I should say upfront: I'm the person building Baseline. So this comparison comes with an obvious bias and you should read it with that in mind. I've also used Intervals.icu for years before starting Baseline, and I think David Tinker (Intervals.icu's solo developer) has built one of the most genuinely useful free tools on the modern internet.
This post is the honest version of "should you use Baseline or Intervals.icu." If you read it and decide Intervals.icu is the better fit for you, that's a perfectly fine outcome.
What Intervals.icu is
Intervals.icu is a free, web-based training analytics platform built by a single developer (David Tinker) over the last six years. It pulls data from Strava, Garmin Connect, WHOOP, Oura, Wahoo, and a handful of other sources, and gives you:
- Training load tracking (CTL, ATL, TSB / Form)
- Activity-level analysis
- Power curve and pace curve charts
- Custom workout planning
- Heatmap of training locations
- Wellness tracking (HRV, sleep, RHR, weight)
- Goals, race events, training plans
- A loyal forum community
It's free with an optional supporter tier ($1.50/month) for a few extra features. The supporter model funds the project.
It's mature, deep, and built by someone who understands the domain extremely well. It's also the most-recommended training analytics tool on r/Velo, r/AdvancedRunning, and Slowtwitch for a reason.
What Baseline is
Baseline is a newer (launching mid-2026), paid platform focused on dashboard-quality presentation, multi-source insight overlays, and a beautiful default view of your training and body data.
The core differences in product philosophy:
- Visual quality is a first-class concern. The dashboard is designed, not just functional.
- Multi-source by default. Cross-source insights (e.g., WHOOP recovery × performance, sleep × training quality) are foregrounded, not buried.
- AI insights overlay the dashboard. Daily summaries, weekly narratives, and "Ask Baseline" chat - but pull-style, never push.
- Outdoor and multi-sport athletes are the primary persona. Hiking, ultrarunning, multi-sport, geographic features get equal weight to traditional cycling/running analytics.
Pricing: $0 free tier, $12/month Pro, $108/year annual, $249 one-time lifetime founder access (limited).
Where Intervals.icu wins
1. Free is hard to beat
For an athlete who wants comprehensive training analysis without paying for a subscription, Intervals.icu is unrivalled. You get full CTL/ATL/TSB tracking, power curves, training plans, and wellness charts for $0 (or $1.50 if you want to support the project).
2. Training load and structured workout focus
Intervals.icu has six years of refinement around training-load tracking, FTP/threshold zone management, and structured workout planning. The Calendar view, the workout builder, and the integration with TrainingPeaks-style structured training plans are mature and widely used by coaches.
3. Workout file editing and analysis
You can manually edit activities, fix bad GPS, recalculate metrics. This is genuinely useful for serious athletes whose data quality matters.
4. Deep cycling-specific analysis
For cyclists who want to deep-dive into individual ride power data - interval detection, peak power analysis, normalized power calculations, custom intervals - Intervals.icu is extremely well-developed.
5. Community and longevity
Six-year-old project, loyal forum community, frequent updates from David. It's not going anywhere. New tools come and go; Intervals.icu has earned its place.
6. The supporter pricing
$1.50/month for the supporter tier is generous. If you want to support a free tool you use, that's a fair ask.
Where Baseline wins (or aims to)
1. Visual design and dashboard polish
This is the most honest and important difference. Intervals.icu is functional but visually dense. The default views haven't changed much in years. Charts are utilitarian.
Baseline is built with the assumption that an athlete dashboard should look as good as the product on your wrist. Typography, spacing, colour, density, and theme are all tuned. If you find Intervals.icu visually intimidating, Baseline is a clean alternative.
2. Multi-source cross-analysis
Intervals.icu shows you WHOOP and Oura wellness data, but the cross-analysis (e.g., "your power output drops by 12% on days following <80% recovery") isn't really there. It's a feature surface that's been on the roadmap for a while.
Baseline foregrounds these. The Cross-source screen shows correlations between recovery metrics and performance, sleep duration and training quality, HRV trends and acute training load. This is genuinely the analysis I (the founder) wanted that nothing else surfaced.
3. Outdoor / hiking / multi-sport equal treatment
Intervals.icu is built for cyclists primarily, with running as a respected second-class citizen. Hiking, ultrarunning, multi-day adventures, and "I trained on a glacier in Patagonia" data are not first-class.
Baseline is built around a multi-sport athlete who hikes, runs, rides, swims, and travels. Geographic features (full heatmap, country/state coverage, trip detection, altitude/depth tracking) are not afterthoughts.
4. AI insights without a chatbot
Baseline includes a daily insights card on the Overview ("three things to know today" - written by AI, not pushed at you), weekly summary emails, and an "Ask Baseline" chat that lets you ask questions of your own data. Intervals.icu has none of this.
If you want AI in your training analytics but you don't want a chatbot DMing you on WhatsApp, Baseline's "ask, don't push" approach is the middle ground.
5. Mobile experience
Intervals.icu's mobile web is functional but not great. Baseline's mobile dashboard is a first-class experience (designed-down from desktop, not bolted-on later), with native apps planned post-launch.
6. Achievements and public profiles
Baseline has 50+ achievement badges (volume, performance, geographic, consistency, easter-eggs) and shareable public profile pages. Intervals.icu has none of this.
If you'd never share your training data online, fine - these don't matter to you. If you'd post your year-end heatmap on Strava, they do.
Where they're roughly even
- Strava integration: both are reliable.
- Wellness data import: both pull WHOOP, Oura, sleep.
- Training load math: both compute CTL/ATL/TSB correctly. The science is solved.
- Power curve / pace curve: both produce these well.
- Privacy: both keep your data private; neither sells it.
A blunt question: is Baseline worth $12/month over Intervals.icu's $0?
Honest answer: for many athletes, no. If you're a cyclist who wants comprehensive training-load tracking and you're happy with Intervals.icu's interface, paying $12/month for a prettier version of similar features is bad value.
Where Baseline becomes worth it:
- You wear multiple devices (e.g., WHOOP + Garmin + Apple Watch) and you want them analysed together, not just imported.
- You're a multi-sport / outdoor athlete and you want geographic features (full heatmap, trip detection, country tracking) treated as core.
- You value visual design enough that "the dashboard looks good" actually changes whether you check it.
- You want AI insights/summaries but not a chatbot interface.
- You want shareable badges and public profiles.
If none of those describe you, stick with Intervals.icu. It's a brilliant tool.
A note on "supporting indie devs"
Both Baseline and Intervals.icu are built by solo developers (David Tinker for Intervals; me for Baseline). Both are responsive to user feedback. Both will likely still exist in five years.
If your decision criterion is "support an indie developer," $1.50/month to David supports him. $12/month to Baseline supports me. Either is reasonable. The tools serve overlapping but different audiences.
The recommendation
- Cyclist focused on training-load and structured workouts, happy with utilitarian design, doesn't want to pay: Intervals.icu. Easy choice.
- Multi-sport athlete, multiple wearables, values design and cross-source insights, willing to pay: Baseline.
- Trying to decide: use Intervals.icu free for a month, then try Baseline's free tier or 14-day Pro trial. Don't take my word for it.
Both tools exist because the existing fitness platforms (Strava, Garmin Connect, WHOOP) treat analysis as an afterthought. The fact that two indie developers can build comprehensive alternatives says something about the gap. Pick the one that fits how you think about your data.