Choose the source image
Use the highest-resolution original available. Screenshots and images copied from messaging apps may have fewer pixels than expected.
Pixels → paper → real life
Print the size you actually mean.
Place an image at an exact width in millimetres, centimetres or inches. See the intended dimensions on an A4 preview, check effective PPI and create a physical-size A4 PDF without uploading the image.
Free · No account · Images stay in your browserExact-size image printer
PNG, JPEG, WebP or GIF, up to 25 MB. Animated GIFs use the first decoded frame.Height follows the original image aspect ratio.Intended printed image size50.0 × 50.0 mm
5.00 × 5.00 cm
1.97 × 1.97 in
5.00 × 5.00 cm
1.97 × 1.97 in
Source—
Effective—
A4 use23.8% × 16.8%
Choose an image. It stays inside this browser tab.
A4 proportional preview
5.00 cm · 50.0 mm · 1.97 in
5.00 cm · 50.0 mm · 1.97 in
The page and image are shown in correct proportion. Screen centimetres are not guaranteed; the labels describe the PDF print dimensions.
Function explained
What the tool actually creates.
An A4 PDF with your image positioned at the physical width you requested.
The browser reads the source pixel dimensions, preserves the aspect ratio and converts your requested size into PDF points. The generated page is 210 × 297 mm. The image is centred, and the optional 100 mm line lets you verify whether the print workflow added scaling.
This is different from claiming that the image looks five centimetres wide on your phone or monitor. Screens use different densities and zoom settings. Actual Size Lab treats the on-screen page as a proportional diagram and uses the downloadable PDF as the physical-size instruction.
The source file is not intentionally sent to an application server. Image decoding, resizing and PDF construction occur in the current browser tab. For a complete explanation, read the methodology and limitations.
How to use it
From image to measured print.
Enter the desired printed width
Select millimetres, centimetres or inches. The height is calculated from the source aspect ratio so the image is not stretched.
Review size, fit and effective PPI
Check the three-unit size summary. A warning appears if the image exceeds A4 or enters the 10 mm margin guide. Effective PPI estimates available source detail.
Create the A4 PDF
Keep the 100 mm verification line enabled for the first test. The PDF is generated locally and downloaded by the browser.
Print without automatic scaling
Select A4 and use Actual size, 100%, or No scaling. Disable Fit to page, Shrink and borderless enlargement unless intentionally needed.
Measure the first print
The optional line should measure 100 mm. If it does not, the print application, driver or printer changed the scale. Correct that before relying on the image dimensions.
Practical tips
Avoid the common size traps.
Prefer the original file
Social apps often recompress images. A larger source gives the printer more real detail at the same physical size.
Do not confuse image PPI with printer DPI
Source pixels per printed inch describe image sampling. A printer's advertised dot resolution describes ink or toner placement and is not a one-to-one source-image requirement.
Watch non-printable margins
Many printers cannot place ink to the paper edge. The dashed 10 mm guide is conservative guidance, not a guarantee for every device.
Borderless mode may enlarge
Borderless printing commonly oversprays and may enlarge the page slightly so no white edge remains. That is useful for photos but harmful to exact scale.
Use PDF, then print at 100%
The PDF has an A4 physical page. Opening it in a proper PDF viewer and disabling scaling is more predictable than printing a standalone image from a gallery app.
Verify critical output physically
Software calculations cannot control paper feed, driver behaviour or hardware tolerance. A ruler test is the final check.
Related tools and original guides
Pixels and PPI → print sizeConvert a source pixel dimension into inches, centimetres and millimetres.Print size → required pixelsCalculate the source pixels needed for a requested size and sampling target.Exact-size printing checklistA detailed PDF and printer-dialog workflow for Windows and macOS.DPI, PPI and resolutionA practical explanation of the terms people mix together.A4 pixel dimensionsReference values from 72 to 600 PPI, with formulas and use cases.Why printers change sizeFit, shrink, margins, borderless expansion and driver behaviour.
Frequently asked questions
What to know before you print.
Does the image upload to a server?
No. The selected image is decoded with browser APIs and remains in the current browser tab. The site has no image-upload endpoint. Refreshing or closing the tab clears the working image.
Why does the preview not look physically correct on my screen?
A monitor is not a calibrated ruler. Browser zoom, operating-system scaling and display pixel density vary. The preview is proportional to A4 and the labels describe the intended printed dimensions.
Why is PDF the main download instead of PNG?
A PDF page carries an explicit physical page size. This tool creates an A4 page and places the image using PDF point units, which gives the print dialog a clearer physical-size instruction than a standalone bitmap.
Which print setting should I use?
Select A4 paper and Actual size, 100%, or No scaling. Disable Fit, Shrink oversized pages and borderless expansion unless you understand the scaling they apply.
What is effective PPI?
It is the source image pixel width divided by the requested print width in inches. It estimates how many source pixels are available per printed inch. Printer marketing DPI is a different specification.
Is 300 PPI always required?
No. Around 300 PPI is a common target for close-viewed photo prints, but acceptable resolution depends on subject detail, viewing distance, paper, printer and personal tolerance. The tool reports the number instead of promising a universal quality threshold.
Can I print a passport or official ID photo with this?
You can place an image at a chosen physical size, but official photo rules also cover head size, background, framing, recency and other requirements. Verify the current rules of the issuing authority.
Why might the final print still be slightly wrong?
Printer drivers, non-printable margins, paper feed, borderless enlargement and application scaling can alter size. Use the optional 100 mm verification line and measure the first test print.
Can the tool print larger than A4?
This release creates one A4 PDF page. Sizes larger than 210 × 297 mm are blocked. Poster tiling is not included yet.
Does Actual Size Lab guarantee engineering accuracy?
No. It is a practical print utility, not a calibrated metrology instrument. Do not use it as the sole method for medical, legal, manufacturing or safety-critical tolerances.
Transparency
Useful, but not a measuring instrument.
Actual Size Lab calculates an intended PDF placement. It cannot guarantee the physical behaviour of every printer, driver, paper path or borderless mode.
The formulas, assumptions, browser processing model and known limits are published on the methodology page. The project identity is explained on About, and contact, privacy and terms pages are available from every page.