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PPI to DPI Calculator

Find your screen's pixel density (PPI) from resolution and screen size, check the DPI a print will actually achieve, or work out the pixel resolution you need for a target print size — plus a device PPI reference table and viewing-distance tools, all with instant results.

Phone avg. ~460 PPI Monitor avg. ~110 PPI Photo print 300 DPI Updated: Jul 19, 2026
The screen's physical corner-to-corner length, in inches.
Quick pick a device:
Start typing to filter — click a result to fill in its resolution and diagonal.
Pick a quick print size:
Find the pixel resolution you need for a target DPI and print size:
Quick pick a target DPI:
Compare the pixel density of two screens side by side — great for choosing between two phones, monitors, or TVs:
Screen A
Quick pick:
Screen B
Quick pick:
Quick answer PPI (pixels per inch) measures a screen's pixel density: PPI = √(width² + height²) ÷ diagonal(in). DPI is the number of dots per inch a printer lays down; print quality typically reaches photo standard at 300 DPI. The calculator above instantly finds your screen's PPI, the DPI a print will achieve, and the pixel resolution you need for a target print size.
72–96Web/screen PPI standard
150–200Poster print DPI range
300Photo/magazine print DPI
300+Retina quality threshold (phone)
⚙️ Note: PPI is calculated with PPI = √(width² + height²) ÷ diagonal(in), which assumes the screen's actual pixels are square (true for the vast majority of modern displays). The Print DPI calculation scales the image's pixel size against your chosen physical print size. Quality badges (Poor→Excellent) are based on widely used practical thresholds; the actual result can vary by screen/print type, viewing distance, and paper.
▦ PPI to DPI Calculator — ToolPico ↗

What is PPI and DPI, and how do you calculate them?

A complete guide — with formulas and examples — to screen pixel density, print resolution, and the difference between the two.

PPI (Pixels Per Inch) measures how many pixels are packed into every inch of a digital screen's diagonal, and it determines how sharp that screen looks. DPI (Dots Per Inch) is the density of ink dots a printer can lay down on paper. Both work on a "per inch" basis, but one is for screens (pixels) and the other for print (dots) — in everyday use, the two terms get used interchangeably all the time. The calculator above handles both directions, plus the reverse calculation of pixels needed for a target print size, instantly and with an explanation.

How is screen PPI calculated?

Quick answerFirst, the Pythagorean theorem gives the total number of pixels along the screen's diagonal: √(width² + height²). That number is then divided by the screen's physical diagonal length in inches: PPI = √(width² + height²) ÷ diagonal(in). For example, a 24-inch monitor at 1920×1080 has a PPI of about 91.79.

How many DPI do you need for printing?

Quick answer300 DPI is the standard for photo and magazine-quality printing. 150–200 DPI is usually enough for posters and large prints viewed from a distance; for giant prints viewed from very far away, like billboards, even 20–50 DPI is acceptable. For screen/web display, 72–96 DPI is standard.
  • 300 DPI+ — photo prints, business cards, magazines (viewed up close).
  • 150–200 DPI — large posters, banners (medium-to-far viewing distance).
  • 72–96 DPI — web pages, screenshots (a pixel is treated as equal to a dot).
  • 20–50 DPI — billboards, building wraps, and other giant prints viewed from very far away.

What does 300 DPI mean, and why is it the standard?

Quick answer300 DPI means a print contains 300×300 dots within every square inch. At that density, the human eye can't pick out individual dots from a normal reading distance (about 10–12 inches), so the print looks smooth and photo-quality. That's why photo labs and print shops default to 300 DPI.

How do you calculate photo print resolution?

Quick answerPixels needed = print size(in) × target DPI. For example, a 4×6 inch photo at 300 DPI needs about 1,200×1,800 pixels. If your image is lower-resolution than that, the print may come out blurry or pixelated — the "Print DPI" tab above calculates this automatically.

Retina displays and the pixel-density quality scale

As pixel density rises, text and images look sharper. The widely used practical scale is: below 100 PPI is Poor, 100–150 is Fair, 150–200 is Good, 200–300 is Very good, and 300 PPI and above is Excellent (Retina). This threshold is a practical rule of thumb based on typical eye-to-screen distance, not an absolute law of physics — a TV is viewed from much farther away than a monitor, so it can look sharp at a lower PPI.

How many PPI do common devices have?

Reference PPI values for frequently searched device-resolution combinations (static reference — check the manufacturer's current specs for exact figures).

Example device PPI values
Device / resolutionDiagonalPPI
iPhone 15 Pro Max (1290×2796)6.7"460
Samsung Galaxy S24 Ultra (1440×3120)6.8"505
iPad Pro 11" (1668×2388)11"264
Full HD monitor (1920×1080)24"92
4K UHD monitor (3840×2160)27"163
MacBook Pro 14" (3024×1964)14.2"254
55" 4K TV (3840×2160)55"80

Popular calculations

Related mini calculators: viewing distance & camera print size

Instantly calculate the ideal viewing distance from a screen's PPI, whether you'll see pixels from a distance you specify (PPD / Retina check), or the maximum print size from your camera's megapixels.

👁️Optimal viewing distance
The average eye can't resolve detail smaller than about 1 arc-minute. This gives the distance at which pixels become invisible.
📷Max print size from camera MP
Find the largest size you can print from your camera's megapixel count at a target DPI.
🔍Am I Retina at this distance?
Enter your own viewing distance to find out whether the screen is "Retina" from there, and its pixels-per-degree (PPD) value.

PPI/DPI reference tables

Citable practical thresholds: typical PPI by device category, DPI needed by print type, and the quality scale.

Typical PPI range by device category
CategoryTypical PPI
Flagship phone420–510
Mid-range phone270–400
Tablet220–330
Laptop140–260
Desktop monitor (FHD/4K)90–165
TV (viewed from a distance)40–90

Static reference table; check your device's manufacturer specs for the exact value.

Recommended DPI by print type
Print typeRecommended DPI
Photo, magazine, business card300
Book interior page, catalog250–300
Poster (near-medium distance)150–200
Roll-up banner100–150
Billboard / building wrap20–50
PPI quality / Retina scale
PPI rangeQuality
0–99Poor
100–149Fair
150–199Good
200–299Very good
300+Excellent (Retina)
Android pixel-density buckets (dpi qualifier → density scale)
BucketPPI rangeDensity scale
LDPI (ldpi)~1200.75x
MDPI (mdpi)~1601x (baseline)
HDPI (hdpi)~2401.5x
XHDPI (xhdpi)~3202x
XXHDPI (xxhdpi)~4803x
XXXHDPI (xxxhdpi)~6404x

Android groups actual screen PPI into these standard "dpi" buckets for scaling app assets (e.g. drawable-xxhdpi). Most current flagship phones fall in the XXHDPI–XXXHDPI range. Enter your device's resolution and diagonal in the "Screen PPI" tab above to see its exact PPI and compare it to this table.

PPI/DPI terms glossary

Short definitions of the core terms used in pixel density and print resolution.

PPIPixels Per Inch — the number of pixels per inch on a screen; measures screen sharpness.
DPIDots Per Inch — the number of dots a printer can lay down per inch.
ResolutionA screen or image's horizontal × vertical pixel count (e.g. 1920×1080).
DiagonalThe physical length from one corner of a screen to the opposite corner, usually measured in inches.
Dot pitch / pixel pitchThe physical distance (mm) between two adjacent pixel centers; it shrinks as PPI rises.
RetinaApple's marketing term for a pixel density high enough that the eye can't pick out individual pixels from a normal viewing distance.
Megapixel (MP)Total pixel count expressed in millions (width × height ÷ 1,000,000).
Aspect ratioThe ratio of width to height (e.g. 16:9, 3:2); defines the shape of an image or screen.

In-depth guides

Detailed answers to the most common PPI/DPI questions.

Why does my phone look sharper than another one? (comparing PPI)

Even if two phones have the same screen size, they'll have different PPI if their resolutions differ. For example, a 6.1-inch screen at 2532×1170 gives about 460 PPI, while the same size at 1600×720 gives only about 263 PPI. On the higher-PPI screen, text edges and thin lines look noticeably smoother.

Enter each phone's resolution and diagonal separately into the "Screen PPI" tab above to compare them — the tool also shows a quality badge (Poor→Excellent) automatically.

Can I print my phone photo as a 12×18 inch poster?

To find out, enter your photo's pixel dimensions (phone cameras typically shoot 3,000–4,000 px wide) and your target print size (12×18 in) into the "Print DPI" tab. The tool calculates the DPI you'll actually get; above 150 DPI is usually fine for poster quality, and above 300 DPI is photo quality.

If you try to print a low-resolution image (say, one downloaded from a messaging app or heavily compressed) at a large size, the resulting DPI will be low and the print may look blurry or pixelated — which is why it's important to use the original, uncompressed file.

What DPI should I design in for print work?

For designs that will only ever be viewed on a screen (web, social media), 72–96 DPI/PPI is enough; going higher just bloats the file size unnecessarily. For anything headed to print — brochures, business cards, packaging — 300 DPI is the standard. Large-format prints (roll-up banners, posters) are viewed from farther away, so around 150 DPI still gives an acceptable result.

The "Required Pixels" tab tells you exactly what pixel size to build your working file at, once you enter your target DPI and print size.

Add this calculator to your site (embed code)

Embed the PPI/DPI calculator on your own website for free. Copy the code below into your HTML — the tool runs in a simplified view and links back to this page as its source.

The embedded tool has a fixed layout; you can adjust the height value to fit your site. No ads or personal data, runs entirely client-side.

Frequently asked questions

What's the difference between PPI and DPI?
PPI (Pixels Per Inch) is the number of pixels packed into each inch of a screen's diagonal, and it measures how sharp a digital display (phone, monitor, TV) looks. DPI (Dots Per Inch) is the density of ink dots a printer can lay down on paper. The correct term for screens is PPI and for print output is DPI; in everyday use the two terms are often used interchangeably.
How do you calculate screen PPI?
First, the Pythagorean theorem gives the total pixel count along the diagonal: √(width² + height²). That number is then divided by the screen's physical diagonal length in inches: PPI = √(width² + height²) ÷ diagonal(in). For example, a 24-inch, 1920×1080 monitor has a PPI of about 91.79.
How many DPI do you need for printing?
The standard for photo and magazine-quality printing is 300 DPI. For posters, 150–200 DPI is usually enough; for giant prints viewed from very far away, like billboards, 20–50 DPI is acceptable. For web/screen display, 72–96 DPI is standard.
What does 300 DPI mean?
300 DPI means a print contains 300×300 dots within every square inch; at this density the human eye can't distinguish individual dots from a normal reading distance (about 10–12 inches), and the print looks photo-quality smooth.
Why does calculating pixel density matter?
Pixel density (PPI) is calculated with PPI = √(width²+height²) ÷ diagonal(in) and shows how tightly packed a screen's pixels are. Higher PPI makes text and images look sharper; 300 PPI and above is generally called "Retina" quality.
How do you calculate photo print resolution?
Pixels needed = print size(in) × target DPI. For example, a 4×6 inch photo at 300 DPI needs about 1,200×1,800 pixels. If your image is lower-resolution than that, the print may look blurry.
What does "Retina display" mean?
Retina is a marketing term for a pixel density high enough that the human eye can't distinguish individual pixels from a normal viewing distance; the generally accepted threshold on phones is ~300 PPI and above. The threshold shifts with viewing distance.
How do you find the pixel resolution needed from a DPI and print size?
Multiply the target DPI by the print size (converted to inches): required width = print width(in) × DPI, required height = print height(in) × DPI. The "Required Pixels" tab converts your inch or cm input automatically and performs this calculation.
Will I see individual pixels on my TV or monitor from a certain distance?
This is determined by the screen's pixels-per-degree (PPD) value at that distance. The human eye can resolve about 1 arc-minute (60 PPD); at 60 PPD or higher individual pixels can't be told apart and the screen looks "Retina" from that distance. The "Am I Retina at this distance?" mini tool above calculates PPD from your resolution, diagonal, and viewing distance (ft/m) and tells you whether you'll see pixels. For example, viewing a 55-inch 4K TV from 10 feet gives a PPD of about 168, so pixels are not visible.
How can I compare the PPI of two screens or devices?
Use the "Compare Screens" tab above: enter the resolution and diagonal size for Screen A and Screen B — or pick them from the searchable device library of 45+ phones, tablets, laptops, monitors, and TVs — and the tool shows both PPI values side by side, including the exact PPI difference and percentage, so you can quickly see which screen is sharper.

Methodology & sources

ToolPico's PPI to DPI Calculator is a free, independent tool. The calculation engine applies the standard Pythagorean PPI formula directly (√(width²+height²) ÷ diagonal); the Print DPI calculation scales the image's pixel size against your target physical print size; and the Required Pixels calculation multiplies the target DPI by the print size to find the pixels needed. Quality/Retina thresholds are based on widely accepted practical references in the display and print industry (72–96 DPI for screens, 300 DPI for photo printing, ~300 PPI for the Retina threshold).

All calculations run in your browser; no data is sent to a server. Last updated: July 19, 2026. The device PPI reference table is static example data; small differences from current manufacturer specs may occur.
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