Monitor Contrast Test
Set your monitor's contrast with one combined pattern, then enter meter readings for an on/off or ANSI ratio. This page does not measure nits. You can also check how contrast holds up off-axis.
Contrast test patterns
Pick a pattern, then go full screen. The contrast setup pattern shows near-white squares, a grey ramp and near-black squares at once, so you can see both ends of the range while you adjust.
Raise contrast until the 250 square merges into white, then back off one notch.
Full screen: click, swipe or press the arrow keys or Space to change pattern, tap a square on the setup pattern to mark it. The X stays visible on white and on black. Esc or the X exits. The browser sends 8-bit SDR values, so this checks contrast as most content uses it, not HDR peak brightness.
Guided contrast setup
Highest white / lowest black you can see
– / –
When you finish, tap the highest white square and the lowest black square you can still see.
Contrast ratio calculator
This page does not measure nits. Read the full white field with a colorimeter or a phone lux app, then the full black field at the same spot (or average the ANSI squares yourself). Type both numbers in the same unit. The ratio is white divided by black, and only when black is above 0.
Contrast ratio
–
Enter a white reading and a black reading above 0.
Compared (log scale, 100:1 to 100,000,000:1)
- IPS~1,000:1
- VA~3,000:1
- Mini-LED (dimming on)~20,000:1+
- "Dynamic contrast" on the box100,000,000:1
- OLEDpixels switch off
Understanding contrast
How to set contrast
Contrast sets how bright the top of the signal is drawn. Too high and levels 245 to 254 all hit the panel's maximum, so clouds, snow and skin highlights flatten into one white. Too low and white looks grey. The sweet spot is the highest setting where 250 is still visible. Set brightness first on the black squares, because on many monitors the two controls interact. For a deeper look at each end, use the white level test and the black level test.
Dynamic contrast is marketing
A box that says 100,000,000:1 is quoting dynamic contrast: the brightest full-white frame divided by the darkest full-black frame, with the backlight dimmed to almost nothing in between. You never see both at once, so it says nothing about a real picture. Native (static) contrast is the number that matters: around 1000:1 for IPS, 3000:1 for VA, and effectively infinite for OLED, whose pixels switch off.
ANSI vs. full on/off
Full on/off compares a white screen with a black screen. ANSI contrast measures both at once on the 4×4 checkerboard, so light from the white squares spills into the black ones. On a plain LCD the two numbers are close. With local dimming, full on/off can look huge while ANSI drops sharply, because the zones cannot be dark and bright side by side. That gap shows up as blooming: halos around bright objects on a dark background. Check halos and backlight spread with the screen uniformity test.
Measuring tips and viewing angle
Measure in a dark room, at your normal brightness, with any dynamic or eco mode off, and keep the meter on the same spot for both readings. A phone lux app is fine for white but bottoms out on black, so its ratio is a lower bound. Ambient light reflecting off the screen lowers the contrast you actually see far more than the spec sheet admits. On the viewing angle pattern, IPS holds its greys off-axis, VA washes out and shifts shadows, and TN changes strongly when viewed from above or below. Pair this with the brightness test.
Related tools
- White Level Test: find exactly where highlights clip.
- Black Level Test: set brightness so shadows are not crushed.
- Brightness Test: check and set screen brightness.
- Screen Uniformity Test: spot clouding, vignetting and blooming.
Contrast ratio = white reading ÷ black reading, only after you enter both and black is above 0. Any unit works if both readings use the same one. This page does not measure nits itself.
Frequently asked questions
How do ANSI and full on/off differ on this page?
Both use the same math: the white number you type divided by the black number you type. The method menu does not change that division. Full on/off is the solid white field, then the solid black field, at the same spot. ANSI is the 4×4 checkerboard. Average the white squares and average the black squares yourself, then type those two numbers, because light from the white squares spills into the black ones. Choosing ANSI only adds a note that ANSI readings run lower than full on/off on screens with local dimming, so compare like with like. On a plain LCD the two stay close. With local dimming, full on/off can look much higher while ANSI falls. That gap is blooming.
Why do dynamic contrast claims differ from this calculator?
A box figure such as 100,000,000:1 is dynamic contrast. The chart row "Dynamic contrast" on the box uses that same figure. It divides the brightest full-white frame by a full-black frame taken after the backlight is dimmed. You never see both at once, so it is not the contrast of one picture. This calculator divides two readings you type, taken with dynamic contrast, local contrast enhancement, eco mode and the ambient light sensor off. The IPS, VA, mini-LED and OLED rows are reference marks drawn on the page, not numbers this page measured.
How do I leave full screen?
Press Esc, or press the X at the bottom. The X stays visible and tappable on white and on black. It does not fade out. Arrow keys, Space, Enter, Page Up, Page Down, Backspace, a click or a swipe change the pattern. They do not close the test. If the browser will not enter full screen, the same overlay still covers the page, and Esc or the X closes it. Leaving full screen with the browser control closes the test too.
What happens if the black reading is 0?
The page will not divide by zero, and it will not show an infinity symbol. A ratio appears only after you enter both readings, with white above 0 and black above 0 and lower than white. A meter that shows 0 has not resolved black. That can happen on OLED, where pixels switch fully off, or when the meter cannot read low enough. Type a black reading above 0 if you have one. This page does not measure nits or lux itself.
Does this page measure the contrast ratio?
No. It draws patterns in the browser as 8-bit SDR colour. It cannot read the panel, the room or a brightness in nits. You measure white and black with a colorimeter (nits) or a phone lux app, then type both numbers in the same unit. The result is those two numbers divided. If you pick lux and the black reading is above 0 and at most 2, the page warns that phone sensors are coarse there, so treat the ratio as a lower bound.
How do I set contrast with the setup pattern?
Use Standard, sRGB or Custom, and switch off dynamic contrast, local contrast enhancement, eco mode and any ambient light sensor. On the black squares, set brightness until 1 or 2 merges into the black strip but 3 or 4 is just visible. Raise contrast until the 250 square merges into white, then back off one step so 250 shows again. 252 to 253 should show faintly too. The grey ramp is 17 bands from 0 to 255. Tap the highest white step and the lowest black step you can still see. The note says highlights are set well at 252, 253 or 254, and fine at 250. Shadows are in a good place at 1, 2, 3 or 4. Marking 6 or 8 says to raise brightness a little. Marking 12 or 16 says blacks are crushed.