Claude Opus 4.8 vs GPT-5.1
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Claude Opus 4.8
Anthropic · May 2026
Anthropic's flagship Opus with adaptive thinking, effort controls and a 1M context — 88.6% on SWE-bench Verified at $5/$25.
GPT-5.1
59.6OpenAI · Nov 2025
A November 2025 update to GPT-5 with adaptive reasoning that spends thinking tokens only when a task needs them.
The verdict
Claude Opus 4.8 wins 3 of the 3 benchmarks these models share, against 0 for GPT-5.1. GPT-5.1 is about 2.9x cheaper per blended million tokens (3:1 input:output mix). Claude Opus 4.8 also takes 1M of context versus 400K for GPT-5.1.
Benchmark head-to-head 3–0
Specs & pricing
| Claude Opus 4.8 | GPT-5.1 | |
|---|---|---|
| modhub Index | — | 59.6 |
| Input price / 1M | $5 | $1.25 |
| Output price / 1M | $25 | $10 |
| Context window | 1M | 400K |
| Max output | 64K | 128K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Mar 2026 | Sep 2024 |
| Released | May 2026 | Nov 2025 |
| Example monthly cost* | $87.50 | $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 Opus 4.8 or GPT-5.1?
- Claude Opus 4.8 wins 3 of the 3 benchmarks these models share, against 0 for GPT-5.1. GPT-5.1 is about 2.9x cheaper per blended million tokens (3:1 input:output mix). Claude Opus 4.8 also takes 1M of context versus 400K for GPT-5.1.
- Which is cheaper, Claude Opus 4.8 or GPT-5.1?
- Claude Opus 4.8 costs $5/$25 per million input/output tokens, while GPT-5.1 costs $1.25/$10. For a typical workload of 10M input and 1.5M output tokens per month, that's $87.50 versus $27.50.
- Which model is better for coding, Claude Opus 4.8 or GPT-5.1?
- On SWE-bench Verified — the standard agentic-coding benchmark — Claude Opus 4.8 scores 88.6% versus 76.3% for GPT-5.1, making Claude Opus 4.8 the stronger pick for coding agents.