# GPT-5.5 Pro vs GPT-5-Codex

> GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 37.3 on the Noometry Index. GPT-5-Codex costs 20× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.

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

## Summary

- The widest gap is in reasoning, where GPT-5.5 Pro leads 73.6 to 30.0.
- GPT-5-Codex is cheaper at $1.25 / $10 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 400K.

## Snapshot

| | GPT-5.5 Pro | GPT-5-Codex |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 64.3 | 37.3 |
| Rank | 7 | 190 |
| Context | 1.05M | 400K |
| Input $/M | $30 | $1.25 |
| Output $/M | $180 | $10 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.5 Pro: —
- GPT-5-Codex: 41.9 (#100)

| Benchmark | GPT-5.5 Pro | GPT-5-Codex |
|---|---|---|
| WeirdML | — | 54.5% |

## Agentic & Tool Use

- GPT-5.5 Pro: —
- GPT-5-Codex: 30.8 (#66)

| Benchmark | GPT-5.5 Pro | GPT-5-Codex |
|---|---|---|
| Terminal-Bench | — | 44.3% |

## Reasoning

- GPT-5.5 Pro: 73.6 (#7)
- GPT-5-Codex: 30.0 (#80)

| Benchmark | GPT-5.5 Pro | GPT-5-Codex |
|---|---|---|
| ARC-AGI-2 | 84.6% | — |
| SimpleBench | 76.9% | — |
| Kagi LLM Benchmark | — | 70.3% |
| ARC-AGI-1 | 96.5% | — |
| CritPt | 30.6% | — |
| Chess Puzzles | 64% | — |
| DTBench | 96% | — |
| LMCA | 53.9% | — |
| Epoch Capabilities Index | 162.45 | — |

## Math

- GPT-5.5 Pro: 83.8 (#8)
- GPT-5-Codex: —

| Benchmark | GPT-5.5 Pro | GPT-5-Codex |
|---|---|---|
| FrontierMath (Tiers 1-3) | 87.7% | — |
| FrontierMath Tier 4 | 78% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| FrontierMath (Feb 2025 set) | 52.4% | — |
| FrontierMath Tier 4 (v1) | 39.6% | — |

## Knowledge

- GPT-5.5 Pro: 64.2 (#17)
- GPT-5-Codex: —

| Benchmark | GPT-5.5 Pro | GPT-5-Codex |
|---|---|---|
| GPQA Diamond | 93.9% | — |

## FAQ

### Is GPT-5.5 Pro better than GPT-5-Codex?

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 37.3 on the Noometry Index. GPT-5-Codex costs 20× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.5 Pro or GPT-5-Codex?

GPT-5-Codex is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; GPT-5.5 Pro lists at $30 and $180.

### Which has the bigger context window?

GPT-5.5 Pro does, with 1.05M tokens against 400K.

### How many benchmarks do GPT-5.5 Pro and GPT-5-Codex share?

0 benchmarks have published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and GPT-5-Codex has 3.