Fewer vs Less

Many writers mix these up. In casual speech, people won’t mind. In careful writing—reports, academic work, policy notes—choosing the right word keeps your meaning precise.

The core difference

Fewer: For countable things (items you can number).
Less: For uncountable quantities (amount, mass, time, money in total, distance as a single measure, probability, etc.).

They both reduce something, but one reduces the number, the other reduces the amount.

How to use each one

Fewer (countable)

Use with plural, countable nouns.

Fewer errors were found in Revision 2.
Fewer patients missed the follow-up visit.
The lab logged fewer incidents this quarter.

Less (uncountable)

Use with mass/measure nouns or singular abstractions.

Patients reported less pain after 24 hours.
The protocol uses less solvent and less time.
There is less interest in the extended warranty.

Illustrative examples (simple to technical)

Everyday

Fewer tickets were left for the evening show.
I spent less money this month.

Business/management

Fewer support tickets reached Tier-2.
The redesign led to less downtime overall.

Science/medical writing

Fewer adverse events occurred in the active arm.
The reformulation generated less particulate matter.

Data/methods

Fewer outliers remained after trimming.
The new model shows less variance at high SNR.

When clarity matters most (edge cases)

1. Countable vs uncountable packaging

Incorrect: We need fewer volunteers tomorrow. Correct: We need fewer volunteers tomorrow.

2. Time, money, and distance as total measures

Correct: The trial finished in less than 8 weeks.
Correct: The project cost less than ₹10 lakh. (“Less” is fine here because we treat these as single amounts.)

3. Percentages and fractions

If the thing itself is countable, fewer can fit; otherwise, less is safer.
Correct: Fewer than 5% of patients withdrew.
Correct: Less than 5% withdrawal was observed.

4. “Fewer/less number of” (wordy)

Incorrect: A smaller number of defects were seen. Correct: Fewer defects were seen. Correct (amount): Less defect density was seen.

5. With comparatives before a plural unit

Common in signage/idiom: “10 items or less.” In formal writing, prefer “10 items or fewer.”
Correct (formal): Participants with fewer than 10 sessions were excluded.

One-line memory hook

Fewer = number (countable).

Less = amount (uncountable or total measures).