# GPT-5.2-Codex vs o3

> Side-by-side benchmark comparison for GPT-5.2-Codex and o3 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-2-codex-vs-o3
- Last updated: October 17, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for GPT-5.2-Codex and o3.

## Summary

- GPT-5.2-Codex and o3 do not currently share a sourced benchmark row. The mirror therefore compares metadata, pricing, context windows, and each model's separately reported coverage without naming a benchmark winner.

## Model Snapshot

| Property | GPT-5.2-Codex | o3 |
|----------|----------|----------|
| Creator | OpenAI | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | 200K |
| Independent public score (not head-to-head) | 55.3 | 45.44 |
| Benchmarks Covered | 5 | 1 |
| Pricing (input/output) | $1.75 / $14.00 | $2.00 / $8.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.2-Codex public-lane score: 40.8 (Estimated · #64/128)
- o3 public-lane score: Coming soon

| Benchmark | GPT-5.2-Codex | o3 | Winner |
|-----------|-----------|-----------|--------|
| Gert Labs | 51.79% | Coming soon | Coming soon |
| JobBench | 26.0% | Coming soon | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.2-Codex public-lane score: 43.7 (Supported · #56/150)
- o3 public-lane score: Coming soon

| Benchmark | GPT-5.2-Codex | o3 | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 37.91% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 88.0% | Coming soon | Coming soon |
| SWE-bench (Vals) | 72.4% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.2-Codex public-lane score: 82.4 (Unranked · 2 rankable rows)
- o3 public-lane score: 77.2 (Unranked · 2 rankable rows)

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.2-Codex public-lane score: 76.9 (Unranked · 1 rankable row)
- o3 public-lane score: 67.8 (Unranked · 1 rankable row)

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.2-Codex public-lane score: 56.4 (Estimated · #54/184)
- o3 public-lane score: 48.6 (Estimated · #88/184)

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-5.2-Codex public-lane score: 93.8 (#4/148)
- o3 public-lane score: 87.4 (#38/148)

### Mathematics

- Winner: Insufficient shared evidence
- GPT-5.2-Codex public-lane score: Coming soon
- o3 public-lane score: 48.5 (Unranked · 1 rankable row)

| Benchmark | GPT-5.2-Codex | o3 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | Coming soon | 33.333% | Coming soon |

## FAQ

### Can I compare GPT-5.2-Codex and o3 on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but sourced benchmark coverage is still incomplete for a fair score-level comparison.

### Why does this page show "coming soon" values?

BenchLM only calls winners when public benchmark coverage is available on both sides of the comparison.

## Related Comparisons

- [GPT-5.2-Codex vs o3-pro](/compare/gpt-5-2-codex-vs-o3-pro)
- [o3 vs o3-pro](/compare/o3-vs-o3-pro)
- [GPT-5.2-Codex vs o3-mini](/compare/gpt-5-2-codex-vs-o3-mini)
- [o3 vs o3-mini](/compare/o3-vs-o3-mini)

## Explore More

- [GPT-5.2-Codex profile](/models/gpt-5-2-codex)
- [o3 profile](/models/o3)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)