# GPT-5.1-Codex vs GPT-5 Pro

> GPT-5 Pro is the stronger model overall, scoring 46.2 to 38.2 on the Noometry Index. GPT-5.1-Codex costs 12× less per token, which makes it the better buy when GPT-5 Pro's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-gpt-5-pro
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in math, where GPT-5 Pro leads 48.0 to 29.3.
- GPT-5.1-Codex is cheaper at $1.25 / $10 per million input/output tokens, against $15 / $120 for GPT-5 Pro.

## Snapshot

| | GPT-5.1-Codex | GPT-5 Pro |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 38.2 | 46.2 |
| Rank | 178 | 58 |
| Context | 400K | 400K |
| Input $/M | $1.25 | $15 |
| Output $/M | $10 | $120 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.7 (#107)
- GPT-5 Pro: 43.4 (#77)

| Benchmark | GPT-5.1-Codex | GPT-5 Pro |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| WeirdML | — | 60.4% |
| ALE-Bench | 1,245 | — |
| AlgoTune | — | 1.31 |

## Agentic & Tool Use

- GPT-5.1-Codex: 37.8 (#32)
- GPT-5 Pro: —

| Benchmark | GPT-5.1-Codex | GPT-5 Pro |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- GPT-5 Pro: 39.2 (#52)

| Benchmark | GPT-5.1-Codex | GPT-5 Pro |
|---|---|---|
| ARC-AGI-2 | — | 18.3% |
| SimpleBench | — | 61.6% |
| Kagi LLM Benchmark | — | 76.8% |
| ARC-AGI-1 | — | 70.2% |
| EnigmaEval | — | 18.8% |
| Epoch Capabilities Index | — | 150.26 |

## Math

- GPT-5.1-Codex: 29.3 (#218)
- GPT-5 Pro: 48.0 (#53)

| Benchmark | GPT-5.1-Codex | GPT-5 Pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 55.8% |
| FrontierMath Tier 4 | — | 19.5% |
| ProofBench | 9% | — |
| FrontierMath Tier 4 (v1) | — | 14.6% |

## Knowledge

- GPT-5.1-Codex: —
- GPT-5 Pro: 56.2 (#39)

| Benchmark | GPT-5.1-Codex | GPT-5 Pro |
|---|---|---|
| Humanity's Last Exam | — | 31.6% |

## FAQ

### Is GPT-5.1-Codex better than GPT-5 Pro?

GPT-5 Pro is the stronger model overall, scoring 46.2 to 38.2 on the Noometry Index. GPT-5.1-Codex costs 12× less per token, which makes it the better buy when GPT-5 Pro's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.1-Codex or GPT-5 Pro?

GPT-5.1-Codex is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; GPT-5 Pro lists at $15 and $120.

### Is GPT-5.1-Codex or GPT-5 Pro better for coding?

GPT-5 Pro scores higher on coding benchmarks: 43.4 versus 41.7 in the Noometry coding category.

### Which has the bigger context window?

Both accept 400K tokens.

### How many benchmarks do GPT-5.1-Codex and GPT-5 Pro share?

0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and GPT-5 Pro has 12.