GPT-5.6 vs Claude Sonnet 5: API pricing
OpenAI's GPT-5.6 against Anthropic's Claude Sonnet 5 on price alone — per-token rates, caching, and context window. Run your own workload through both with the calculator below; capability differences are yours to judge on your evals.
| GPT-5.6 | Claude Sonnet 5 | |
|---|---|---|
| Input / 1M tokens | $4.00 | $2.00 |
| Cached input / 1M | $0.40 | $0.20 |
| Output / 1M tokens | $20.00 | $10.00 |
| Context window | 922K | 1M |
| Max output | 125K | 125K |
| Vendor | OpenAI | Anthropic |
Prices last synced Oct 4, 2026 from the LiteLLM community price catalog — the same catalog Marginal prices real usage events against, refreshed daily. Spot an error? Tell us.
Price takeaways
- Input: Claude Sonnet 5 is 2x cheaper.
- Output: Claude Sonnet 5 is 2x cheaper.
- Cached input: Claude Sonnet 5 is 2x cheaper.
- Ratios shift with workload shape — output-heavy traffic weights the output rate, cache-friendly traffic weights the cached rate. The calculator below does the arithmetic on your numbers.
Your workload on both
Your monthly workload
Cache hit rate = share of input tokens served from the provider's prompt cache, billed at the model's cached-input price. Estimates use standard per-token rates — batch discounts, service tiers, and long-context surcharges are not applied.
| Model | Input | Cached input | Output | Per request | Monthly |
|---|---|---|---|---|---|
| Claude Sonnet 5cheapest | $1,200 | $80.00 | $2,500 | $0.00756 | $3,780 |
| GPT-5.6 | $2,400 | $160 | $5,000 | $0.015 | $7,560 |
Related comparisons
Switching models? Watch the bill move in real time.
Marginal prices every call against that day's rates, so an A/B between these two shows up as dollars per customer and feature — not a surprise at month end.