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In the SSC CHSL Data Entry Test (DEO), mistakes are not all equal. A wrong, missing or extra word, or a spelling mistake, counts as 1 mistake. A capital letter, punctuation or spacing error counts as ½.
Your error percentage must stay within the limit for your category. UR is 5%. OBC/EWS, SC/ST and PwD are 7%. So knowing which slip costs 1 and which costs ½ helps you decide where to be careful.
Below, we go through the rule, the limits, and a calculation you can follow with a pen. The rules are from the SSC CHSL 2026 notice and the 2024/2025 final result notices, and we last checked them on 2026-09-23.
At a glance
| Exam | SSC CHSL Data Entry Test (DEO) |
|---|---|
| Conducted by | Staff Selection Commission (SSC), for Data Entry Operator |
| Language | English |
| Speed | 8,000 key depressions per hour (kdph) for most departments |
| C&AG posts | 15,000 key depressions per hour |
| Test time | 15 minutes |
| Full mistake | Counts 1 |
| Half mistake | Counts ½ |
| Backspace | Allowed |
| Passage length | Not given here. Check the official notice |
The rule in one line
Add up all full mistakes (1 each) and all half mistakes (½ each). Then check that your error percentage is within the limit for your category.
That is the whole idea. The details below show what goes in each group, so you can spot your own weak points during practice.
What counts as a full mistake
These count 1 each:
- Wrong word: you typed a different word from the passage.
- Missing word: you skipped a word.
- Extra word: you typed a word that is not in the passage.
- Spelling mistake: the word is there, but a letter is wrong, missing or extra.
Skipping a line is the most costly slip. If you jump over a line of ten words, that can mean ten missing words. Keep your eyes on the line you are typing and use the pause at the line end to find the next one.
What counts as a half mistake
These count ½ each:
- Capital letters: a small letter where a capital is needed, or the other way round.
- Punctuation: a missing, wrong or extra comma, full stop and so on.
- Spacing: a missing space, or a double space.
Half mistakes look small, but they pile up. Many candidates lose marks on spacing, especially when they type fast and press the space bar twice. Two half mistakes cost the same as one wrong word.
Error limit for each category
| Category | Error limit |
|---|---|
| UR | 5% |
| OBC/EWS | 7% |
| SC/ST | 7% |
| PwD | 7% |
The exact number of mistakes you can make depends on the passage length and how the notice defines the base for the percentage. We do not have the passage length here, so check the official notice. The worked example below uses an assumed length only to show the method.
A worked example with full and half mistakes
Take the calculation step by step in the box above. It uses an assumed passage of 400 words. This number is for practice only. It is not from the notice.
Notice what happens with the allowed limit. At 400 words, 5% is 20 mistakes and 7% is 28 mistakes. A candidate with 11.5 mistakes is well inside both limits. But a candidate who makes 30 half mistakes, such as spacing and punctuation slips, has 15 mistakes. That is still fine for UR here, but it is already three quarters of the allowance.
Speed and time
The speed rule is 8,000 key depressions per hour for most departments. C&AG posts need 15,000. The test time is 15 minutes.
As plain arithmetic, 8,000 per hour is about 133 key depressions a minute, or about 2,000 in 15 minutes. Use this only as a practice target. The way the test measures your speed is in the official notice, so read it before the exam.
Backspace is allowed. Use it to fix a mistake you notice straight away. But do not go back far. Going back three words to fix a comma wastes more time than the half mistake would cost.
How to practise with these rules
Practise on the SSC CHSL Data Entry Test practice page. After each test, sort your mistakes into full and half. Write the two totals on paper.
If full mistakes are higher, slow down a little and read ahead by one word. If half mistakes are higher, focus on the space bar, capitals and punctuation. You can read the published rules on the exam rules page. Our earlier post, SSC CHSL Typing Test: Full and Half Mistakes Explained, covers the same rule from another angle.
The typing test at a glance
- Language
- English
- Speed
- 8,000 kdph (15,000 kdph for C&AG posts)
- Time
- 15 minutes
- Passage length
- Check the official notice
- Error limit
- UR 5%; OBC/EWS 7%; SC/ST 7%; PwD 7%
- Full mistake
- Wrong, missing or extra word; spelling mistake. Counts 1
- Half mistake
- Capital letters, punctuation, spacing. Counts ½
- Backspace
- Allowed
Worked example
Counting mistakes in a 400-word passage (assumed length, for practice only)
- Count the full mistakes: 4 wrong words, 2 missing words, 1 extra word. That is 7 full mistakes, so 7 × 1 = 7.
- Count the half mistakes: 3 capital letter errors, 4 punctuation errors, 2 spacing errors. That is 9 half mistakes, so 9 × ½ = 4.5.
- Add both: 7 + 4.5 = 11.5 mistakes.
- Find the error percentage: 11.5 ÷ 400 × 100 = 2.875%.
- Compare with your category limit: UR is 5%, OBC/EWS, SC/ST and PwD are 7%. 2.875% is inside all of them.
Result: 11.5 mistakes, or 2.875%. This is within the limit for every category in this example. Always confirm the passage length and counting base in the official notice.
What to do this week
- After every practice test, write down your full mistakes and half mistakes separately.
- Check your category limit today: UR 5%, OBC/EWS 7%, SC/ST 7%, PwD 7%.
- Watch your space bar for one full test and count how many double spaces you make.
- Do not skip words to save time. A missing word costs 1, twice as much as a punctuation slip.
- Practise full 15-minute tests so your hands and eyes get used to the whole time.
- If you apply for a C&AG post, remember the speed is 15,000 kdph, not 8,000.
Questions students ask
How much is a full mistake in the SSC CHSL DEO typing test?
A full mistake counts 1. It is a wrong, missing or extra word, or a spelling mistake.
How much is a half mistake?
A half mistake counts ½. It covers capital letters, punctuation and spacing.
What is the error limit?
UR 5%. OBC/EWS 7%. SC/ST 7%. PwD 7%.
Is backspace allowed?
Yes, backspace is allowed.
What is the typing speed required?
It is 8,000 key depressions per hour for most departments. C&AG posts need 15,000. The test time is 15 minutes.
What is the passage length?
We do not have it here. Check the official SSC notice.
Prepared with AI help and checked by the ANR Typing team.
