You asked: What does "it comes in useful" mean in that sentence? (note the corrected word order and preposition) Here are some dictionary definitions: - If an object or skill comes in useful, it can help you achieve something in a particular situation. e.g. "The accommodation is some distance from the clubhouse, so a hire car comes in useful." (Collins) -to be useful and help someone to do or achieve something e.g. "You should keep that paint - it might come in useful one day." (Cambridge) -to be helpful in a particular situation e.g. "Your medical training might come in very useful indeed." (Macmillan) - to be especially helpful, often in a particular setting or situation. e.g. "It was a lot colder out than I thought it would be, so your jacket really came in useful!" "That flashlight comes in useful when I'm trying to find something in my car at night." (Free Dictionary) - to be useful e.g. "Her pocketknife came in useful when we needed to cut the tangled fishing line." (Merriam Webster) Perhaps [email protected] might want to reconsider his view that 'No one says "comes in useful" ' ?

This sentence is wrong. A common phrase is "comes in handy" which simply means "useful". No one says "comes in useful". So this sentence should be either "it comes in handy..." or "it is useful..."

SuKi’s answer is very good, and I can certify that as a native speaker of American English “comes in useful” is commonly used.

Another way to say it is "It can be helpful for measuring quantities...". The phrase "comes in useful" refers to the fact that something can be useful in certain circumstances.