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Screen size calculator
Calculate pixels per inch (PPI), physical width and height, and display area from a monitor or laptop diagonal and its native resolution. Compare common 24-inch, 27-inch, 32-inch, ultrawide, and laptop presets.
Screen Parameters
Pixel Density
91.79 PPI
Physical Dimensions
- Physical Width
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- Physical Height
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- Aspect Ratio
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- Display Area
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Common Sizes
Load popular monitor and laptop presets.
Unit Converter
Diagonal inches ↔ centimeters.
Screen size & PPI calculator tool
Diagonal-to-PPI math, physical width and height in inches and centimeters, display area, and common monitor presets — all in your browser, no install required.
PPI from diagonal + resolution
Enter the advertised diagonal and native pixel grid. The calculator derives pixels per inch so you can compare sharpness across panels of the same size.
Physical dimensions
See real width, height, and area — not just the marketing diagonal. Ultrawide panels share a diagonal with shorter 16:9 sets but need more desk space.
Presets & unit conversion
Load 24″ FHD, 27″ QHD, 27″/32″ 4K, ultrawide, and laptop presets, then read inches and centimeters side by side.
What screen size and PPI mean
Diagonal inches, resolution, and pixel density work together. Understanding each term helps you read the calculator results correctly.
Diagonal (inches)
The manufacturer size measured corner-to-corner across the active image area — not the bezel. Browsers cannot measure this; you enter it from the spec sheet.
PPI (pixels per inch)
How densely pixels pack along the diagonal: √(width² + height²) ÷ inches. Higher PPI usually means sharper text when OS scaling is set sensibly.
Physical width & height
Derived from the diagonal and pixel aspect ratio. Useful for mounts, dual-monitor arms, and laptop bag clearance when diagonal alone is misleading.
How to use the screen size calculator
Three steps: enter the panel diagonal and resolution, read PPI and physical size, then compare presets if you are shopping.
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Enter panel specs
Type the advertised diagonal in inches, then the horizontal and vertical native pixel counts. Use the lit panel size from the manufacturer — measuring the outer plastic frame overstates size and understates PPI. See also: resolution checker .
Tip Spec sheets list diagonal and resolution; ignore bezel width
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Read PPI and dimensions
The preview and result cards update as you type. Check PPI for sharpness comparisons, then physical width and height for desk fit. Area shows how much surface the panel occupies. See also: calculator tips .
Tip Same diagonal + higher resolution = higher PPI
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Compare common sizes
Use Common Sizes presets for 24″ FHD, 27″ QHD, 27″/32″ 4K, ultrawide, and 15.6″ laptop. Unit Converter shows the same physical size in inches and centimeters. See also: aspect ratio calculator .
Tip Ultrawide width grows faster than diagonal suggests
Common size & density reference
24″ Full HD (~92 PPI)
Office baseline. Sharp enough for spreadsheets and browsing at 100% scaling; gaming panels often start here.
27″ QHD (~109 PPI)
Popular productivity and gaming compromise. Noticeably denser than 27″ FHD without aggressive OS scaling.
27″ 4K (~163 PPI)
Very sharp text; many people run 125–150% scaling. Ideal for photo/video work if GPU bandwidth allows.
34″ ultrawide (~110 PPI at 3440×1440)
Same-ish density as 27″ QHD but much more horizontal workspace — verify desk width before you buy.
When screen size math matters
Buying a monitor
- Compare PPI at the same diagonal before choosing FHD vs QHD vs 4K.
- Check physical width for dual-monitor or ultrawide setups.
- Recalculate seller claims that mix diagonal and resolution.
Desk & mount planning
- Arm VESA capacity cares about weight; clearance cares about width/height.
- Ultrawide stretch is easy to underestimate from diagonal alone.
- Laptop diagonals hide thick bezels — use panel size, not chassis size.
Sharpness & scaling
- Higher PPI needs sensible OS scaling for readable UI chrome.
- Low PPI on a large panel makes text look soft even at native resolution.
- Pair this tool with the Resolution Checker for live DPR.
Phones & tablets
- Enter the published diagonal (for example 6.7 in) with native pixels.
- Browsers cannot read a trusted physical size automatically.
- Used listings often inflate diagonal — verify against the box spec.
Screen size calculator FAQs
What is a good PPI for a monitor?
Around 90–110 PPI is common for 27-inch QHD productivity. 4K at 27 inches often exceeds 160 PPI and may need 125–150% OS scaling. Preference and viewing distance matter more than a single target.
Does PPI include the bezel?
No. Use the active panel diagonal from the spec sheet. Measuring the outer plastic frame overstates size and understates PPI.
Why doesn’t my phone report inches automatically?
Web pages cannot read a trusted physical diagonal from the browser. Enter the published size (for example 6.7 in) with the native pixel resolution for accurate PPI.
Is this the same as the resolution checker?
No. Resolution Checker reads live screen and viewport metrics. Screen Size Calculator needs your diagonal input to derive physical size and PPI.
How do I convert screen size to centimeters?
One inch equals 2.54 cm. The Unit Converter card shows physical width and height in both inches and centimeters after you enter diagonal and resolution.
Why is ultrawide wider than a 27″ 16:9 at the same diagonal?
Diagonal is a corner-to-corner length. A wider aspect ratio spreads that length horizontally, so physical width grows even when the diagonal number matches a shorter 16:9 panel.
Screen size calculator tips
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Use panel diagonal
Enter the lit image area size from the spec sheet — not the outer plastic frame.
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Native resolution only
PPI math assumes the panel’s native pixel grid, not a scaled or cropped mode.
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Check OS scaling next
High-PPI 4K often needs 125–150% scaling in Windows Display settings.
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Retina vs PPI
macOS “Looks like” modes change logical size; this calculator still needs physical diagonal + native pixels.
