1·SecondLapOpen the web stopwatch

    1SecondLap for iOS

    One app for your
    whole workout.

    A GPS run tracker, interval timer, Bluetooth gym-machine console and reflex trainer in one free app. No account, no ads, no subscription — and everything you record stays on your phone.

    This page describes the iOS app for iPhone and Apple Watch, coming soon to the App Store. An Android version is in development.

    Coming sooniPhone & Apple WatchFreeNo accountNo adsWorks offline
    1SecondLap tracking a run: 1.24 km at 4:59 per km, racing a ghost run seven seconds behind the personal best, with a 5 km goal progress bar.

    Run outdoors

    Runs, walks and rides with a coach in your ear

    Pick Run, Walk or Ride and press Start. The app tracks distance, pace and your route by GPS, and calls out every kilometre so you never have to look at the screen.

    • Ghost runs. Run a route you have run before and race the ghost of your best attempt, hearing how far ahead or behind you are as you go.
    • Spoken pace coach. Set a target pace and get “speed up” and “slow down” cues whenever you drift off it.
    • Routes and splits. Every session is saved with its map and per-kilometre splits, with your fastest kilometre highlighted.
    • Distance goals and GPX export. Set a goal with progress announcements along the way, and export any run as a GPX file for another app.
    • Screen-locked tracking. Tracking keeps running with your phone locked, and a Live Activity shows time, distance and pace on the Lock Screen.
    A saved 8.02 km run in 40:43 at 5:05 per km, shown with its route on a map, a GPX export button, and a per-kilometre splits breakdown.

    Interval workouts

    Voice-coached intervals, and a trainer that follows along

    Build a workout from reps, work and rest periods and get a spoken countdown into every phase. Tabata, HIIT, EMOM and boxing templates are built in, and you can save your own.

    • Your own presets. Save any combination of reps, work and rest and start it again with one tap.
    • Hands-free. Get-ready countdowns and phase changes are announced out loud, so the phone can stay in your pocket.
    • ERG mode. With a compatible smart trainer connected, the app sets the trainer’s resistance for you — one wattage for work, another for rest, switching automatically as the workout runs.
    An interval workout mid-session: a large orange progress ring counting down nine seconds of a work phase, round 1 of 8, above a total progress bar.

    Gym machines

    Your phone as a machine console

    Connect Bluetooth fitness equipment over the standard FTMS and CSC protocols and read everything the machine reports — live, and saved to your history afterwards.

      Bikes, treadmills, rowers, cross-trainers

      Live cadence, power, speed, stroke rate and distance from the machine itself.

      Heart-rate straps

      Live BPM with your zone, spoken zone cues, and a time-in-zone breakdown per session.

    Progress

    See the training add up

    An activity heatmap, weekly volume by activity type, and a training-load view built from your heart-rate data — including a nudge when you ramp up faster than usual.

    • Volume and load. Weekly totals split by outdoor, machine and workout sessions, with training load weighted by heart rate.
    • Trends and records. Pace, power and reaction-time trends with personal records and streaks.
    • Apple Health. Completed workouts, runs and rides are written to Apple Health with your permission.
    The Progress overview: an activity heatmap showing 62 active days, a weekly volume chart split by outdoor, machine and workout sessions, and a training load panel reading 387 this week against a usual 247.

    Brain + body

    What exercise does to your reflexes

    Because the app times both your workouts and your reflexes, it can show you something few fitness apps can: how your reaction time actually responds to training.

    • Exercise × reaction time. The app splits your tests into those taken after a workout and those taken at rest, and shows you the gap.
    • Four reflex games. A classic reaction-time test plus an aim trainer, a sequence-memory game and a Stroop colour–word test.
    • Tracked over time. Every result is saved, so improvements show up as a trend rather than a single lucky tap.
    The Brain trends tab: a card comparing 232 ms average reaction time after exercise against 259 ms at rest, noting 10 percent faster within two hours of a workout, above a reaction-time trend chart.

    Beyond the phone

    On your wrist and your Lock Screen

    • Apple Watch. Stopwatch, timer and interval workouts on your wrist, with the same voice cues.
    • Home Screen widget. Your most recent session summary, without opening the app.
    • Live Activities. An active run or workout stays visible on the Lock Screen.
    The 1SecondLap Apple Watch app showing a running stopwatch.

    Platforms

    iOS first, Android next

    Everything on this page refers to the iOS app for iPhone and Apple Watch, which is coming soon to the App Store. An Android version is in development; some features described here rely on Apple-specific integrations such as Apple Health, Live Activities and the Apple Watch app, so the Android feature set will differ. In the meantime the stopwatch, timer, interval workouts and reflex tests all run in any mobile browser.

    iOS

    Coming soon

    iPhone and Apple Watch, with widgets, Live Activities and Apple Health.

    Android

    In development

    No release date yet. The feature set will be announced when it ships.

    Web

    Available now

    Stopwatch, timer, interval workouts and reflex tests in your browser.

    Your data never leaves your phone

    There is no account and no server. Laps, workouts, routes, heart-rate and sensor readings are stored only on your device, and the iOS app contains no analytics, no advertising and no third-party tracking of any kind. Uninstalling removes all of it.

    Read the full privacy policy
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