PEAKVO2 vs a Free Online Interval Timer: App or Browser?
Run these workouts on your iPhone, or hands-free on Apple Watch. Get PEAKVO2 A free online interval timer like IntervalTimer.com runs in your browser with no download, which is perfect for a quick custom HIIT or circuit timer on any device. PEAKVO2 is a native app for iPhone and Apple Watch built around VO2 max, with ready-made protocols, heart rate zones, offline wrist guidance, and VO2 max tracking. Use the browser timer for simplicity; use PEAKVO2 for guided, tracked VO2 max training.
This is not app versus website in a "which is better" sense. They are different tools. A browser timer is the fastest way to get a timer running with nothing installed. A native training app can do things a web page structurally cannot, like run on your watch offline and track your fitness over time. Here is where each fits.
PEAKVO2 vs a Free Online Interval Timer at a Glance
| PEAKVO2 | Online interval timer (e.g. IntervalTimer.com) | |
|---|---|---|
| What it is | Native VO2 max training app | Browser-based interval timer |
| Install | App Store download | None, opens in a browser |
| What you run | Eight ready-made endurance protocols | Custom timers you build, plus presets |
| Named VO2 max protocols | Norwegian 4x4, Tabata, HIIT 30/30, and more | Build your own; not the focus |
| VO2 max tracking | Yes, trend over time | No |
| Heart rate zones | Tied to each protocol | No |
| Apple Watch | Runs natively on the wrist, no phone needed | No native watch app |
| Works offline | Yes, on the watch | Needs the page loaded in a browser |
| Runs on | iPhone and Apple Watch | Any phone, tablet, or laptop browser |
| Price | 3 workouts free, then $0.99/mo, $9.99/yr, $19.99 lifetime | Free |
What a Free Online Interval Timer Is
A free online interval timer such as IntervalTimer.com runs straight in your web browser, with no download and no sign-up. You build your own HIIT, Tabata, circuit, or round timer, placing each interval yourself, or start from a preset, and press start on your phone, tablet, or laptop. You can share the timers you make. It is the browser-based counterpart of the Seconds interval timer app. Its strength is friction: it opens instantly on any device with a browser and costs nothing, which makes it ideal for a quick timer when you do not want to install anything.
What PEAKVO2 Is
PEAKVO2 is an interval training app for iPhone and Apple Watch, built around VO2 max. It ships eight validated endurance protocols, the Norwegian 4x4, Tabata, HIIT 30/30, Billat 30/30, Ronnestad 30/15, VO2 Max 3x3, VO2 Max 5x3, and Tempo Run, with full-screen color-coded phases, automatic transitions, a haptic tap at each switch, and the heart rate zones those protocols depend on. It runs natively on Apple Watch with no phone needed, works offline once a workout is on the watch, tracks your VO2 max trend over time, and includes built-in beep and Cooper field tests. It is a training app, not a testing service.
The Core Difference: A Web Page vs a Native App
A browser timer counts down. That is genuinely useful, and for a quick custom circuit it is all you need. But a web page cannot install itself on your Apple Watch, cannot read the heart rate zones a VO2 protocol depends on, cannot be relied on to run offline when you are out of signal, and cannot track your VO2 max across months of training.
PEAKVO2 can, because it is native. The workout runs on your wrist with haptic cues, so your eyes stay up and the phone can stay home; the protocols come ready to run; and the number you are training, your VO2 max, is tracked over time. If all you want is a timer, a browser is the lighter choice. If you want the training decided, guided on your wrist, and measured, that is what a native app is for.
Who Each One Is For
- Use a free online interval timer when you want a quick, no-install countdown or a custom circuit timer on whatever screen is nearby, and you do not need heart rate zones, VO2 max tracking, or wrist-based guidance. It is free and instant.
- Choose PEAKVO2 if your goal is your aerobic engine: proven VO2 max interval protocols run on your Apple Watch, with the heart rate zones that raise VO2 max, offline reliability, and your VO2 max tracked over time. It fits runners, cyclists, and endurance athletes who want more than a timer.
- Use both if you keep a browser timer bookmarked for ad-hoc circuits and rely on PEAKVO2 for your structured VO2 max sessions.
Build your aerobic engine with PEAKVO2
Guided VO2 max protocols, the Norwegian 4x4, Tabata, REHIT, and more, on iPhone and Apple Watch, with heart rate zones, automatic phases, and your VO2 max tracked over time. Three workouts free.
Get PEAKVO2 free