Which subjects do jobs actually use?
Choosing subjects can feel like choosing your future. It isn't quite that, but it helps to know what jobs actually use. Here is what people in hundreds of occupations say they need to know, and what that can and can't tell you about your choices.
What jobs say they use
O*NET, the US government's database of jobs, groups them into occupations, such as “Registered Nurses”, each covering many job titles. It asks the people who do each job how important 33 areas of knowledge are to their work, from 1, “not important”, to 5, “extremely important”. We count 3, “important”, or more as an occupation using it. The areas run from English, maths and biology to customer service, mechanics and marketing.
Across the 910 occupations, three things stand out:
- ✓ English is everywhere. 809 of the 910 occupations rate it important, more than any other area.
- ✓ Customer service outranks maths. Customer and personal service is rated important by 647 occupations, more than maths (521).
- ✓ Some subjects show up in very few occupations as important. History is rated important by 25 occupations and a foreign language by 11.
Try this: history is rated important by only 25 occupations. Does that make it a waste of time?
Ask compared with what? This counts occupations that need historical facts. It doesn't count what studying history trains you to do: weigh sources, build an argument, write it up. Those show up under other names, like English, or critical thinking, which almost every job needs, as the evidence page shows. A subject is more than the facts in it.
Explore it yourself
Pick jobs you're curious about and see which areas they all use. Or start from a subject and see the jobs that use it most, at every level of preparation.
Compare up to three jobs
No job matches that. The names are US job titles, so try a more formal one.
Show every area, side by side
A coloured bar means the job rates that area important or more; a grey one means less.
Start from a subject
What this can't tell you
- What a job uses isn't what it takes to get in. Universities, colleges and employers set their own entry requirements, and they differ from country to country and course to course. A course may ask for a subject the job itself rarely uses. Always check the real requirements for anything you're aiming at.
- It's American, and it's a snapshot. These are US jobs, rated mostly by the people doing them, at different times between 2005 and 2026. Jobs change, and AI is changing some of them faster than the ratings can keep up. See Will AI take that job?
- Each rating is an average. “Software developers” is one occupation covering very different jobs, and so is every other.
- One choice now doesn't settle everything. Much of what jobs use is learned later anyway, at college, in training or on the job. Keep options open where you can, but don't panic about one choice.
Does knowing things still matter if AI can look them up? We think it matters more. You can only judge an AI's answer in a subject you know something about. That's the idea behind Why judging matters more than ever.
The short version
Look for the subjects the jobs you're curious about share, and keep those open if you can. Check the real entry requirements yourself. And remember that a lot of what jobs need is learned later, in further study, training or at work.
Last reviewed: 12 October 2026