Subscription vs API: When Does a Claude or Codex Plan Pay Off?
Updated 2026-10-25. API prices from models.json; plan prices from claude.com/pricing and developers.openai.com/codex/pricing, checked Oct 24, 2026.
Your usage
Optional: tool prompt overhead
Overhead tokens = overhead per step × steps, added to input tokens and billed at the same cache-hit %. Cache-write fees are left out, so real API costs can be a little higher.
Result
| Plan | Price/month | Break-even tasks/month | Cheaper for you | Published usage limits |
|---|
Break-even tasks per month = plan price / API cost per task. Above it the plan is cheaper, but only if your usage fits inside the plan's limits.
Plan limits (official)
- Claude Pro and Max: both have a 5-hour session limit and a weekly limit, shared between Claude and Claude Code. Anthropic publishes no numeric caps, so we can't say how many tasks a plan covers. Max is "from $100" with 5x or 20x Pro's usage; the 20x price isn't shown on the pricing page. (pricing, limits)
- Codex Plus ($20): OpenAI's estimated local messages per 5 hours: GPT-6 Astra 5–45, GPT-6.1 Sol 15–160, GPT-6 Sol 15–150, GPT-6 Luna 350–3,000. Weekly limits may also apply; no weekly numbers are published.
- Codex Pro ($100, $200 or $500): "Pro plans currently have no five-hour limit." Weekly limits may apply. Fast mode burns included usage 2.5× faster. (source)
Harness overhead: the same model can cost up to 3× more
The paper "What Does a Harness Buy? Tokens, Mostly" (arXiv 2610.04433) found that with the same model, cost per task varies up to 3× across Claude Code, OpenCode and mini-SWE-agent at similar pass rates. Each tool resends a fixed prompt every step: about 16.6k tokens for Claude Code, 7.0k for OpenCode and 0.8k for mini-SWE-agent. Use the overhead presets above to see how that changes your API bill.
Open the TokenTab calculator Claude Code cost per month Claude Code vs Codex cost