Comparison · prices as of 2026-07-04 · re-verified 2026-08-18
Claude Sonnet 4.5 vs GPT-5 mini
On price alone, GPT-5 mini (OpenAI) runs about 89% cheaper than Claude Sonnet 4.5 for a typical chat workload (2K input + 500 output tokens, 1,000 requests/day). Whether that's the right trade depends on the capability gap — the breakdown below shows where each one wins.
Price per million tokens
| Spec | Claude Sonnet 4.5 | GPT-5 mini |
|---|---|---|
| Input / MTok | $3 | $0.25 |
| Output / MTok | $15 | $2 |
| Context window | 200K | 400K |
| Max output | 64K | 128K |
| Class | workhorse | workhorse |
Estimated monthly cost by workload
Same models, three realistic usage levels. The gap between them scales with volume, so the right pick can change as you grow.
| Workload | Claude Sonnet 4.5 | GPT-5 mini | Cheaper |
|---|---|---|---|
| Light — chatbot 0.5K in / 0.2K out · 200 req/day | $27.00 | $3.15 | GPT-5 mini |
| Typical — assistant 2K in / 0.5K out · 1K req/day | $405 | $45.00 | GPT-5 mini |
| Heavy — RAG / agent 8K in / 2K out · 5K req/day | $8,100 | $900 | GPT-5 mini |
Which should you pick?
- Cheapest overall: GPT-5 mini — about 89% less per month on a typical assistant workload.
- GPT-5 mini is cheaper on both input and output, so it stays cheaper whether your workload is prompt-heavy or generation-heavy.
- Largest context window: GPT-5 mini at 400K tokens vs 200K — the one to pick if you feed in whole documents or codebases.
Frequently asked questions
Is Claude Sonnet 4.5 or GPT-5 mini cheaper?
GPT-5 mini is cheaper — roughly 89% less per month on a typical assistant workload (2K input + 500 output tokens, 1,000 requests/day).
What do Claude Sonnet 4.5 and GPT-5 mini cost per million tokens?
Claude Sonnet 4.5 is $3 per million input tokens and $15 per million output. GPT-5 mini is $0.25 input and $2 output. Prices are first-party API list rates as of 2026-07-04.
Which has the larger context window, Claude Sonnet 4.5 or GPT-5 mini?
GPT-5 mini does, at 400K tokens versus 200K for Claude Sonnet 4.5.
When should I choose Claude Sonnet 4.5 over GPT-5 mini?
Both are workhorse-class models, so choose Claude Sonnet 4.5 when it measurably wins on your own evals or you prefer its provider (Anthropic); otherwise GPT-5 mini does the same job for less.
Related comparisons
Sources: Anthropic pricing · OpenAI pricing. Run your own numbers in the cost calculator.