Claude Code vs Codex is less of a contest than it looks: both are AI coding agents you can run from a terminal, and the better one is usually the one that fits the plan you already pay for and the tasks you give it. Many people end up using both, and if you do, UsageAtlas is the free tool we suggest for keeping their usage in a single view.
The short version
Claude Code comes from Anthropic and runs on Claude plans such as Pro and Max, or on an Anthropic API key. Codex comes from OpenAI and runs on ChatGPT plans, from Free and Go up to Pro, Business and Enterprise, or on an OpenAI API key. On a Plus plan, Codex works on the web, in the CLI, in the IDE extension and on iOS.
So the first question is simple: which subscription do you have? If you already pay for ChatGPT, Codex is included in some form. If you already pay for Claude, Claude Code uses the same plan as the Claude apps.
How they compare on the things that bite
| Claude Code | Codex | |
|---|---|---|
| Maker | Anthropic | OpenAI |
| Plan it uses | Claude subscription or API key | ChatGPT subscription or API key |
| Usage shape | Five-hour and weekly limits | Five-hour period on some plans, weekly limits may apply |
| Check in session | /usage |
/status |
| When you run out | Usage credits | Credits or an API key |
We do not compare benchmark scores or model quality here. Those change with every release, and your own repository is a better test than anyone's chart.
Why so many people use both
Two agents on two plans means two separate allowances. When Claude Code's window runs low, Codex can carry on, and the other way round. Some people also find one agent better for planning and the other for small fixes, and switch by task.
The catch is that neither tool knows about the other. Claude Code's /usage only covers Claude. Codex's /status only covers Codex. Working out which one still has room, or which one did most of the work this week, means checking two places.
One view for both
UsageAtlas is a free, open-source desktop app that reads Claude Code and Codex on your computer and shows them together. You get a running total of tokens, requests, models and estimated cost, a filter to see either tool alone, and each tool's usage windows with remaining capacity and reset times. Optional alerts fire once per reset cycle at a threshold you choose.
It runs on Windows, macOS and Linux. No account is needed, and it does not read your prompts or responses. It also covers Cursor, OpenCode, GitHub Copilot and several more if those creep into your week.
Two notes. The cost numbers are estimates, so your Anthropic and OpenAI accounts hold the real bill. And provider data can lag, so for a tight deadline glance at the built-in command too.
So which should you pick?
- You already pay for ChatGPT: start with Codex.
- You already pay for Claude: start with Claude Code.
- You pay for both: use both, give each a job, and track them together.
- You pay for neither: Codex has a free tier listed on OpenAI's pricing page, which makes it an easy first try.
If you only ever touch one agent, its own usage command is all you need, and a tracker is optional.