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About this tool
Check a roll or registration number against length, character-set and prefix rules before you submit a form.
This validator checks a roll or registration number against structural rules — exact length, allowed characters, required prefix and stray whitespace — before you type it into an exam portal. It is built for candidates filling application, admit-card download or answer-key challenge forms, where a single lookalike character (letter O for zero, letter I for one) causes a 'record not found' error. Presets cover common formats such as 12-digit JEE Main application numbers and 8-digit CBSE roll numbers, and a custom mode lets you encode any rule from your own admit card.
Open Roll Number Format Validator on AltFTool — it loads instantly in your browser.
Paste your code or data sample into the workspace.
Pick the format, conversion, or analysis you need.
Copy the polished result straight back into your project.
Flags O vs 0, I/l vs 1, S vs 5 and B vs 8 when a digits-only format fails.
Finds leading, trailing and embedded spaces that portals reject or silently store.
Set exact length, character set and prefix straight from your own admit card.
The most common causes are a lookalike character (the letter O typed instead of the digit 0, or I instead of 1), a hidden space copied along with the number, or a missing digit. Paste the number into this validator with the format from your admit card and it will show exactly which structural check fails.
JEE Main application numbers issued by the NTA are 12-digit numeric strings, typically beginning with digits derived from the exam year. Formats can change between cycles, so treat the number printed on your own confirmation page or admit card as final.
No. The application or registration number is issued when you fill the form, while the roll number is usually assigned later on the admit card, and the two often have different lengths. Portals ask for a specific one, so check the field label before pasting either.
No — it validates structure only (length, characters, prefix and spacing), not whether the number is registered in the exam body's database. If the format passes here but the portal still rejects it, contact the exam helpdesk with your confirmation page.