Contrast Test

A monitor contrast test checks whether your display renders the full range from pure black to pure white without losing detail at either end. Using our tool, you view a 16-step shadow grid (values 0–51), a 16-step highlight grid (values 204–255), and black/white reference squares. You count how many steps you can distinguish. A healthy display shows 14–16 steps in each grid. Missing steps mean crushed blacks (dark detail lost) or clipped whites (bright detail lost), usually fixable through brightness and contrast settings.

Testing takes about two minutes: (1) Reset your monitor picture mode to Standard or sRGB and set normal brightness. (2) Click "Start Test" above and open the Shadow Detail grid. (3) Count the dark boxes you can tell apart from black — aim for 14–16. (4) Open the Highlight Detail grid and count bright boxes distinguishable from white. (5) Check both reference squares (#0A0A0A on black, #F5F5F5 on white) — each should be just barely visible. (6) Adjust brightness for blacks and contrast for whites, then re-test.

Crushed blacks happen when near-black gray tones all display as pure black, so dark scenes lose texture — for example, folds in a black jacket disappear or night scenes become flat voids. The most common causes are brightness set too low, an aggressive gamma curve, "black stabilizer" gaming modes, or a limited-range (16–235) GPU signal feeding a full-range display. To fix it, raise brightness one notch at a time until the #0A0A0A reference square becomes just visible, then verify with the shadow grid.

Clipped whites (white saturation) happen when near-white gray tones all display as pure white, so bright detail disappears — clouds lose shape, wedding dresses become flat blobs. The usual cause is the contrast setting pushed too high, common in "vivid" or store-demo picture modes. To fix it, lower the contrast setting gradually until the #F5F5F5 reference square reappears against the white background, then verify with the highlight grid. Aim for 14–16 distinguishable highlight steps.

On a well-calibrated 8-bit display you should distinguish 14–16 of the 16 steps in each grid. Seeing 12–13 steps is acceptable for everyday use and rarely noticeable in real content. Fewer than 10 visible steps indicates a real problem — crushed blacks or clipped whites worth fixing through monitor settings. Note that losing only the single darkest step (0 vs 3) or the single brightest step (255 vs 252) is normal on consumer panels and not a defect.

Typical native contrast ratios: TN panels 600–1000:1, IPS panels 1000–1500:1, VA panels 3000–5000:1, and OLED effectively infinite:1 since each pixel turns fully off. Higher numbers mean deeper blacks. However, the ratio alone does not guarantee visible detail — a high-contrast panel can still crush near-black steps with a bad gamma curve. That is why this step-count test matters more than the marketed ratio: it measures the detail you actually see.

Washed-out dark scenes usually mean one of three things. First, a limited-range (16–235) vs full-range (0–255) mismatch between your GPU and monitor — black is rendered as dark gray. Fix it by setting both sides to Full/RGB 0–255. Second, IPS glow or backlight bleed lifting the blacks in a dark room (use our Screen Bleeding Test to check). Third, brightness set far too high. Work through them in that order: range match, bleed check, then brightness calibration with the #0A0A0A reference.

Yes. On a phone, open this page in the mobile browser, dim the room slightly, and run the shadow grid — OLED phones should show near-perfect step separation. On a TV, open the page in the built-in browser or cast it from a laptop, then disable "vivid", "dynamic contrast", and energy-saving modes first, since those distort the test. For TVs also test with local dimming on and off: aggressive dimming can crush small shadow steps while improving headline contrast numbers.

Completely safe. The test displays static gray patterns, but a two-minute manual check cannot cause burn-in — OLED burn-in requires thousands of hours of the same static bright element. Unlike "pixel fixer" videos that flash harsh strobing colors for hours, this tool uses calm static patterns. All rendering is local CSS with zero network activity, and there is no camera or screenshot access of any kind.

Yes, because HDR moves the reference points. In SDR the scale runs from 0 to 255 and the shadow grid applies directly. In HDR the display follows a perceptual transfer curve such as PQ or HLG, so the darkest steps sit at different code values and a black that looks correct in SDR can look lifted in HDR. Test both modes separately: confirm the SDR shadow grid first as your baseline, then switch the operating system and the display to HDR and run the grid again, letting the panel settle for a minute. If shadow steps vanish only in HDR, the tone-mapping curve is too aggressive, and lowering peak brightness usually recovers the lost steps.

Use the brightness you actually work or watch at, because a contrast result only means something at realistic settings. For an office that is typically 120 to 150 nits, in a bright room 200 to 250 nits, and in a dim room for film or photo work around 100 to 120 nits. Photo editing usually targets 120 nits with a 6500K white point so that prints match the screen. Do not test at maximum brightness, since that clips highlights and makes shadows look artificially clean. Set brightness first, then adjust the contrast control to recover the brightest reference square, and remember that on most LED displays the backlight control is the only true brightness adjustment.

You can get close with patterns alone, which is exactly what this test is for, but you cannot measure an absolute number without a meter. Visual calibration can set black level, white saturation, and a rough gamma target reliably enough for everyday use, gaming, and streaming. A hardware colorimeter is needed when the result must be verifiable: matching two displays, preparing print work, or documenting a calibration report. A useful middle path is to use the shadow and highlight grids for the eyes-on adjustment, then verify the white point with a pattern-based gray reference. If a professional workflow depends on the result, borrow or buy a meter and verify what you set visually.