LensUp — Free Online Document Scanner

免费浏览器内文档扫描：照片转清晰PDF。支持裁剪、透视校正、可选水印或签名添加及压缩。无需上传或注册。

文档

A phone photo,
returned as a clean sheet.

Crop, adjust contrast, and straighten by hand when you need to — then export a printable A4 PDF, or compress toward the size a form asks for. Files never leave your device.

Take a photo or choose files All tools Feedback

No upload· on-deviceFree· no watermark14 languages

This browser can’t open PDFs — it’s too old to run the PDF engine. Use the latest Chrome, Edge, Firefox or Safari, or a newer phone or computer.

Copy linkCopying was blocked — the link below is selected; copy it manually.

1Add

Take photo or choose image/PDF

On a computer, drag images or PDFs here, or paste a screenshot (Ctrl / ⌘ + V).

Stays on this device

Couldn’t load part of this page — check your connection and try againRestoreClearTry again

2Adjust

Effect

White documentGrayscaleColorBlack & whiteDe-shadowFade colored penScanned look

White document — Whitens the paper background; dark print stays dark.

Grayscale — Removes the color and adds a little contrast.

Color — Keeps the original colors, with no tone change.

Black & white — Pushes ink to black and paper to white; some gray can remain.

De-shadow — Evens out shadows and uneven light; keeps colored ink and stamps.

Fade colored pen — Fades blue, red and green ink; cannot reliably remove black handwriting.

Scanned look — Warm gray paper, fine grain and a slight tilt; colored ink turns gray.

ID card · A4

Back85.6 × 54 mm

Swap front and back

3Export

Export optionsA4 · Single · No limit

Paper size

A4LetterOriginal

Layout

Single2-up4-upID card

ID card: places the first two pages as front & back at ID-1 size on one A4 sheet. Use Edit to crop or align the four corners.

Output format

AutoPDFJPGPNG

PNG is lossless, so target sizes do not apply.

Compress to

No limit200 KB500 KB1 MB

High detail

Uses original photos. Larger files and slower export. Available with No limit or PNG.

Physical output size

Width Heightmm

Optional. Keeps the image ratio and never exceeds the page.

WatermarkOff

Watermark textWatermark image

An image takes priority when text and image are both set.

Opacity30%Size8%Rotation45°

Repeat watermarkClear

Signature / stampOff

Signature or stamp image

A transparent PNG gives the cleanest result.

Opacity100%Size22%

Position Top left Top right Bottom left Bottom right Center

All pagesPage

Clear

Export PDF

PrintShare

Drop to add

Page edges not found — check the cornersExport PDF

All tools in one place

Every tool opens focused, with the same crop-mark editor. Nothing is uploaded.

How to scan a document to PDF

Photograph it, crop and straighten, choose a scan effect, then export — you get a clean scanned PDF, no hardware needed.

1 ### Capture: photograph the document

Photograph any paper document or add images — multiple pages merge into one PDF in order.
2 ### Refine the scan in your browser

Crop, straighten, fix perspective, and pick a scan effect — right in your browser.
3 ### Export a printable scanned PDF

Save a clean, printable scanned PDF, or compress it toward an upload limit.

Made for real documents

Crop, adjust contrast, and straighten by hand when you need to — then export a printable A4 PDF, or compress toward the size a form asks for. Files never leave your device.

Real-scan quality

De-shadow, perspective correction and document whitening turn a phone photograph into a proper scan — a real document scanner, no hardware needed.
Built for upload limits

Aim for an upload limit such as 200 KB, or lay out 2-up and ID-card copies for printing.
Yours, private

Every file-processing step runs in your browser — no upload of your files and no account needed.
Free, everywhere

Unlimited, no watermark, works on phone, tablet and computer, in your language.

Who uses LensUp?

Government and job applications

Need to compress an image to 200 KB for an application portal? LensUp works toward that upload limit and warns you when the target cannot be reached.
Students and teachers

Scan worksheets, straighten photographed pages, and fade colored pen marks while keeping dark printed text visible.
ID and paperwork errands

Make an ID card copy with the front and back on one A4 page at ID-1 size. Use Edit to crop or align each side manually.
Receipts and records

Photograph receipts or paper records, arrange the pages, and merge them into one PDF in the order you choose.

Sources and technical references

These standards and browser references support the file-handling, image-processing and ID-card format statements above.

W3C File API

Defines how a web application can access files that a person explicitly selects.
MDN Canvas API

Documents browser-side drawing and photo manipulation used for local scan effects.
ISO/IEC 7810:2019

Defines physical characteristics for identification-card formats, including the ID-1 format used by the copy layout.

Document scanner FAQ

How do I scan a document to PDF without a scanner?

Photograph it, crop and straighten, choose a scan effect, then export — you get a clean scanned PDF, no hardware needed.

Is it really free and private?

Yes. Unlimited, no watermark, no sign-up, and every step runs locally in your browser — files are never uploaded.

Can I compress a PDF to 200 KB or another upload limit?

Choose a target such as 200 KB or 500 KB. LensUp tries to stay below it, but extreme targets may still return the smallest possible file with a warning.

How do I scan a document to PDF without an app?

Photograph the page or choose an image, crop and straighten it, pick a scan effect, then export a scanned PDF. Everything runs in your browser, with no app or upload.

How do I remove the shadow from a document photo?

Use De-shadow to remove shadow from the scan and even out the lighting, then use Edit to crop or correct perspective. Everything stays in your browser.

Open the de-shadow tool

Can I scan an ID card front and back onto one page?

Choose the ID card layout to place the first two pages as front and back at ID-1 size on one A4 sheet. Use Edit to crop or align the four corners manually.

Open the ID card copy tool

Cancel

EditCrop

Done

Drag the corners to select the area to keep

Original page shape Unknown A4 Letter ID-1 Custom ratio Portrait Landscape:Use positive values with a ratio between 1:20 and 20:1.

⌗Crop◇Perspective

↶Rotate left↷Rotate right↩Undo↺Reset◉Compare

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Every message goes straight to the team.

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LensUp — Free Online Document Scanner

文档

A phone photo,returned as a clean sheet.

1Add

2Adjust

3Export

Popular tools

All tools in one place

Scan & clean

Size & convert

ID & forms

From our studio

How to scan a document to PDF

Made for real documents

Real-scan quality

Built for upload limits

Yours, private

Free, everywhere

Who uses LensUp?

Government and job applications

Students and teachers

ID and paperwork errands

Receipts and records

Sources and technical references

Document scanner FAQ

Send feedback

Thank you!

A phone photo,
returned as a clean sheet.