same data they see on desktop. Notifications arrive for new activities and comments.

For an athlete this is the difference between reviewing training and doing it. For a coach it is the difference between being at a desk and not.

Coach Tools

intervals.icu supports coaches. Athletes can be followed, tagged and organised, there is chat, and there is an Ask A Coach feature. For a coach with a handful of athletes who is comfortable in the tool, it works.

Vekta is built the other way round, starting from the roster. The coach dashboard shows every athlete at once with load, recovery, sleep, HRV, resting heart rate, wellness score and the coming days, so a gap in anyone’s calendar is visible without opening their calendar. Sessions copy and paste between athletes. A library workout can be assigned to several athletes in one action. Chat sits inside the session analysis itself, so the conversation happens next to the data it is about, rather than somewhere else.

One is a platform that accommodates coaching. The other is a platform designed around it.

Integrations, And The Strava Question

intervals.icu connects to more than 250 platforms, including Strava, and full Strava history import is one of the Supporter features. Given that the project began as a Strava analysis extension, that lineage runs deep, and for a large number of athletes Strava is where their training life already lives.

Vekta connects directly to device platforms instead: Garmin, Wahoo, Hammerhead, COROS, Zwift and Stryd for training data, and WHOOP, Oura, Tymewear and CORE Body Temperature for recovery and health. Vekta does not integrate with Strava, and this is a deliberate decision rather than an omission. Aggregators process and smooth FIT file data before passing it on. Vekta pulls raw data from the source to preserve the precision of power, cadence and torque that the model depends on.

That is a real trade-off and it should be read as one. If Strava is central to how you work, intervals.icu accommodates that and Vekta does not. intervals.icu also has a public API, with a real ecosystem of third-party apps built on it. Vekta’s own public API is scheduled for release in October 2026, which as of writing has not happened yet.

For Athletes

If you are self-coached, comfortable with your own data, and you enjoy the analysis, intervals.icu is very hard to argue against. It is free, it is powerful, it connects to almost everything, and there is a community around it that will answer your questions. Adding a subscription to that is a decision that needs justifying, and for a lot of athletes it will not be justified.

Vekta makes sense for an athlete when one of three things is true. You work with a coach, and want the two of you inside the same platform with the analysis and the conversation in one place. You want the interpretation rather than the tools, arriving after every session without being asked. Or you want the things that follow from a model the platform acts on: zones that update daily without a test, a fuelling target on every session, W′ Balance previewed before you ride, durability measured in every session rather than tested for.

An athlete seat is €19.99 a month or €179.99 a year, with a 14-day free trial. If none of those three things is true for you, intervals.icu is the better answer and we would rather say so.

For Coaches

The calculation is different, because the constraint is different.

A coach’s bottleneck is rarely the depth of analysis available on any one file. It is the number of files, the number of athletes, and the number of hours. Thirty athletes uploading four or five sessions a week is well over a hundred files, every week, each of which has to be looked at, understood and acted on.

A Vekta coach account is free, permanently, whatever the size of the roster. On intervals.icu, teams and coaching organisations sit on the Supporter tier at four dollars a month, which is not a meaningful cost to anyone, but is worth knowing is not the free tier. You pay for athlete seats, and you decide athlete by athlete whether you cover the seat or they do. That is the whole pricing model. It exists because the platform’s argument is about the coach’s time, and charging for the coach’s seat would sit oddly next to that.

Running, Swimming And The Shape Of Multi-Sport

Both platforms handle more than cycling. The difference is whether the other sports inherit the model or approximate it.

intervals.icu supports cycling, running, triathlon and other endurance sports, with the same charts and the same performance management approach applied across them.

Vekta extended its model to running in July 2026, and the way that happened is the point. Critical Power and critical speed began computing automatically for running, and D′, W′, zone generation, peak profiles and the Performance view in Insights all arrived at the same moment. None of them were built individually. They were already there, waiting for the model to reach the sport. Swimming zones generate from critical pace and maximum heart rate, pool lengths are parsed as intervals, and triathlon activities split into per-discipline sub-activities automatically.

For a coach working across disciplines, that means running is not a lesser version of the cycling product. The metrics, the zones and the analysis are correct for the sport rather than adapted from another one.

If You Decide To Move

There is not much to it, and no export step.

Athletes connect their device accounts directly to Vekta, and history imports on its own, with the performance context intact. Because Vekta reads from the device source rather than from an aggregator, what arrives is the raw file rather than a processed copy. Zones, Critical Power and W′ are then computed from that history rather than carried over as settings, so there is nothing to reconfigure and no test to sit before the platform is useful.

A coach account is free, so the roster can be set up and populated before anyone decides anything. The 14-day trial covers every athlete on it.

Who Should Stay On intervals.icu

Anyone whose bottleneck is not time. If you enjoy building the analysis, if you want charts nobody else has, if you have a workflow that depends on Strava, or if you want an open API to build against, intervals.icu does things Vekta does not and does them well.

It is also the right answer for anyone who simply does not want another subscription. Free is a genuine feature, and it is the one thing on this page that Vekta cannot match.

Where Vekta earns the difference is when the analysis needs to arrive rather than be assembled, when it needs to arrive on a phone as readily as a desktop, and when it needs to do that for a roster rather than a rider.

Still Weighing It Up?

This page compares two platforms. If you are earlier than that and still drawing up a shortlist, we have reviewed every credible intervals.icu alternative — including the ones that beat us — with 2026 pricing for each: intervals.icu alternatives.