useful

(as) useful as a chocolate teapot

Utterly useless (because pouring boiling water into a chocolate teapot would melt it). That umbrella is stuck inside out, so it's about as useful as a chocolate teapot right now.
See also: chocolate, teapot, useful

(as) useful as tits on a bull

vulgar slang Utterly ineffectual, worthless, or unnecessary. Primarily heard in Australia. Hey, thanks for the broken wrench—it's as useful as tits on a bull. I know next to nothing about computers, so I'd be useful as tits on a bull trying to figure out what's wrong with your laptop.
See also: bull, on, tit, useful

come in useful

To be especially helpful, often in a particular setting or situation. 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.
See also: come, useful

make (oneself) useful

To do something that is actively helpful or of assistance to others. You know, instead of just sitting there watching TV, you could make yourself useful and take out the garbage. Towards the end of the party, I decided to make myself useful and wash the dishes.
See also: make, useful
Farlex Dictionary of Idioms.

come in useful

to be useful. Your report has come in useful a number of times.
See also: come, useful
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

ˌcome in ˈhandy/ˈuseful

(informal) be useful when needed: The money my aunt gave me will come in handy to pay for my music lessons.
See also: come, handy, useful

make yourself ˈuseful

help other people: Come on, Hannah. Make yourself useful and peel those potatoes for me.
See also: make, useful
Farlex Partner Idioms Dictionary
See also:
  • (as) useful as a chocolate teapot
  • teapot
  • chocolate
  • as much use as a chocolate fireguard
  • chocoholic
  • mint chocolate chip
  • (right) up there with (someone or something)
  • be (right) up there with (someone or something)
  • better than sex
  • a road to nowhere
References in periodicals archive
. Stomach-related diseases: Intake of five gram of Durva Panchang and water is very useful to control vomiting.
Bermuda grass, an ancient cure for ailments
Majority of populace consider branchless banking a useful mean for paying monthly utility bills for electricity, gas, sewerage and Internet, a latest survey has revealed.
67 % populace believes utility bills payment via mobile useful innovation
Useful is a mobile-first app for small to medium sized businesses that need to better track the jobs being performed by their workers in the field.
Useful Closes Seed Round Financing
"Besides the essential baby products such as pushchairs, child car seats, cots and Moses baskets, we rounded up the 10 most useful baby products rated by the parents it quizzed."
Mind that child cost; Pregnant consumer editor EMMA MCKINNEY reveals the baby products worth splashing some cash on... and those deemed a waste of money
He added that he believed finance could play a socially useful and an economically useful function.
-Carney urges banks to be socially useful
The construction of the index is a useful lesson for other researchers in its methodology.
Transportation Indicators and Business Cycles
Specialized business publications rank second, with 67% calling them very useful, a two-point drop from 2004.
Internet no. 1 as 'very useful' info resource, specialized pubs no. 2: survey
This, says Mastercard, is especially true in Saudi Arabia, where 87 per cent of respondents would find a prepaid remittance card useful and 85 per cent would find a pre-paid travel card useful.
MasterCard in new prepaid programme
MANUFACTURERS have voted the Engineering Employers Federation their most useful agency or organisation for the sixth year running in the Annual Manufacturing Report, published by The Manufacturer magazine.
EEF gets the vote; In association with RBS
By introducing these genes into mammalian cells new cell lines with novel and useful properties can be prepared more efficiently than by relying on the natural rate of mutation or introduction of mutations by chemical mutagens.
Morphotek obtains United States patent
Scottish scientists have genetically engineered hens that can not only produce useful drugs in their eggs but also reliably pass on this characteristic to new generations of chickens.
Golden eggs: engineered hens lay drugs
Leading People Through Disasters is indeed, as the subtitle states, an action guide" for all communicators, but it's especially useful for human resource professionals and those who are relatively inexperienced in crisis communication.
The human side of crises: two HR practitioners outline the key steps to building a realistic disaster communication plan--with people at the forefront
Foreign National Tax Guide (www.thetaxguy.com/nrtaxguide.htm) is useful for advising foreign nationals on U.S.
Foreign National Tax Guide
The proposed regulations expand the standards in the current regulations, and provide guidance on the economic useful life of a unit of property and activities that prolong that useful life.
Proposed regulations on capitalization of tangible assets