Claude Sonnet 4.5 vs GPT-4o
Anthropic vs OpenAI · Prices checked 12 August 2026
GPT-4o is 28 per cent cheaper on blended cost, $4.75 per million tokens against $6.60. A single 100K-input, 10K-output job costs $0.350 on GPT-4o against $0.450 on Claude Sonnet 4.5.
Claude Sonnet 4.5 leads on 5 of the 6 benchmarks both models report. The widest gap is on SWE-bench Verified, where Claude Sonnet 4.5 leads by 29 points. Claude Sonnet 4.5 takes a 200,000-token context window against 128,000, giving a modest edge for long documents or whole-codebase work. Claude Sonnet 4.5 was released Sep 2025; GPT-4o May 2024.
Pricing and capacity
| Metric | Claude Sonnet 4.5 | GPT-4o | Difference |
|---|---|---|---|
| Input / 1M tokens | $3.00 | $2.50 | 17% |
| Output / 1M tokens | $15.00 | $10.00 | 33% |
| Blended · 70/30calculated | $6.60 | $4.75 | 28% |
| Blended · 50/50calculated | $9.00 | $6.25 | 31% |
| Blended · 80/20calculated | $5.40 | $4.00 | 26% |
| Blended · 20/80calculated | $12.60 | $8.50 | 33% |
| Job cost · 100K + 10Kcalculated | $0.450 | $0.350 | 22% |
| Job cost · 1M + 100Kcalculated | $4.50 | $3.50 | 22% |
| Context window | 200,000 | 128,000 | 36% |
Input and output rates are as published by each provider. Blended and job-cost rows are calculated comparison metrics, not published prices — how they are derived.
Benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-4o | Leader |
|---|---|---|---|
| MMLU | 85% | 88% | GPT-4o |
| GPQA Diamond | 73% | 53% | Claude Sonnet 4.5 |
| MATH | 86% | 76% | Claude Sonnet 4.5 |
| HumanEval | 91% | 90% | Claude Sonnet 4.5 |
| SWE-bench Verified | 62% | 33% | Claude Sonnet 4.5 |
| LMArena Elo | 1340 Elo | 1316 Elo | Claude Sonnet 4.5 |
Only suites both models report are listed, so a missing score is never shown as a loss. Figures are provider-published or from public leaderboards and are not independently re-run.
What each model is for
Claude Sonnet 4.5
Anthropic · Balanced
The Sonnet that established the Claude 4 line as the default mid-tier choice. Still widely deployed where 4.6 hasn't been re-validated.
- Strong coding for the price
- 1M context
- Solid vision
- Wide ecosystem support
Frequently asked questions
Which is cheaper, Claude Sonnet 4.5 or GPT-4o?
GPT-4o is 28 per cent cheaper on blended cost, $4.75 per million tokens against $6.60. A single 100K-input, 10K-output job costs $0.350 on GPT-4o against $0.450 on Claude Sonnet 4.5. Blended cost weights input at 70% and output at 30%; price your own token split for an exact answer, since the cheaper model on a blended basis is not always cheaper for your workload.
Which performs better, Claude Sonnet 4.5 or GPT-4o?
Claude Sonnet 4.5 leads on 5 of the 6 benchmarks both models report. The widest gap is on SWE-bench Verified, where Claude Sonnet 4.5 leads by 29 points. These are the figures each provider or public leaderboard publishes, not results we re-run, and a benchmark average can hide the specific behaviour your workload depends on.
Which has the larger context window, Claude Sonnet 4.5 or GPT-4o?
Claude Sonnet 4.5 takes a 200,000-token context window against 128,000, giving a modest edge for long documents or whole-codebase work. The context window caps everything in a single request: prompt, retrieved documents, conversation history and the model’s own output all share it.
Can I compare Claude Sonnet 4.5 and GPT-4o on my own numbers?
Yes. Open both in the side-by-side comparison tool to see every field at once, or use the token calculator to price your actual prompt and monthly request volume against each model. Both are free and need no sign-up.
Price it for your own workload
Related matchups
Terms used on this page
Prices and scores are recomputed on every deploy from the catalogue. Prices checked 12 August 2026.