Comparison

Seconds Interval Timer vs VO2 Flow

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

Head to head
About

Seconds Interval Timer

This app provides a versatile interval timer for various workout types like Tabata, HIIT, and circuit training. It features a clear, full-screen display, customizable alerts, and background operation. Users can also utilize a stopwatch and countdown timer, with integration for Apple Health.

Highlights
  • Full-screen colored display
  • Templates for HIIT, Tabata, Circuit Training
  • Voice and audio alerts
  • Music assignment per interval
  • Background operation
  • Apple Health integration
  • Stopwatch and countdown timer
Features
Read full description

Seconds is an interval timer for HIIT, Tabata, EMOM, circuits and any workout built from timed intervals. It calls each interval out loud, keeps running with the screen off, and runs on iPhone, iPad and Apple Watch. Apple has featured it, and Joe Wicks, The Body Coach, has said it is the fitness app he uses more than any other. BUILD ANY WORKOUT - Start from a HIIT, Tabata or circuit template, or build a timer from scratch with sets, rounds and intervals of different lengths. - Chain timers into one compound timer, so a warm-up flows into the main set and then a cool-down. - Color-code every interval so you know what is coming before the beep. - Share a timer with a friend in one tap. HEAR IT, DON'T WATCH IT - Voice cues call out each interval by name and warn you before the next one starts. - Beeps and bells are there too if you would rather not be talked at. - Play your own music, per timer or per interval. Cues duck the music and it comes back up when they are done. - The timer keeps going in the background while you use other apps or the screen sleeps. ON THE GYM FLOOR - A full-screen, color-coded display you can read from across the room, in portrait or landscape. On iPad it uses the whole screen. - A lock button stops a stray tap from pausing your set. APPLE WATCH - Seconds runs on the watch by itself, so the phone can stay in the locker. Timers you build on the phone sync to the wrist, and Quick Intervals builds a basic circuit on the watch itself. MORE TIMERS - A stopwatch that marks your best and worst laps. - A countdown timer with five preset durations (three on Apple Watch). APPLE HEALTH - Save workouts and mindful sessions to Health. With a heart rate monitor connected, Seconds reads your body measurements and year of birth from Health to estimate calories burned. FREE TO TRY, ONE PAYMENT TO UNLOCK - Everything is available from the first launch. Build any timer and run it. - Each timer locks after you run it once. A single in-app purchase removes the lock on every timer you make. SECONDS AND SECONDS PRO - Seconds Pro is the same app, paid once up front, with nothing to unlock. The two are separate products and a purchase in one does not carry over to the other. If you bought Seconds Pro, download Seconds Pro. If you bought the unlock in Seconds, download Seconds and use Restore Purchases.

About

VO2 Flow

Features
Read full description

VO2 Flow is built for the Norwegian 4x4 protocol, the research-backed interval method athletes use to raise VO2max. Four 4-minute intervals at 90 to 95% max heart rate, with 3-minute recoveries. Studies show a 10% VO2max increase in 8 weeks. Run Norwegian 4x4 or build your own protocol. Tabata. 10x1. 8x2. Any work and rest combination, any number of rounds. Free in the app: - Norwegian 4x4 protocol built-in and ready to start - Workout history, every completed session logged and grouped by month - One custom interval profile - Apple Music integration, album art and controls during your session - Audio cues and haptic feedback on every phase transition - Keep screen awake during workouts - Landscape and portrait support Pro upgrade, $4.99 one-time: - Remove all ads forever - Unlimited custom interval profiles - Achievement badges, 7 milestones you can share - Every future Pro feature, no subscription This is a timer, not a fitness platform. No social feed. No subscription. No complexity. Launch, pick a profile, start.

Screenshots

Seconds Interval Timer4 screens
VO2 Flow4 screens

Verdict

The call

The clearest difference is ads: Seconds Interval Timer at none against VO2 Flow's shown. VO2 Flow's advantage is iOS requirement (13.0 vs 18.0). On price, update cadence, in-app purchases and device support 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. Seconds Interval Timer sells 1 one-off in-app purchase and VO2 Flow sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Seconds Interval Timer ships an update monthly, VO2 Flow every 5 weeks. The most recent releases landed on October 18, 2026 and September 25, 2026 respectively.

Scorecard2 real differences · 8 level
Seconds Interval Timer versus VO2 Flow: the parameters behind the verdict, then further details
ParameterSeconds Interval TimerVO2 Flow
PriceFreeFree
Rating4.7 (24K ratings) — better—
Positive reviews74.5% of reviews—
Number of ratings24K — better—
Update frequencyMonthly — betterEvery 5 weeks
AdsNo — betterYes
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, Apple WatchiPhone, iPad, iPod
Requires iOS18.013.0 — better
Further details — not scored
Size95 MB25 MB
Age rating4+4+
DeveloperRunloop LtdCHRISTOPHER DISCOTTO

Bugs and requests

Seconds Interval Timer

Reported bugs

2 issues
  • Timer sometimes stops working unexpectedly
  • Issues with restoring purchases on new devices

Requested features

5 requests
  • Ability to change beep/alert volume independently
  • Option to delay transition between intervals
  • Sync workouts across devices
  • More preset workout templates
  • Heart rate monitoring integration

VO2 Flow

Not enough reviews yet to summarise bugs or requests.

In-app purchases

1 purchases

Seconds Interval Timer

One-time1
  • Advanced Version$7.99
1 purchases

VO2 Flow

One-time1
  • Pro Upgrade$4.99

Questions

Is Seconds Interval Timer free?
Seconds Interval Timer is free to download, with in-app purchases available.
Is VO2 Flow free?
VO2 Flow is free to download, with in-app purchases available.
Do Seconds Interval Timer or VO2 Flow have ads?
VO2 Flow shows ads; Seconds Interval Timer does not.
Which is updated more often, Seconds Interval Timer or VO2 Flow?
Seconds Interval Timer ships an update monthly, and VO2 Flow every 5 weeks. Most recently, Seconds Interval Timer was updated on October 18, 2026 and VO2 Flow on September 25, 2026.

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