Don't Mess Up Your CAT 2026 Form: Critical Mistakes to Avoid
Published 10 July 2026 · 4 min read · Common Admission Test
The form seems simple, which is exactly why people get careless. These mistakes cost money, choices or a valid application.
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Filling the CAT form looks routine. That is exactly why people get careless and pay for it. Some mistakes cost you a rejected photo. Some cost you a category benefit you were entitled to. A few you cannot undo after final submission. Here are the biggest CAT 2026 form-filling mistakes, with how to sidestep each one.
At a Glance
Item | Detail |
|---|---|
Registration window | Opens August, closes about mid-September 2026 |
Costliest mistake | A wrong category entry you cannot change later |
Most common | A photo or signature that fails the upload specs |
Sneaky one | An OBC-NCL certificate not issued after 1 April 2026 |
Golden rule | Preview everything before you hit final submit |
Fee | Around 2,600 rupees, roughly half for SC, ST and PwD |
Mistake 1: getting the photo and signature specs wrong
The most common trip-up. A selfie, a blurry scan, a black-and-white image or a file over 80 KB gets flagged. You then redo it under time pressure. Prepare a colour photo of about 1200 by 1200 pixels and a clean signature scan, both under 80 KB, before you open the form. A free online image resizer gets both to the right size in a minute.
Mistake 2: entering the wrong category
This is the expensive one. Your category, whether general, EWS, NC-OBC, SC, ST or PwD, feeds into cutoffs and shortlisting. Pick it carefully and match it to a valid certificate. Get it wrong, or claim one you cannot support with a certificate. Either way, you can lose the benefit or the application. In many cases you cannot change it after submission, so slow down here.
Mistake 3: an expired or wrongly dated certificate
People upload the certificate they already have without checking the date. For CAT 2026, an OBC-NCL certificate has to be issued after 1 April 2026. An older one is not valid. If yours predates that, begin the renewal now rather than discovering the problem on the last day.
Mistake 4: careless academic and personal details
Field | Common slip |
|---|---|
Name | Spelling that does not match your ID |
Class 10 and 12 marks | Rounding or typing the wrong percentage |
Graduation | Wrong aggregate or wrong final-year status |
Work experience | Wrong number of months |
These feel trivial, but mismatches surface later at interview verification and can cause real trouble. Fill every number straight from the original document, not from memory.
Mistake 5: rushing the programme choices and the final submit
The form lets you pick which IIM programmes to apply to. Do not rush this list, since adding a programme later can mean extra fees or a missed chance. And never hit final submit without previewing the whole form. Once submitted, many fields lock. Read every page once, confirm the photo and category, then submit.
Mistake 6: leaving it to the last day
The portal slows to a crawl in the final 48 hours. A payment glitch or a slow certificate can then cost you the whole application. Fill the form in the first two weeks of the window. Early means calm. Calm means fewer mistakes.
A three-minute check before you submit
Before you pay, run a quick pass. Does the photo display clearly and match the specs? Is the category correct and backed by a valid certificate? Do your class 10, 12 and graduation numbers match your marksheets exactly? Is your name spelled as on your ID? Is your programme list complete? Five clean yes answers, then submit. This one habit prevents almost every costly mistake above.
Frequently Asked Questions
What is the most common CAT form mistake?
A photo or signature that fails the upload specs, usually a selfie, a blurry scan or an oversized file. Prepare both to spec before you start.
Can I change my category after submitting the CAT form?
Often not. Category feeds into shortlisting. Many fields lock after final submission. Choose carefully and match it to a valid certificate.
What is the OBC certificate rule for CAT 2026?
The OBC-NCL certificate has to be issued after 1 April 2026 to be valid. An older certificate will be rejected, so renew it early if needed.
When should I fill the CAT 2026 form?
In the first two weeks of the August window. The portal gets slow near the deadline, so last-minute glitches can cost you the application.
How much is the CAT 2026 application fee?
Around 2,600 rupees for general, OBC and EWS applicants. SC, ST and PwD candidates pay about half. Pay only on the official portal.
Should I preview the CAT form before paying?
Always. Once you pay and submit, many fields lock. A two-minute preview of every page catches the errors that are painful to fix later.
Can I edit the CAT form after submitting?
Only within whatever correction window IIM allows, not for every field. Treat the final submit as close to permanent. Preview everything first.
Frequently Asked Questions
What is the most common CAT form mistake?
A photo or signature that fails the upload specs, usually a selfie, a blurry scan or an oversized file. Prepare both to spec before you start.
Can I change my category after submitting the CAT form?
Often not. Category feeds into shortlisting. Many fields lock after final submission. Choose carefully and match it to a valid certificate.
What is the OBC certificate rule for CAT 2026?
The OBC-NCL certificate has to be issued after 1 April 2026 to be valid. An older certificate will be rejected, so renew it early if needed.
When should I fill the CAT 2026 form?
In the first two weeks of the August window. The portal gets slow near the deadline, so last-minute glitches can cost you the application.
How much is the CAT 2026 application fee?
Around 2,600 rupees for general, OBC and EWS applicants. SC, ST and PwD candidates pay about half. Pay only on the official portal.
Should I preview the CAT form before paying?
Always. Once you pay and submit, many fields lock. A two-minute preview of every page catches the errors that are painful to fix later.
Can I edit the CAT form after submitting?
Only within whatever correction window IIM allows, not for every field. Treat the final submit as close to permanent. Preview everything first.