OMR Checker
Grade OMR answer sheets with your phone camera, a scanner or a PDF. Enter the answer key once, add the filled sheets, and get scores, section-wise marks and a CSV report. Everything stays on your device.
Sheet layout
No layout yet. It's read automatically from the QR code on the first sheet you add, or choose one below.
Marking scheme
| Section | Qs | Correct | Wrong |
|---|
Answer key
Set the sheet layout first, then enter the correct answers.
Tip: print an answer-key page from the generator, or fill in a blank sheet with the correct answers and add it below. Answer-key pages are recognised automatically.
Add answer sheets
Drop photos, scans or PDFs here
JPG, PNG, WebP or multi-page PDF. Add as many as you like.
Results
- Sheets
- 0
- Average
- –
- Highest
- –
- Lowest
- –
| # | Roll no. | Set | Score | % | Right | Wrong | Blank | Status | File | Actions |
|---|
Checked sheets will appear here.
- No OMR machine needed
- Negative marking
- CSV export
- Photos stay on your device
How it works
Check a whole class in minutes
The checker works with sheets made by the ToolAdda OMR sheet generator.
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Enter the answer key
Click the correct option for each question, paste the key as text, or scan a filled answer-key page. Set marks per section, including negative marking.
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Photograph or scan the sheets
Use the live camera, upload phone photos, or add a multi-page PDF from a scanner. The QR code tells the checker which layout each sheet uses.
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Review and export
See each student's roll number, set and score, open any sheet to verify the marks, correct a reading if needed, and download a CSV.
How the OMR checker reads a sheet
- Finds the four black corner squares. They mark the exact frame of the printed sheet, even if the photo is tilted, rotated or taken at an angle.
- Reads the QR code to learn the layout: number of questions, options, sections, roll number digits and the page number.
- Straightens the image with a perspective transform, so every bubble can be located precisely.
- Measures how dark each bubble is compared with the paper right around it, which copes with shadows and uneven light.
- Decides which bubbles are filled using a threshold calculated for that sheet, and flags blank and multiple answers.
Tips for accurate results
- Lay the sheet flat on a darker surface, in even light, and avoid your own shadow.
- Fit the whole sheet in the photo with all four corner squares visible and a little space around them.
- Hold the phone steady and roughly parallel to the page. Moderate tilts are corrected automatically.
- Scanners work great. Scan at 150–300 DPI in greyscale and upload the PDF directly.
- Review flagged sheets. Sheets marked "Check" have multiple marks, an unreadable roll number or a missing set code.
Accuracy and responsibility
The checker is designed to read clearly filled bubbles reliably, but no automatic system is perfect. Light pencil marks, stray ink, folds and very blurry photos can affect the result. For high-stakes exams, review flagged sheets and spot-check a few results before publishing marks.
FAQ
OMR checker questions
Can I check OMR sheets with a mobile phone?
Yes. Open this page on your phone and tap Use camera. When all four corner squares are in view, the sheet is captured and graded automatically. You can also upload photos taken with the camera app.
Does it work with any OMR sheet?
It works with sheets created by the ToolAdda OMR sheet generator, because it relies on their corner squares and QR code. Sheets from other sources have different layouts and can't be read.
How does negative marking work?
Set marks for correct and wrong answers per section in step 1, for example 4 and −1. Blank answers score zero. You can choose whether multiple marks on one question count as wrong or as blank.
Can students have different question paper sets?
Yes. If the sheet has a booklet set code, enter a key for each set. The checker reads the set each student filled in and uses the matching key.
What if a mark is read incorrectly?
Open the sheet from the results table. The photo shows what was detected, and you can change any response. The score updates immediately.
Are the photos uploaded to a server?
No. Photos, PDFs, answer keys and results are processed in your browser and never leave your device. Closing the page clears the photos; your answer keys and marking scheme are remembered on this device.
How many sheets can I check at once?
There is no fixed limit. Each sheet takes a fraction of a second on a modern phone or computer, so a class of 60 is done in about a minute.