Claude Sonnet 4vso3
Claude Sonnet 4 | o3 | |
|---|---|---|
| API pricingUSD per 1M tokens · lower wins | ||
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it. | — | $2.00 |
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one. | — | $8.00 |
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again. | — | $0.50 |
Cheapest inputLowest input rate across third-party providers, excluding the lab itself. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page. | $3.00Amazon Bedrock | — |
Cheapest outputLowest output rate across third-party providers, excluding the lab itself. May come from a different provider than the cheapest input. | $15.00Amazon Bedrock | — |
| Benchmarks | ||
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 30% | 26% |
| BenchmarksPublished by one model only | ||
SWE-Bench VerifiedCoding — Real coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 72.7% | — |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 75.4% | — |
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | May 22 2025 | Apr 16 2025 |
| Access | Proprietary | Proprietary |
Other comparisons
Frequently asked questions
Claude Sonnet 4 leads o3 on 1 of the 1 benchmark they both report (BullshitBench v2). Only o3 has a verified first-party API price: $2.00 per million input tokens and $8.00 per million output tokens. No pay-as-you-go API rate is tracked for Claude Sonnet 4. o3 shipped 36 days before Claude Sonnet 4, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
On BullshitBench v2, Claude Sonnet 4 leads at 30% vs o3 at 26%.
Claude Sonnet 4 was released by Anthropic on May 22 2025.
o3 was released by OpenAI on Apr 16 2025.
Only o3 has a verified first-party API price: $2.00 per million input tokens and $8.00 per million output tokens. No pay-as-you-go API rate is tracked for Claude Sonnet 4. Rates are pay-as-you-go API prices verified on August 18, 2026.