GPT-5.1 vs OpenAI o3
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
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.
OpenAI o3
68.9OpenAI · Apr 2025
OpenAI's dedicated 2025 reasoning model that pioneered thinking-with-images and agentic tool use within chain-of-thought.
The verdict
GPT-5.1 wins 3 of the 3 benchmarks these models share, against 0 for OpenAI o3. GPT-5.1 is about 1.0x cheaper per blended million tokens (3:1 input:output mix). GPT-5.1 also takes 400K of context versus 200K for OpenAI o3.
Benchmark head-to-head 3–0
Specs & pricing
| GPT-5.1 | OpenAI o3 | |
|---|---|---|
| modhub Index | 59.6 | 68.9 |
| Input price / 1M | $1.25 | $2 |
| Output price / 1M | $10 | $8 |
| Context window | 400K | 200K |
| Max output | 128K | 100K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Sep 2024 | May 2024 |
| Released | Nov 2025 | Apr 2025 |
| Example monthly cost* | $27.50 | $32.00 |
* 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, GPT-5.1 or OpenAI o3?
- GPT-5.1 wins 3 of the 3 benchmarks these models share, against 0 for OpenAI o3. GPT-5.1 is about 1.0x cheaper per blended million tokens (3:1 input:output mix). GPT-5.1 also takes 400K of context versus 200K for OpenAI o3.
- Which is cheaper, GPT-5.1 or OpenAI o3?
- GPT-5.1 costs $1.25/$10 per million input/output tokens, while OpenAI o3 costs $2/$8. For a typical workload of 10M input and 1.5M output tokens per month, that's $27.50 versus $32.00.
- Which model is better for coding, GPT-5.1 or OpenAI o3?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.1 scores 76.3% versus 69.1% for OpenAI o3, making GPT-5.1 the stronger pick for coding agents.