I know the paper format
Use PaperSize for A-series and common sheet dimensions, then open DpiCalc when you need the pixel dimensions for a selected density.
Print and image sizing
Choose the right tool before you resize or print
Paper dimensions, pixel dimensions and image density describe different parts of one job. This guide connects the focused SympifyApps tools that calculate the numbers, prepare a local file and keep the original product pages exactly where they are.
Browser-local file processingOne clear job per toolNo account required
Start from what you know
Match the question to the calculator
The shortest route depends on which value is fixed: the sheet, the source pixels, the screen or the file you need to change.
I know the image pixels
Use DpiCalc to convert width and height into inches or centimetres at an explicit PPI, or work backwards from a target print size.
I know the screen size
Use ScreenPPI with resolution and diagonal size. Screen density is a display measurement and should not be silently substituted for print density.
I need to change the file
Calculate first, then use ImageResize, ImageCompress or VectorPNG for the bounded browser-local transformation you actually need.
Four values, four meanings
Keep physical size, pixels and density separate
Most wrong answers begin by treating two different measurements as if they were interchangeable.
- Physical size
- Millimetres, centimetres and inches describe the intended sheet or printed result. A4 remains 210 × 297 mm regardless of the pixel density chosen for a raster image.
- Pixel dimensions
- Width × height in pixels describes the raster grid actually stored in an image. Changing only a density tag does not create additional source detail.
- PPI or DPI
- PPI is pixels per printed inch; DPI is often used informally in the same calculator searches. The calculation needs one explicit density value rather than an assumed default.
- Aspect ratio
- The width-to-height relationship determines whether content fits a target rectangle without cropping or distortion. It does not specify physical size or resolution by itself.
Focused collection
Seven tools for one complete sizing workflow
Open only the step you need. Every destination keeps its own canonical URL and remains independently usable.
Paper reference
PaperSize
Look up named paper dimensions and compare formats before calculating any raster size.
Print calculation
DpiCalc
Convert pixels, print dimensions and an explicit PPI value in either direction.
Display calculation
ScreenPPI
Calculate screen pixel density from resolution and physical diagonal without mixing it with print size.
Shape comparison
AspectFit
Compare source and target aspect ratios to understand fit, crop and letterbox geometry.
Local resize
ImageResize
Resize one supported image to explicit pixel dimensions entirely inside the browser.
Local compression
ImageCompress
Compress one JPEG, PNG or WebP after the dimensions are settled, with visible output evidence.
Vector export
VectorPNG
Render a restricted local SVG into a PNG at explicit output dimensions without uploading it.
Practical order
A repeatable four-step workflow
- 1
Define the intended output
Record the paper or physical dimensions, orientation and any requirements supplied by the destination that will receive the file.
- 2
Calculate before editing
Use the relevant paper, density or aspect-ratio tool and keep the exact result visible while preparing the file.
- 3
Make one deliberate transformation
Resize, compress or rasterize only when necessary. Keep the source file so the operation remains reversible.
- 4
Verify the exported evidence
Check the final pixel dimensions, file type and byte size, then compare them with the requirements of the service or workflow you are using.
Common questions
Paper size and pixel density basics
Are DPI and PPI the same thing?
Not strictly. PPI describes image pixels per physical inch, while printer DPI describes output dots. Many searches and applications use DPI when they mean a target raster PPI, so SympifyApps makes the entered value explicit.
Can pixels be converted to centimetres without PPI?
No unique physical size follows from pixels alone. The same pixel width can occupy different centimetre widths depending on the selected pixels-per-inch value.
Does changing image DPI metadata add detail?
Changing a density tag alone does not add source pixels. A resampling operation can create a new raster grid, but it cannot restore detail that was absent from the source.
Do file tools upload my images?
The linked ImageResize, ImageCompress and VectorPNG workflows process supported files inside the browser. Their product pages state exact limits and network policies before you select a file.
Need a different task?
Browse every focused SympifyApps product
Search the complete catalog by outcome or open another category without changing this guide.