Resolution to PPI Converter

Q: How to calculate PPI from resolution?

Use PPI = sqrt(width_px^2 + height_px^2) / diagonal_in. Example: 1920×1080 at 24 inches is about 92 PPI.

Q: How to calculate PPI from resolution and screen size?

If you know the diagonal, use PPI = sqrt(width_px^2 + height_px^2) / diagonal_in. If you know the physical sides, use PPI = width_px / width_in = height_px / height_in.

Q: What is 4K resolution in PPI?

It depends on diagonal size. For 3840×2160 (4K), 27 inches is about 163 PPI and 32 inches is about 138 PPI.

Q: What is a good PPI for mobile?

Around 300 PPI and above is considered crisp for phones; many modern models are between 400 and 500+ PPI.

Q: Is 300 PPI enough for print?

Yes, 300 PPI is a common high-quality print standard. Large posters that are viewed from a distance can be acceptable at 150–200 PPI.

Q: 300 PPI to resolution (common sizes)

4×6 inches = 1200×1800 pixels, 5×7 = 1500×2100, 8×10 = 2400×3000, Letter (8.5×11) = 2550×3300, A4 (8.27×11.69) = 2480×3508 at 300 PPI.

Q: Resolution to PPI converter online — how do I use it?

Enter width×height in pixels and the screen diagonal in inches (or physical width/height). The tool returns PPI along with px/mm and px/cm. You can copy or share the result URL.

Convert resolution to PPI online. Enter width×height (pixels) and screen size to get pixel density, plus px/mm, examples (1080p/1440p/4K), mobile guidance, and a 300 PPI resolution chart.

Resolution to DPI ⇌ Resolution to PPI

How to use the Resolution → PPI calculator

Enter your pixel resolution and a physical screen size to compute PPI. You’ll also get unit helpers (px/mm, px/cm) and a diagonal-pixels check, plus quick actions to Copy or Share the result URL.

How to use the Resolution → PPI calculator

1920×1080
2560×1440
3840×2160 (4K)
5120×2880 (5K)
1280×720

13.3″
14″
15.6″
24″
27″
32″

Inputs

Resolution — Width (px) & Height (px).
Screen size — primary: Diagonal (in) with an in/cm toggle.
Optional: Physical Width & Height in in/cm.
When provided: PPI = width_px / width_in = height_px / height_in.

Outputs

PPI (two decimals).
px/mm = PPI ÷ 25.4 • px/cm = PPI ÷ 2.54.
Diagonal pixels = √(width_px² + height_px²) — for quick verification.

px/mm = PPI / 25.4 • mm/px = 25.4 / PPI

Actions

Copy the result or Share link (URL with parameters).
Need print output? → 300 PPI → resolution chart
PPI calculator (have diagonal only?)
DPI calculator • DPI ↔ PPI

Formula & how it works

Compute PPI from resolution and size using the diagonal, or directly from the physical width/height if you know them.

Core (using diagonal):
  PPI = sqrt( width_px^2 + height_px^2 ) / diagonal_in

If physical width/height are known:
  PPI = width_px / width_in  =  height_px / height_in

Helpers:
  px_per_mm = PPI / 25.4
  mm_per_px = 25.4 / PPI

Note: Resolution ≠ physical size. The same 1920×1080 image can be ~92 PPI at 24″ or ~82 PPI at 27″. You must supply a real measurement (diagonal or width/height) to get a correct PPI.

Quick examples — convert resolution to PPI

Fast lookups you can compare with the resolution to PPI calculator. Use them to sanity-check inputs before you convert resolution to PPI.

Monitors

1920×1080 @ 24″ → ≈ 92 PPI
1920×1080 @ 27″ → ≈ 82 PPI
2560×1440 @ 27″ → ≈ 109 PPI
3840×2160 (4K) @ 27″ → ≈ 163 PPI
3840×2160 (4K) @ 32″ → ≈ 138 PPI

Phones

6.1″ @ 2532×1170 → ≈ 457 PPI
6.7″ @ 3088×1440 → ≈ 509 PPI

resolution to ppi chart

Quick lookup for common resolutions and diagonals. Values are approximate (≃).

Desktop & laptop

Resolution	13.3″	24″	27″	32″
HD (1280×720)	≃ 110.4	≃ 61.2	≃ 54.4	≃ 45.9
FHD (1920×1080)	≃ 165.6	≃ 91.8	≃ 81.6	≃ 68.8
QHD (2560×1440)	≃ 220.8	≃ 122.4	≃ 108.8	≃ 91.8
4K (3840×2160)	≃ 331.3	≃ 183.6	≃ 163.2	≃ 137.7
5K (5120×2880)	≃ 441.7	≃ 244.8	≃ 217.6	≃ 183.6

Mobile

Resolution	5.8″	6.1″	6.7″
2340×1080	≃ 444.3	≃ 422.5	≃ 384.7
2532×1170	≃ 480.9	≃ 457.3	≃ 416.3
3088×1440	≃ 587.5	≃ 558.6	≃ 508.5

Looking for more? Try our resolution to PPI chart for 4K resolution and beyond.

300 PPI Resolution Image — Pixels Needed

For high-quality print at 300 PPI (often called 300 DPI), use the rule:

pixels_needed = inches × 300   (apply to width and height)

Print size	Inches	Pixels @ 300 PPI
4 × 6	4″ × 6″	1200 × 1800
5 × 7	5″ × 7″	1500 × 2100
8 × 10	8″ × 10″	2400 × 3000
Letter	8.5″ × 11″	2550 × 3300
A4	8.27″ × 11.69″	2480 × 3508

Tip: “300 PPI resolution image” and “300 DPI” are used interchangeably for print sizing. For other PPIs, use the 300 ppi to resolution helper or the main calculator.

Mobile Guidance — How much PPI is good for mobile?

Quick rule of thumb: ≥300 PPI is considered very good for smartphones.
400–500+ PPI is extremely sharp, especially at close viewing distances.
The perceived sharpness depends on both viewing distance and the panel type.

~300 PPI = Great
400–450 PPI = Ultra sharp
500+ PPI = Extremely high density

Why it varies

Viewing distance: The closer you hold the phone, the more PPI matters.
Panel & sub-pixel layout: OLED vs IPS and pixel arrangement (RGB vs PenTile) affect perceived sharpness.
System resolution vs PPI: Don’t confuse software resolution settings with physical pixel density — screen diagonal size is what sets PPI.

FAQs — Resolution to PPI

How to calculate PPI from resolution?

PPI = sqrt(width_px² + height_px²) ÷ diagonal_in. Example: 1920×1080 at 24″ ≈ 92 PPI.

How to calculate PPI from resolution and screen size?

Use the diagonal formula above, or (if you know the physical sides): PPI = width_px ÷ width_in = height_px ÷ height_in.

What is 4K resolution in PPI?

It depends on diagonal size. 3840×2160 (4K) at 27″ ≈ 163 PPI; at 32″ ≈ 138 PPI.

What is a good PPI for mobile?

Generally ≥ 300 PPI looks crisp at normal viewing distances; many modern phones are 400–500+ PPI.

Is 300 PPI enough for print?

Yes for most quality prints. Large posters viewed from farther away can be acceptable at 150–200 PPI.

300 PPI to resolution (common sizes)

4×6 → 1200×1800, 5×7 → 1500×2100, 8×10 → 2400×3000, Letter (8.5×11) → 2550×3300, A4 (8.27×11.69) → 2480×3508.

Resolution to PPI converter online — how do I use it?

Enter width×height (pixels), add the diagonal in inches (or physical width/height), then read PPI plus helpers (px/mm, px/cm). Use Copy/Share for quick reuse.

Also see: DPI vs PPI and our PPI calculator.

Related tools

PPI calculator
— reverse when you already know the diagonal (resolution → PPI).
DPI calculator
— printer/scanner DPI from pixels & inches ·
DPI ↔ PPI
Pixels → Inches
— convert pixels to physical inches at any PPI.
Pixels → CM
·
Pixels → MM

Conclusion

PPI is a density measure — it always needs both the pixel resolution (width × height) and a real physical size (diagonal or width/height). Resolution alone can’t determine PPI.

Use the calculator above to convert resolution to PPI instantly and grab helpful unit factors for print and screen work.

External reference:
Wikipedia — Pixel density
·
Wikipedia — Image resolution