Free vision screener · no signup · 8 languages

Check your vision online, eye by eye.

Calibrate your screen, stand at the right distance, cover one eye at a time and read the smallest line you can. Eleven vision checks, eye by eye, in about ten minutes.

Start the free online eye test View all checks
  • Nothing to install or sign up for
  • Results never leave your browser
  • About ten minutes, eye by eye

A vision screener — not an official medical test, a diagnosis or a prescription.

Snellen chart · 6 m 20/40 pass line
Screen calibrated Stand 3 m away
20/40gen.hero.badgeA
Left eye firstCover, read, swap
  • 11vision checks
  • 20/40unrestricted benchmark
  • 8languages
US

US driver?

Practise the DMV eye test: 20/40 benchmark, all 50 state vision rules and CDL prep.

Start the US DMV practice test

How it works

Ten minutes, replicated procedure

The order matches what happens at the counter: calibrate, distance, occlude, read. Do it the same way each time and the numbers mean something.

  1. 01

    Calibrate your screen

    Hold a bank card against the on-screen outline and slide until the sizes match. That turns millimetres into pixels so the letters are the real size.

  2. 02

    Set your distance

    Pick 3 m or 6 m, mark the spot on the floor, and dim the room. Bright screens and short distances flatter your eyes.

  3. 03

    Cover one eye

    Cup — never press — one eye with your palm, then the other. Both eyes together are tested last.

  4. 04

    Read the smallest line

    Type or tap the letters you actually see. Miss twice in a row and the screener stops you there — guessing hides the problem you came to find.

What gets checked

Eleven checks for distance, colour and near vision

Jump straight into any single check, or run the full sequence.

The screener

Run the full check

Work through it in order. Nothing is uploaded — the whole screener runs on this device.

Ready when you are

    Ready when you are

    Evidence & standards

    Built on the tests eye professionals actually use

    Every check follows a published protocol. None of them diagnose anything on their own — they exist so you arrive at your appointment prepared.

    Sources & further reading

    Questions

    Before you start

    Does this count as an official test?
    No. It is a practice screener, so you arrive prepared. The official check is done by an examiner with their own equipment, and that is the only result that counts.
    Can it replace a visit to an optometrist?
    No. Nothing on a screen can diagnose a condition or produce a prescription. If your results worry you, see an optometrist.
    Should I wear my glasses or contacts?
    Yes. Test with the correction you drive in — the center tests corrected vision, and your licence will carry the appropriate restriction.
    Why do I have to calibrate the screen?
    Letter sizes are computed in millimetres. Uncalibrated, a 20/40 letter on your monitor is not a real 20/40 letter. A bank card is enough to set the scale.
    How far away should I sit?
    Three metres fits most rooms; six metres is the Snellen standard. What matters is measuring once and always returning to the same spot.
    Are my results stored anywhere?
    Only in this browser. There are no accounts, no advertising trackers and no uploads. You can clear them whenever you like.
    What is the duochrome test?
    The same letters are shown on a red and a green background. If they look sharper on red, your eye is focusing slightly in front of the retina (short-sight); on green, slightly behind (long-sight). Opticians have used it for a century to fine-tune a prescription.
    Can this tell me my prescription?
    No. The refraction and astigmatism checks give a screening hint about the direction of any error, and nothing more. Only a qualified optometrist with a phoropter and trial lenses can issue a prescription.
    Why can I not see the hidden shape?
    About one person in ten cannot free-view an autostereogram, and it also fails if one eye is much stronger than the other or if you cannot fuse the two images. Not seeing the shape is not by itself a diagnosis — but it is worth mentioning at your next eye exam.

    Vision check

    Free online vision test: what the screening actually covers

    What the screening actually covers

    The flow mirrors an in-person eye exam: calibrate your display with a standard card, step back to the designated distance, cover one eye with your palm, and identify the smallest row of optotypes. Following visual acuity, the screener guides you through Tumbling-E orientation, color recognition plates, 60° and 75° peripheral awareness, 16-inch near vision, contrast sensitivity, an astigmatism dial, and a red-green duochrome check. The primary target benchmark is 20/40 visual acuity — the standard required by most driver licensing agencies for unrestricted driving.

    How to get an accurate result at home

    Accuracy depends entirely on physical pixel dimensions. Uncalibrated online charts can be distorted by 30% or more, turning a true 20/40 line into an apparent 20/25. By placing a standard magnetic card (85.6 mm under ISO/IEC 7810) against the screen outline and adjusting the slider, the software translates screen millimeters into exact angular dimensions, rendering vector letters with calibrated millimeter precision.

    Preparing your testing environment

    Position yourself exactly 10 feet (3 meters) away, or 20 feet (6 meters) if space allows for standard Snellen testing. Mark your spot on the floor so your position stays consistent. Dim ambient room lighting so the monitor is the clearest light source in your field of view, keep the screen at eye level, and avoid leaning forward to guess optotypes — viewing distance is a fundamental part of the measurement.

    Why calibrated vector optotypes beat static images

    Static image charts rely on fixed pixel resolutions that change physical size depending on screen resolution and scaling. Two people viewing the same image on different laptops will see vastly different visual angles. Calibrated vector optotypes scale dynamically on a 5x5 Snellen grid, ensuring identical arcminute substructures across all devices.

    Medical disclaimer and purpose

    This screening tool is designed for personal practice and educational self-check. It is not an official DMV or DOT examination, not a clinical eye exam, and cannot replace a comprehensive medical evaluation by a licensed optometrist or ophthalmologist. If you notice persistent blur, double vision, or discomfort, schedule an examination with an eye care professional.