Claude Sonnet 4.5 vs GPT-5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Claude Sonnet 4.5
65.5Anthropic · Sep 2025
The model that made 30-hour autonomous coding sessions real — 77.2% SWE-bench Verified and a 1M-token context beta at $3/$15.
GPT-5
70.7OpenAI · Aug 2025
OpenAI's August 2025 unified flagship that merged the GPT and o-series reasoning lines into one model with selectable effort.
The verdict
GPT-5 wins 4 of the 6 benchmarks these models share, against 2 for Claude Sonnet 4.5. GPT-5 is about 1.7x cheaper per blended million tokens (3:1 input:output mix). GPT-5 also takes 400K of context versus 200K for Claude Sonnet 4.5.
Benchmark head-to-head 2–4
Specs & pricing
| Claude Sonnet 4.5 | GPT-5 | |
|---|---|---|
| modhub Index | 65.5 | 70.7 |
| Input price / 1M | $3 | $1.25 |
| Output price / 1M | $15 | $10 |
| Context window | 200K | 400K |
| Max output | 64K | 128K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Jan 2025 | Sep 2024 |
| Released | Sep 2025 | Aug 2025 |
| Example monthly cost* | $52.50 | $27.50 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, Claude Sonnet 4.5 or GPT-5?
- GPT-5 wins 4 of the 6 benchmarks these models share, against 2 for Claude Sonnet 4.5. GPT-5 is about 1.7x cheaper per blended million tokens (3:1 input:output mix). GPT-5 also takes 400K of context versus 200K for Claude Sonnet 4.5.
- Which is cheaper, Claude Sonnet 4.5 or GPT-5?
- Claude Sonnet 4.5 costs $3/$15 per million input/output tokens, while GPT-5 costs $1.25/$10. For a typical workload of 10M input and 1.5M output tokens per month, that's $52.50 versus $27.50.
- Which model is better for coding, Claude Sonnet 4.5 or GPT-5?
- On SWE-bench Verified — the standard agentic-coding benchmark — Claude Sonnet 4.5 scores 77.2% versus 74.9% for GPT-5, making Claude Sonnet 4.5 the stronger pick for coding agents.