Comparison

Fartlek vs OnTrack Interval Timer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Fartlek

Features
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Tell your AI coach your goal and the days you can run, and get a training plan that adapts every week to how your runs go. Need a single workout? Describe it or paste a screenshot, and it's ready in seconds. Then just run: voice and haptic cues guide every interval, even with your screen off. 25 workouts runners actually love — HIIT, fartlek, tempo, hills, Yasso 800s. On iPhone and Apple Watch. Because running the same pace every day only makes you better at running the same pace. Break the plateau. EVERY RUN IS A NEW CHALLENGE Every workout here has a specific goal and a different feel — so you actually train different muscles, systems, and skills instead of just logging miles. Your running workout is fun now :) Speed: 200m pops, ladders, strides, sprint finishers Strength: Hill repeats, power builders, switchbacks Stamina: HIIT, Cruise intervals, tempo waves, Yasso 800s Endurance: Progressive aerobic, negative splits, scenic cruises Fun: Fartlek games, stoplight play, music flow runs Each workout has a warm-up, main set, and cooldown — with clear effort guidance through every phase. AI WORKOUT GENERATOR Tell the AI coach what you want — "30 minutes, hill repeats, moderate" or "a fartlek that doesn't bore me" — and get a runnable workout in seconds. Paste a screenshot of a workout you saw online and we'll convert it into intervals. TRAIN BY EFFORT, NOT NUMBERS Every interval shows a target effort (80% for work, 30% for recovery). No heart rate monitor needed. GPS pace lies anyway — effort just works better. AUTO-LAP BY DISTANCE OR TIME Distance intervals auto-complete when you hit 200m, 400m, 800m, or whatever target you set. Time intervals count down with precision. No fumbling with lap buttons mid-stride. AUDIO & HAPTIC CUES Get notified at interval start, halfway, and end. Works with your screen off, works on Apple Watch. Built for running outside, where you can't keep glancing at a screen. APPLE WATCH COMPANION Run straight from your wrist. Leave your phone behind for track sessions — the Watch app handles everything on its own. CLEAN, GET-OUT-OF-THE-WAY DESIGN Big, glove-friendly controls. Dark mode. One-screen run view with your current interval front and center, and what's next right there too. AFTER YOUR RUN Review every completed interval — distance, time, pace. Auto-syncs to Apple Health. WORKOUT TYPES Tempo: Sustained-effort training Intervals: Structured speed work Fartlek: Mixed-pace playful running Hills: Uphill repeat sessions Long Run: Extended endurance efforts 3 DURATION OPTIONS Quick (10–15 min): Short, sharp sessions Standard (20–35 min): Complete workouts Long (40–60+ min): Extended training WHO IT'S FOR - Runners looking to improve their times - Runners who like variety and fun - Amateur athletes who want to gain leg strength and power - Anyone looking to improve overall fitness and health - Anyone looking to lose weight with HIIT (High-Intensity Interval Training) - Anyone who wants to run intervals without 10 minutes of setup - Anyone tired of complex running apps that feel more like Instagram No social feeds. No data mining. Just running. Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

OnTrack Interval Timer

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Train Smarter. Run Faster. OnTrack is the ultimate track interval training timer designed specifically for runners who want to hit every pace checkpoint with precision. ā–ø PACE-BASED INTERVALS Set your target pace and distance for each phase. OnTrack automatically calculates the exact time you should hit at every 100m, 200m, 400m checkpoint. ā–ø AUDIO ALERTS Get notified at phase changes, set completions, and distance checkpoints. Never miss a split again - focus on running while OnTrack guides you. ā–ø FLEXIBLE WORKOUT BUILDER Create complex interval structures with: • STEP blocks for simple intervals • REPEAT blocks for sets (e.g., 5 x 1000m) • Warm-up and cool-down phases • Custom rest periods ā–ø PACE CHECKPOINT TABLE Before you start, see exactly what time you should hit at every distance marker. Perfect for track workouts where precision matters. ā–ø WORKS OFFLINE No internet required. Your workouts are stored locally and ready whenever you are. --- EXAMPLE WORKOUT: - Warm-up: 10 min easy - Main Set: 5 x 1000m @ 4:00/km pace (Rest: 2 min) - Cool-down: 5 min easy OnTrack will tell you: • 1000m target time: 4:00 • 100m checkpoint: 0:24 • 200m checkpoint: 0:48 • 400m checkpoint: 1:36 ...and so on! --- Whether you're training for a 5K, marathon, or just want to improve your speed, OnTrack gives you the precision timing you need. Download now and take control of your interval training.

Screenshots

Fartlek4 screens
OnTrack Interval Timer4 screens

Verdict

The call

The clearest difference is iOS requirement: OnTrack Interval Timer at 16.2 against Fartlek's 18.5. On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price Ā· Rating Ā· Positive reviews Ā· Number of ratings Ā· Update frequency Ā· Ads Ā· In-app purchases Ā· Monetization Ā· Best chart rank Ā· Devices Ā· Requires iOS

CostPrice Ā· In-app purchases Ā· Ads Ā· Monetization

Both are free to download. Fartlek sells 2 in-app purchases, starting at $4.99 per month and OnTrack Interval Timer sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Scorecard1 real difference Ā· 5 level
Fartlek versus OnTrack Interval Timer: the parameters behind the verdict, then further details
ParameterFartlekOnTrack Interval Timer
PriceFreeFree
Update frequencyEvery 4 days—
AdsNoNo
In-app purchasesYesYes
DevicesiPhone, Apple Watch — betteriPhone
Requires iOS18.516.2 — better
Further details — not scored
Size29 MB2 MB
Age rating4+4+
DeveloperAxis SAJekal Ik

In-app purchases

2 purchases

Fartlek

Subscriptions2
  • Monthly plan$4.991 Month
  • Yearly Premium$29.991 Year
1 purchases

OnTrack Interval Timer

One-time1
  • Premium - Background Mode$2.99

Questions

Is Fartlek free?
Fartlek is free to download, with in-app purchases available.
Is OnTrack Interval Timer free?
OnTrack Interval Timer is free to download, with in-app purchases available.
Do Fartlek or OnTrack Interval Timer have ads?
Neither Fartlek nor OnTrack Interval Timer shows ads.

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