Upscale image pixels locally by multiplier or print target, then sharpen existing edges and check effective DPI before poster layout.
Choose 2x, 3x, 4x, or an A-series target. The generated file uses high-quality browser resampling, optional edge sharpening, and exact output readings before you download or continue.
JPG, PNG, or WebP
Your source stays on this device. Canvas decodes, enlarges, sharpens, and exports locally; the file enters IndexedDB only if you choose Use in Rasterbator.
Multiplier, print target, sharpening, and format
Targets use A4 210 × 297 mm, A3 297 × 420 mm, and A2 420 × 594 mm. Each preset follows the source orientation and fills that exact rounded pixel rectangle.
The preview helps you check framing, edge behavior, transparency, and obvious resampling artifacts. It is not proof that enlargement recovered information that was missing from the original file.
A browser scales both previews to fit these cards, so judge the numeric output size and effective DPI separately. For print decisions, those readings are more dependable than apparent sharpness on a small screen.
More pixels are useful only when they answer a print question. This page connects enlargement to paper targets, effective DPI, and a local poster handoff instead of treating 4x as an automatic quality guarantee.
A multiplier is useful when you already know how much larger the source should become. An 800 × 600 file at 2x becomes exactly 1600 × 1200, while 3x and 4x produce 2400 × 1800 and 3200 × 2400.
Print targets answer a different question. A2 landscape at 150 DPI is 3508 × 2480 px, so the button gives you that exact rounded canvas without asking you to convert millimeters yourself.
The enlarge pass uses one high-quality draw into the final output canvas. After that, the sharpen control can increase contrast around existing neighboring pixels, which may make type, line art, or clear subject boundaries look firmer.
At sharpen 0, the edge pass is skipped completely. The output is the untouched resampled canvas, so there is no hidden filter changing pixels when the control says zero.
Effective DPI connects output pixels to a physical paper width. The summary shows approximate A3 and A2 landscape DPI using the generated width, so you can see whether the enlargement moves your file toward a practical print density.
DPI is not a universal quality score. Large wall posters are usually viewed farther away than a hand-held print, so a lower effective DPI can still look appropriate when the image, viewing distance, and printing method support it.
The workflow stays simple: open the real source, choose a meaningful output target, then keep the generated file or continue to the poster maker.
Start with a supported photo file from your device. The browser reads its real pixel dimensions locally, which gives every multiplier, preset, file-size reading, and DPI calculation a concrete starting point.
Begin with the highest-quality source you actually have. Heavy compression, blur, tiny text, and lost texture remain limitations after enlargement because extra output pixels do not restore uncaptured scene information.
Use 2x, 3x, or 4x when the scale itself is your requirement. The tool blocks multiplier outputs above 32,768 pixels on either side or 120 million total pixels before Canvas allocation.
Use A4, A3, or A2 at 150 or 300 DPI when paper is the requirement. The source orientation decides portrait or landscape, then the preset fills that exact target rectangle.
Check output dimensions, factor, actual Blob size, effective DPI, and format before saving. PNG preserves transparency; JPG uses 90% quality and flattens transparent areas onto white for a predictable photo-style export.
Download uses a descriptive filename containing the final dimensions. That makes it easier to distinguish several test enlargements when you compare 2x, 4x, or a paper-target version outside the browser.
