Quick comparison
| Feature | Baseline | Intervals.icu | |---|---|---| | Pricing | $0 / $12/month / $249 lifetime | Free with optional $1.50/mo supporter | | Free tier | Yes (limited) | Yes (nearly everything) | | Multi-sport | First-class (run, ride, swim, hike, tri, ski) | Cycling-first, running second | | Cross-source | WHOOP + Garmin + Apple + Coros + Oura (live & planned) | Strava + Garmin + WHOOP + Oura | | AI insights | Daily "three things to know" card + weekly summary | None | | Heatmap | Full-resolution V3.1 with bleed and interactivity | Available (simpler rendering, less geographic depth) | | Geographic depth | Country/state stats, trip detection, altitude tracking | Limited to basic activity maps | | Mobile experience | Designed-down responsive web | Functional but not optimised for mobile | | Achievement system | 50+ badges with public profiles, distance milestones | None | | Workout planning | Planned (Pro+ tier, not yet available) | Built-in workout designer and structured plan support | | Data export | Full JSON download in one click | Activity-level export | | Solo developer | Yes (Liam, Melbourne, Australia) | Yes (David Tinker, UK) | | Development maturity | ~1 year (public beta early 2026) | 6+ years of continuous refinement | | Sport type coverage | Run, ride, swim, hike, triathlon, multi-sport, ski | Cycling primary, running secondary, swim basic |
Where Intervals.icu wins
Intervals.icu is one of the most genuinely impressive free tools on the internet. David Tinker has built something remarkable over 6+ years of solo development:
It's free. The supporter tier ($1.50/month) is symbolic - nearly all features work without payment. For athletes on a budget, Intervals.icu delivers extraordinary value. Baseline's free tier is more limited, and Pro costs $12/month.
Cycling depth is exceptional. If you're a cyclist who wants training load tracking, power curve analysis at every duration, fitness trend charts, and structured workout planning in one place, Intervals.icu delivers at a level Baseline doesn't yet match. The power analysis tools - critical power chart, power duration curve, quadrant analysis - are comprehensive and refined over years.
Mature edge cases. Six years of refinement means unusual sport types, rare file formats, and odd edge cases are handled well. If your training setup involves niche devices or unusual data sources, Intervals.icu is more likely to handle it gracefully.
Built-in workout designer. Intervals.icu includes a structured workout builder where you can design intervals, prescribe power targets, and schedule them on a calendar. This is a feature Baseline has planned for the Pro+ tier but doesn't yet have. For cyclists who follow structured indoor training, this is a significant capability.
Open data philosophy. Intervals.icu makes it easy to get your data in and out. The platform doesn't try to lock you in. The free pricing model reinforces this - the product is genuinely useful without payment, and the supporter tier is a voluntary contribution.
Community and documentation. David maintains excellent documentation, release notes, and a user forum. The platform is transparent about its capabilities and limitations. There's no marketing opacity - you know exactly what you're getting.
Where Baseline wins
Baseline is built for a different athlete. The strengths reflect different priorities:
Cross-source data integration is unique. Intervals.icu connects to Strava, Garmin, WHOOP, and Oura - but it treats them as separate data sources. Baseline treats all your connected devices as a single dataset. Your WHOOP recovery score appears next to your Strava training load next to your Garmin Body Battery. The correlations between recovery and performance are surfaced automatically. Intervals.icu cannot do this because it doesn't cross-reference data across sources.
Multi-sport is first-class, not an afterthought. Intervals.icu is cycling-first with running second. Baseline treats running, cycling, swimming, hiking, triathlon, and multi-sport as equal citizens. The training load model normalises TSS across sports - your swim TSS combines with your run TSS into a single CTL/ATL/TSB chart. If you do more than one sport, Baseline's unified model is more accurate.
Visual design matters for daily engagement. Intervals.icu is functional and data-dense. It shows you everything and expects you to find what matters. Baseline is curated - the dashboard surface the most important metrics first, with progressive disclosure for depth. The visual hierarchy makes daily check-ins faster and more pleasant. For athletes who actually want to look at their data every day, good design is a retention feature.
AI insights without a chatbot. Baseline's daily "three things to know" card reads your data and surfaces what changed. No prompts, no conversations, no setup. It just tells you what's different about today compared to last week. Intervals.icu has no AI features at all. For athletes who want their data interpreted, not just displayed, this matters.
Geographic depth. The full-resolution heatmap with bleed rendering, country-by-country stats, trip detection, and altitude tracking - these are features for athletes who care about where they train. Intervals.icu's maps are simpler and lack geographic analysis.
Pricing flexibility for long-term users. Baseline's $249 lifetime option means you pay once and own the platform. At $12/month for Pro, break-even is 21 months. For athletes who plan to use the platform for years, lifetime pricing is cheaper than free - if you value your time, the quality difference justifies the cost.
Achievement system. 50+ badges for distance milestones, elevation goals, consistency streaks, and sport diversity. Public profiles with badge displays. This is a gamification layer that Intervals.icu doesn't have. For some athletes it's a motivator; for others it's irrelevant. But it's a genuine differentiator.
Feature comparison deep dive
Training load models compared. Both platforms use CTL/ATL/TSB, but the implementation differs. Intervals.icu uses fixed time constants (42/7 days) and calculates TSS primarily from power data for cycling and heart rate for other sports. Baseline allows configurable time constants and uses sport-specific TSS formulas - rTSS for running (based on pace and heart rate), TSS for cycling (based on power or heart rate), and swim TSS (based on pace). For multi-sport athletes, Baseline's sport-specific normalisation produces more accurate combined load numbers.
Cross-source data integration. Intervals.icu connects to multiple platforms but displays them as separate data silos - you can see your WHOOP recovery on a separate tab, but it's not correlated with your training load on the main dashboard. Baseline treats all sources as a single dataset. Your WHOOP recovery score appears next to your training load chart. Your Oura sleep stages are correlated with your next day's performance. This cross-source correlation is the defining architectural difference between the two platforms.
Power analysis depth. For pure cycling power analysis, Intervals.icu is more mature. The power duration curve, quadrant analysis, power distribution histograms, and fitness trend charts have been refined over 6+ years. Baseline's power analysis covers the essentials (FTP, NP, IF, TSS, critical power curve) but lacks the depth that dedicated cyclists expect. If power curve analysis is your primary use case, Intervals.icu is stronger today.
Visual design philosophy. Intervals.icu displays every available data point and trusts you to find what matters. Baseline curates - it surfaces the most important metrics first and provides progressive disclosure for depth. For athletes who want to see everything at once, Intervals.icu's approach is better. For athletes who want a daily check-in that highlights what changed, Baseline's approach is better.
Multi-sport normalisation. This is the strongest argument for Baseline. Intervals.icu is cycling-first with running as a secondary sport. Swimming support exists but is basic - no SWOLF tracking, no open-water pace normalisation. Baseline treats all sports equally, with sport-specific metrics (CSS for swimming, GAP for running, VAM for cycling, elevation analysis for hiking) and a unified training load model that combines TSS across all sports into a single CTL/ATL/TSB chart.
AI and insights. Intervals.icu has no AI features. Your analysis is manual - you look at the charts and draw conclusions. Baseline's daily "three things to know" card automatically surfaces changes in your training patterns. If you know how to interpret training data, Intervals.icu gives you all the raw material. If you want a system that flags what's worth paying attention to, Baseline saves you time.
Pricing comparison
Intervals.icu is free - or effectively free, with a $1.50/month supporter tier that is entirely optional. Baseline's free tier is functional but limited. Baseline Pro at $12/month offers more features (AI insights, cross-source correlation, geographic depth, achievement system) but costs money. The $249 lifetime option makes Baseline a one-time purchase for long-term users. The honest assessment: if price is your primary constraint, Intervals.icu wins. If you value the additional features Baseline offers, the cost is modest relative to the value of understanding your training data.
Where they're even
Both platforms handle the basics well: activity display, GPS maps, basic metrics (pace, power, heart rate, elevation), and data import from Strava. Both are built by solo developers who are responsive to user feedback. Both are focused on analysis rather than social features. Both are web-first with responsive design. Both have free tiers. Both will likely exist in five years - these are not fly-by-night projects.
The honest recommendation
If your decision criterion is "which tool gives me the most for free?": Intervals.icu. Easy choice. David Tinker's work is exceptional, and the free tier is nearly unlimited. For cyclists on a budget, there is no better option.
If your decision criterion is "which tool shows me my training across all my devices in the most useful and beautiful way?": Baseline. The cross-source dashboard, visual design, AI insights, and geographic depth are genuinely different from what Intervals.icu offers. The free tier lets you test this without commitment.
If you're a pure cyclist: Try Intervals.icu first. You'll likely find everything you need at zero cost. If you find yourself wanting cross-source recovery data, better design, or geographic analysis, Baseline adds value on top.
If you're a multi-sport athlete: Baseline is the better fit. The unified training load across sports and the cross-source dashboard solve problems that Intervals.icu doesn't address.
The optimal setup: Use both. They're cheap or free. Connect your data to both platforms. Use Intervals.icu for cycling power analysis and workout planning. Use Baseline for cross-source insights, geographic analysis, and daily check-ins. There's no lock-in - both tools make it easy to connect and disconnect.
Try Baseline free → or try the demo → - and also check out Intervals.icu. They're both worth your time.