# Claude 2.1 vs GPT-5.3 Codex

> GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 25.2 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-2-1-vs-gpt-5-3-codex
- Last updated: 2026-10-11
- Shared benchmarks: 2

## Summary

- They share 2 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and GPT-5.3 Codex in 1 category; one gap is clear of the uncertainty.
- The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 26.2.
- The biggest single-benchmark swing is WeirdML: 7.1% for Claude 2.1 and 79.3% for GPT-5.3 Codex.

## Snapshot

| | Claude 2.1 | GPT-5.3 Codex |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 25.2 | 45.8 |
| Rank | 345 | 69 |
| Context | — | 400K |
| Input $/M | — | $1.75 |
| Output $/M | — | $14 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 26.2 (#327)
- GPT-5.3 Codex: 48.6 (#56)

| Benchmark | Claude 2.1 | GPT-5.3 Codex |
|---|---|---|
| WeirdML | 7.1% | 79.3% |
| SWE-bench Verified | — | 74.8% |
| LMArena WebDev | — | 1409 |
| ALE-Bench | — | 1,655 |

## Agentic & Tool Use

- Claude 2.1: —
- GPT-5.3 Codex: 48.0 (#9)

| Benchmark | Claude 2.1 | GPT-5.3 Codex |
|---|---|---|
| Terminal-Bench | — | 78.4% |
| METR Time Horizons | — | 74.5% |
| Vending-Bench 2 | — | 5,940 |

## Reasoning

- Claude 2.1: 21.4 (#221)
- GPT-5.3 Codex: —

| Benchmark | Claude 2.1 | GPT-5.3 Codex |
|---|---|---|
| Epoch Capabilities Index | 119.27 | 156.77 |
| DTBench | 51% | — |
| ForecastBench | 54.2 | — |

## Math

- Claude 2.1: 10.2 (#315)
- GPT-5.3 Codex: —

| Benchmark | Claude 2.1 | GPT-5.3 Codex |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | — |

## Knowledge

- Claude 2.1: 15.4 (#292)
- GPT-5.3 Codex: —

| Benchmark | Claude 2.1 | GPT-5.3 Codex |
|---|---|---|
| GPQA Diamond | 33% | — |
| MMLU | 73.5% | — |

## FAQ

### Is Claude 2.1 better than GPT-5.3 Codex?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 25.2 on the Noometry Index.

### Is Claude 2.1 or GPT-5.3 Codex better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 26.2 in the Noometry coding category.

### How many benchmarks do Claude 2.1 and GPT-5.3 Codex share?

2 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and GPT-5.3 Codex has 8.