Comparison

RUN interval vs Zelos.Fitness

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

Head to head
About

RUN interval

This app simplifies interval and Fartlek running by allowing you to set custom targets for time or distance during hard, easy, and rest efforts. It offers detailed post-run summaries, audio and visual feedback, and an Apple Watch app for enhanced training.

Highlights
  • Customizable interval sessions
  • Time and distance targets
  • Distance Goal option
  • Audio and visual feedback
  • Detailed run summaries
  • Apple Watch app
  • Strava sharing
Features
Read full description

Easily set up and record your Interval and Fartlek running sessions. With the flexibility of using time and/or distance as interval targets for your "Hard", "Easy" and "Rest" efforts. The simple but highly configurable interface on your phone and watch will have you running sooner. Now with a Distance Goal option for your session. Along with great audio and visual feedback, detailed post-run summary, share your runs to Strava, and a full-featured Apple Watch app. You can also record your regular runs with voice-over calling out distance and pace feedback. Key Features: • Easily create flexible custom interval sessions. • Utilize three effort targets "Hard", "Easy" and "Rest" in each set, targeting time or distance (meters or miles). • You can "Skip" any of the three efforts to create flexible sets, like building a progressive intervals session. • NEW: Set a Distance Goal for your session, that repeats the sets from the start until the distance has been reached. • Set a Warm-Up and Warm-Down timer or distance around your session. • Clear and easily glanceable visuals and audio prompts, including vibrations. • Voice-over prompts to save you from looking at the screen, great for iPhone or headphone users. • Voice-over prompts include the upcoming intervals effort and time/distance amount, and your last intervals average pace and heart rate. • Full-featured Apple Watch App! • Heart Rate Zones! (see description below) • Indoor Mode, no GPS, for treadmill running. • Sound Mode, for normal, discrete or silent audio prompts on your watch. • Vibration feedback on both the phone and watch. • Detailed run summary, showing pace for hard and easy efforts. • The run summary also includes interval breakdown, distance breakdown and heart rate details. • Play music or podcasts while running and still hear the audio prompts. • Sharing. Share a summary photo with your friends. • Private data. We don’t send any of your data to a server or share it with anyone. Session Types: • Normal Run – Record a normal run, long or short. • Record Intervals – If you run with a group or do an undefined session, then use the Record Interval option. It allows you to manually change between "Hard" and "Easy" reps, allowing you to record your session. • Custom Intervals – Our fully flexible intervals that allow you to use time and/or distance for the efforts. Add multiple intervals sets together to create the session you want. Sharing: From the summary screen, you can share your runs with friends or across social media. If you want to share directly with friends or across other social media, you can share a summary image with the details of your run. Heart Rate Zones: (Apple Watch Only) Zones are displayed as grouped percentages of your maximum heart rate. Giving you an indication of your current work rate based on your current heart rate. Just enter your maximum workout heart rate into our Settings screen and they will display on your Watch the next time you run. Zone 1: Very Light Effort 50-60% (Gray) Zone 2: Light Effort 60-70% (Blue) Zone 3: Moderate Effort 70-80% (Green) Zone 4: Hard Effort 80-90% (Yellow) Zone 5: Maximum Effort 90-100% (Red) Privacy: We don’t want to know where you have run, that's for you to worry about. We don’t send any of your data to a server or share it with anyone you don't want too. We keep your running records safe in Apple Health so you have control. Apple Heath gives you the control over who accesses your data. We only write and read the data we record from your running. Feedback: And because we don't send any data to a server, we need you to send us feedback and suggestions. Hit the Support link below or visit our website to contact us.

About

Zelos.Fitness

Features
Read full description

Zelos is where your coach programs your training, and where you log every rep of it. You need an invitation from a coach to use Zelos. If you do not have one yet, ask your trainer. WORKOUTS Your coach builds your week. Today's session is there the moment you open the app, with every set, rep, and target already in place. Log as you go with one tap per set, add a note when something felt off, and record a form video for your coach to review. NUTRITION Log food against the macro targets your coach set for you. Search a catalog of more than 13,000 foods carrying full micronutrient data, save the meals you eat often and log them again in one tap, and carry different targets on training days and rest days. CARDIO AND APPLE HEALTH Connect Apple Health and your runs, rides, and rows appear on their own, with heart rate zones and daily calorie burn. Your coach prescribes cardio and a matching activity completes it for you. No watch? Log it by hand. CHECK-INS Submit weekly check-ins with body metrics and progress photos. Your coach reads them and replies in the app. MESSAGES Talk to your coach directly. No email threads, no screenshots lost in a camera roll. Zelos is a coaching tool, not medical care. Nothing in the app is medical advice, and nutrition figures are approximate. Talk to a qualified professional before starting a new training or nutrition program. Zelos never uses your Apple Health data for advertising, never sells it, and never writes it to iCloud. Privacy URL: https://zelos.fitness/privacy

Screenshots

RUN interval4 screens
Zelos.Fitness3 screens

Verdict

The call

The clearest difference is in-app purchases: Zelos.Fitness at none against RUN interval's 2. Zelos.Fitness also leads on update cadence (weekly vs every 3 months). On price, ads, device support and iOS requirement there is nothing between them.

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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. RUN interval sells 2 one-off in-app purchases. Zelos.Fitness asks for nothing beyond the download.

UpkeepUpdate frequency

RUN interval ships an update every 3 months, Zelos.Fitness weekly. The most recent releases landed on November 2, 2026 and October 31, 2026 respectively.

Scorecard2 real differences · 8 level
RUN interval versus Zelos.Fitness: the parameters behind the verdict, then further details
ParameterRUN intervalZelos.Fitness
PriceFreeFree
Rating4.7 (1K ratings) — better—
Positive reviews77.1% of reviews—
Number of ratings1K — better—
Update frequencyEvery 3 monthsWeekly — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPod, Apple Watch — betteriPhone, iPod
Requires iOS15.615.0 — better
Further details — not scored
Size34 MB9 MB
Age rating4+4+
DeveloperCAN YOU HEAR ME SOFTWAREZelos Fitness Inc

In-app purchases

2 purchases

RUN interval

One-time2
  • The full RUN interval$1.99
  • The full RUN interval$3.99
None

Zelos.Fitness

No in-app purchases

Questions

Is RUN interval free?
RUN interval is free to download, with in-app purchases available.
Is Zelos.Fitness free?
Zelos.Fitness is free to download, with no in-app purchases.
Do RUN interval or Zelos.Fitness have ads?
Neither RUN interval nor Zelos.Fitness shows ads.
Which is updated more often, RUN interval or Zelos.Fitness?
RUN interval ships an update every 3 months, and Zelos.Fitness weekly. Most recently, RUN interval was updated on November 2, 2026 and Zelos.Fitness on October 31, 2026.

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