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Start Lights Reaction Test

Five red lights come on one by one, then all go out at once: tap the moment they go dark and this race start reaction test shows your time in milliseconds.

    Chart: your rounds
    Settings

    How to use the start lights reaction test

    Tap the dark panel, click it or press Space to begin a start. The five lights then come on from left to right, one each second. Once all five are lit, keep still: after a short hold that changes every time, they all go out together. That is your cue. Tap, click or press Space as quickly as you can, and your reaction time appears under the gantry in milliseconds.

    Moving early is a Jump start: any press while a light is still on, or before the first one appears, cancels that start and it is not counted. Your next tap begins a fresh sequence. A round has 5 counted starts by default; choose 3 or 10 at the top of the panel. At the end of a round you see your average, your quickest and your slowest start, plus how many jump starts you made along the way.

    Your best average for each round length and your quickest single start stay in your browser with your last 300 results. Download CSV exports them, Undo takes back the last saved round, and Clear results wipes everything with an undo button in the message. Share link sends a friend your best average as a time to beat. If you would rather react to a box turning green, a beep, or a green or red choice, use the reaction time test.

    How the start sequence works here

    This tool lights one lamp column per second, so the fifth light comes on 5 seconds after your start press. It then waits for a random hold of 0.2 to 3 seconds, picked evenly from that range for every start, before switching all five off in the same frame. The hold is this tool's own setting, chosen so that counting the lights in your head cannot tell you when they will go out. It is not an official timing from any racing series.

    The five-light start is the kind used in Formula 1 and other motor racing, and this page is a game inspired by it. It is an unofficial game and is not affiliated with Formula 1 or the FIA.

    Your time runs from the screen frame in which the lights go dark to the moment your press reaches the browser, using the press's own time stamp. Your screen, mouse, keyboard or touch screen all add a little delay of their own, so compare times taken on the same device. With sounds on, a short tick plays as each light comes on; nothing plays at lights out, so you have to watch.

    Keyboard shortcuts

    A key held down never counts twice, and a press is read on key down, not when you let go.

    Questions

    What counts as a jump start here?

    Any press after you start a sequence and before all five lights have gone out. That start is not counted, the jump start total for the round goes up by one, and your next tap starts a new sequence.

    Why is the wait after the fifth light different every time?

    So you cannot time it. This tool picks a new hold between 0.2 and 3 seconds for each start. It is our setting for this game, not a figure from any racing rule book.

    Is this an official F1 reaction test?

    No. It is an unofficial lights out reaction test inspired by the five-light start used in motor racing, and it is not affiliated with Formula 1 or the FIA. It shows how fast you react on your own device.

    Can I race a friend?

    Yes. Finish a round, then use Share link. Whoever opens it gets your best average for that round length as a time to beat, and their own results stay as they were.

    Are my times sent anywhere?

    No. Every result and setting is saved in your browser only, and nothing is sent anywhere.

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    Put this start lights reaction test on your website

    Free for classrooms, clubs, blogs and shops: paste this code into any page. It works the same inside your site, and counts stay in each visitor's own browser. For a dark version, add ?theme=dark after /start-lights-reaction-test/ in the code.