The short answer
The word percent comes from the Latin per centum, meaning “per hundred” — the meaning of “cent” (hundred) is already built into it. Saying “cent percent” is like saying “hundred per hundred” — you are repeating the same idea twice. Just say hundred percent or 100%.
Wrong vs. Right
Wrong
I am cent percent sure about this.
Right
I am a hundred percent sure about this.
Wrong
He scored cent percent marks in the test.
Right
He scored a hundred percent marks in the test.
Wrong
The plan is cent percent correct.
Right
The plan is a hundred percent correct.
Wrong
Attendance was cent percent this month.
Right
Attendance was a hundred percent this month.
Why Do People Say It?
Many speakers already know “cent” from words like century (a hundred years) and percentage itself, and start treating “cent” as a standalone word meaning “hundred”. Swapping it in for “hundred” before “percent” feels perfectly logical — but it misses that “percent” is not two separate ideas; the word itself already means “per hundred”.
The phrase is extremely common in Indian spoken and even written English — “cent percent attendance”, “cent percent result” — but it is marked as an error in formal writing, competitive exams, and international communication.
How this appears in SSC CGL error spotting
“The school achieved / cent percent results / in the board examination / this year. / No error.”
(A) The school achieved
(B) cent percent results ✓ Error here
(C) in the board examination
(D) No error
Answer: (B) — “cent percent” is redundant. The correct phrase is “hundred percent results”.
Same Mistake, Different Words
“Cent percent” belongs to a family of errors called redundant expressions — where one word already contains the meaning of another word placed next to it:
| Wrong | Correct | Why |
|---|---|---|
| cent percent | hundred percent | 'percent' already means 'per hundred' — 'cent' repeats it |
| revert back | revert | 'revert' already means 'go back' |
| return back | return | 'return' already means 'go back' |
| repeat again | repeat | 'repeat' already means 'do again' |
| free gift | gift | a gift is always free |
| past history | history | history is always past |
Exam tip
Whenever a number word is stacked directly in front of “percent” or “per cent” and that word also means “hundred” — like “cent” — mark it as an error immediately. There is no context in which “cent percent” becomes acceptable in standard or exam English.
Frequently Asked Questions
Why is 'cent percent' wrong?+
'Percent' comes from the Latin 'per centum', meaning 'per hundred' — the word 'cent' (hundred) is already built into it. Saying 'cent percent' is like saying 'hundred per hundred', which repeats the same meaning twice instead of expressing '100 percent'. The correct form is simply 'hundred percent' or '100%'.
Why do Indians say 'cent percent' instead of 'hundred percent'?+
Many Indian languages and Indian English speakers are familiar with 'cent' from words like 'century' and 'percentage', and treat 'cent' as a standalone word meaning 'hundred'. Substituting it for 'hundred' before 'percent' feels natural, but it misses that 'percent' already contains that exact meaning — making the phrase redundant rather than simply informal.
Is 'cent per cent' also wrong?+
Yes, for the same reason. Whether written as one word ('percent') or two ('per cent'), the phrase already means 'per hundred'. Adding 'cent' in front — 'cent percent' or 'cent per cent' — is redundant in every form. Always use 'hundred percent' or '100%' instead.
Read Next
Why Is 'Revert Back' Wrong?
Same redundancy family — 'revert' already means go back
Why Is 'Informations' Wrong?
Uncountable nouns that never take a plural -s
Indian English Errors Hub
All Indianisms — why they exist and what to say instead
Error Spotting MCQs — 100 Questions
Practice sets 1–10, timed with scoring