There's no law, but there is a reader: someone with many applications and a few minutes. Length is a cost you ask them to pay, so every line should earn its place.
A rule of thumb
- Students and early career (under about five years): one page.
- Mid and senior career: up to two pages.
- Academic CVs, and some countries' public sector and medical roles: longer, with publications, grants and teaching listed in full. Follow the field's convention.
What to cut first
- Jobs more than ten to fifteen years ago: keep the title, company and dates.
- Bullets that describe duties rather than results.
- Skills nobody would ask you about.
- "References available on request": it goes without saying.
- Repeated information: if the summary says it, the bullets don't need to.
Make it fit, not shrink
Tiny fonts and narrow margins make a resume harder to read, not shorter. Cut words instead. If a resume runs a few lines over a page, the PDF download on jsonresume.org has a fit-to-one-page option (?fit=1) that scales it down a little, never more than it must.
Different lengths for different jobs
Keep a complete master resume, and a shorter version for each kind of role, so cutting for one application doesn't lose what you need for the next.