Quick answer
Both tools bill the same two ways: a subscription with usage windows, or API tokens at model rates. To compare them, run one representative task in each with a fresh session, record input, cached, and output tokens, then apply the current rates for the model you used. Do not compare list prices alone, because context and retries dominate.
Run the comparison
- Choose a task both tools can complete, such as fixing one failing test.
- Start a fresh session in each and use the same prompt.
- Record input, cached input, output, and number of turns.
- Repeat twice to see variance.
- Apply current rates for the selected model in each provider.
| Metric | Why it matters | Where to find it |
|---|---|---|
| Tokens per completed task | The real unit of cost | Local session files |
| Turns to completion | Drives repeated context | Session log |
| Cached share | Discount on repeated prefixes | Token detail view |
| Retry count | Pure waste when it repeats | Transcript |
Where the tools differ
- Codex tends to run longer autonomous loops; Claude Code tends to pause for approval more often. Both change token use.
- Plan windows are structured differently, so a cheap month on one may still hit a short-window limit.
- Model defaults differ; comparing a strong model in one with a small model in the other is not a comparison.
- Both offer API billing, which makes a common rate basis possible.
What the result usually says
Per task, the difference is usually smaller than the difference within one tool across task types. A migration costs many times a bug fix in both. Pick the tool whose workflow you finish faster, then manage cost with session hygiene.
UsageAtlas tracks both from local files, so the comparison uses the same definitions.
Make the comparison fair
Both tools charge for tokens, but the windows, the default models, and the amount of hidden context differ. Comparing a monthly invoice with a weekly cap tells you nothing. Pick one task, run it in both from a clean context, and record the attempts as well as the tokens.
- Same task, same starting point.
- Comparable model class, not the strongest in one tool.
- Record whether the first attempt succeeded.
- Repeat twice before drawing a conclusion.
UsageAtlas tracks both from local session data, so the totals use the same definitions. The Claude Code cost guide covers the other side of the comparison.
Questions, answered
Is Codex cheaper than Claude Code?
Neither is cheaper in general. Cost per task depends on model, context, and retries. Measure one shared task in both before deciding.
Can I compare subscription plans directly?
Only on capacity and price, not on cost per task. Plan allowances are not expressed in tokens, so the two do not convert cleanly.
Which is cheaper for small edits?
The one with the smaller default context. For tiny edits, a smaller model and a fresh session matter more than the brand.