Based On vs. Based Off Of
Based On vs. Based Off Of follows Merriam-Webster’s evidence-based usage note: based on is preferred, while based off/off of is newer but attested.
Use based on for the established and broadly accepted form; based off or based off of is newer and may sound less formal to some readers.
Key details
Choose the right form
| Form | Status | Best use |
|---|---|---|
| based on | established and broadly accepted | default in formal/general edited prose |
| based off / based off of | newer, attested | may be acceptable informally but can sound less formal to some readers |
Quick tests
Register test
Do you want the least marked form across formal and international audiences?
If yes: Choose “based on.”
If no: If the document intentionally uses a newer conversational form, “based off/off of” is attested but should match audience and house style.
Caveat: The newer forms are attested; the distinction is preference/register, not permission to label every occurrence ungrammatical.
Examples
The estimate is based on last year’s figures.
“Based on” is the established broadly accepted form.
The story is based off a real event.
The newer form is attested, especially in less formal usage.
For edited professional prose, “based on” is the safer default.
This is a register/style recommendation, not a claim that attested newer variants do not exist.
Further guidance
Core difference
Merriam-Webster identifies based on as the preferred long-established choice; based off and based off of are newer forms used with the same meaning.
Style Boundary
In edited or formal writing, based on is the lower-risk choice because some readers still judge the newer forms as errors or informal.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Is it “based on” or “based off”? (opens in a new tab)Merriam-Webster · Usage guidance on based on versus newer based off/based off of