“What’s the big deal? They mean the same thing.” True. “Less” and “fewer” have similar meanings, but they frequently are misused. When that happens, it’s a grammar mistake that can leave your audience with less than they bargained for.
Luckily, there’s a quick and easy way to remember when to use these two similar words. Just ask yourself if the noun that follows is countable. If the answer is yes, you’ll use “fewer.” If the answer is no, you’ll use “less.”
For example, let’s use the plural noun “syringes.” You can count syringes, so in this case, you would use “fewer.” I have fewer syringes to use for the COVID-19 vaccine today than I had yesterday.
Let’s use “water” as an example of a noun that you can’t count. In this case, you would use “less than.” I have less water to hand out to patients today than I had yesterday.
Fewer = not as many
Less = not as much