# GPT-5.3 Codex vs Kimi K2.5

> Side-by-side benchmark comparison for GPT-5.3 Codex and Kimi K2.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-3-codex-vs-kimi-k2-5
- Last updated: October 17, 2026

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

## Quick Verdict

Pick GPT-5.3 Codex if you want the stronger benchmark profile. Kimi K2.5 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- GPT-5.3 Codex leads overall 60.48 to 53.05.
- The clearest category separation is in coding, where the averages are 53.5 for GPT-5.3 Codex and 38.5 for Kimi K2.5.
- The biggest single benchmark swing is Terminal-Bench 2.0 in Agentic, with scores of 77.3% and 50.8%.
- Kimi K2.5 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- GPT-5.3 Codex also has the larger context window at 400K.

## Model Snapshot

| Property | GPT-5.3 Codex | Kimi K2.5 |
|----------|----------|----------|
| Creator | OpenAI | Moonshot AI |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Non-Reasoning |
| Context | 400K | 256K |
| Overall Score | 60.48 | 53.05 |
| Benchmarks Covered | 11 | 68 |
| Pricing (input/output) | $1.75 / $14.00 | $0.60 / $3.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 55.5 (Estimated · #41/128)
- Kimi K2.5 public-lane score: 40.7 (Estimated · #66/128)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 77.3% | 50.8% | GPT-5.3 Codex |
| OSWorld-Verified | 64.7% | 63.3% | GPT-5.3 Codex |
| Gert Labs | 57.47% | 45.88% | GPT-5.3 Codex |
| JobBench | 33.7% | 8.7% | GPT-5.3 Codex |
| BrowseComp | Coming soon | 60.6% | Coming soon |
| Claw-Eval | Coming soon | 52.3% | Coming soon |
| QwenClawBench | Coming soon | 54.3% | Coming soon |
| τ³-bench results | Coming soon | 65.7% | Coming soon |
| DeepSearchQA | Coming soon | 77.1% | Coming soon |
| DeepPlanning | Coming soon | 14.4% | Coming soon |
| Toolathlon | Coming soon | 27.8% | Coming soon |
| MCP Atlas | Coming soon | 29.5% | Coming soon |
| MCP-Tasks | Coming soon | 59.1% | Coming soon |
| WideResearch | Coming soon | 72.7% | Coming soon |
| BFCL v4 | Coming soon | 68.3% | Coming soon |
| ResearchClawBench | Coming soon | 14.0% | Coming soon |

### Coding

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 53.5 (Supported · #35/150)
- Kimi K2.5 public-lane score: 38.5 (Estimated · #68/150)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85% | 76.8% | GPT-5.3 Codex |
| SWE-bench Pro | 56.8% | 50.7% | GPT-5.3 Codex |
| SWE-Rebench | 58.2% | 58.5% | Kimi K2.5 |
| Terminal-Bench 2.0 | 77.3% | 50.8% | GPT-5.3 Codex |
| Vibe Code Bench | 61.77% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 87.3% | Coming soon | Coming soon |
| SWE-bench (Vals) | 78.0% | Coming soon | Coming soon |
| SWE-bench Verified* | Coming soon | 70.8% | Coming soon |
| LiveCodeBench v6 | Coming soon | 85.0% | Coming soon |
| SWE Multilingual | Coming soon | 73% | Coming soon |
| React Native Evals | Coming soon | 77.2% | Coming soon |
| NL2Repo | Coming soon | 32% | Coming soon |
| SciCode | Coming soon | 48.7% | Coming soon |

### Reasoning

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: 83.1 (Unranked · 2 rankable rows)
- Kimi K2.5 public-lane score: 72.2 (Unranked · 3 rankable rows)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| LongBench v2 | Coming soon | 61% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: 80.1 (Unranked · 1 rankable row)
- Kimi K2.5 public-lane score: 70.4 (#32/54)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| MMMU | Coming soon | 84.3% | Coming soon |
| MMMU-Pro | Coming soon | 78.5% | Coming soon |
| RealWorldQA | Coming soon | 81.0% | Coming soon |
| OmniDocBench 1.5 | Coming soon | 88.8% | Coming soon |
| Video-MME | Coming soon | 87.4% | Coming soon |
| Video-MME (with subtitle) | Coming soon | 87.4% | Coming soon |
| Video-MME (w/o subtitle) | Coming soon | 83.2% | Coming soon |
| MathVision | Coming soon | 84.2% | Coming soon |
| We-Math | Coming soon | 84.7% | Coming soon |
| DynaMath | Coming soon | 84.4% | Coming soon |
| SimpleVQA | Coming soon | 71.2% | Coming soon |
| MMLongBench-Doc | Coming soon | 58.5% | Coming soon |
| CC-OCR | Coming soon | 79.7% | Coming soon |
| AI2D_TEST | Coming soon | 90.8% | Coming soon |
| CountBench | Coming soon | 94.1% | Coming soon |
| RefCOCO (avg) | Coming soon | 87.8% | Coming soon |
| MMVU | Coming soon | 80.4% | Coming soon |
| VideoMMMU | Coming soon | 86.6% | Coming soon |
| MLVU (M-Avg) | Coming soon | 85.0% | Coming soon |
| CharXiv | Coming soon | 77.5% | Coming soon |

### Knowledge

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 65.4 (Estimated · #33/184)
- Kimi K2.5 public-lane score: 51.4 (Estimated · #75/184)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| GPQA | Coming soon | 87.6% | Coming soon |
| GPQA-D | Coming soon | 87.6% | Coming soon |
| SuperGPQA | Coming soon | 69.2% | Coming soon |
| MMLU-Pro | Coming soon | 87.1% | Coming soon |
| MMLU-Pro (Arcee) | Coming soon | 87.1% | Coming soon |
| MMLU-Redux | Coming soon | 94.5% | Coming soon |
| C-Eval | Coming soon | 94% | Coming soon |
| HLE | Coming soon | 30.1% | Coming soon |

### Multilingual

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: Coming soon
- Kimi K2.5 public-lane score: 87.3 (#8/17)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| MMLU-ProX | Coming soon | 82.3% | Coming soon |
| NOVA-63 | Coming soon | 56.0% | Coming soon |
| INCLUDE | Coming soon | 83.3% | Coming soon |
| PolyMath | Coming soon | 43.1% | Coming soon |
| MAXIFE | Coming soon | 72.8% | Coming soon |

### Instruction Following

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 92.6 (#18/148)
- Kimi K2.5 public-lane score: 85.8 (#48/148)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| IFEval | Coming soon | 93.9% | Coming soon |

### Mathematics

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: Coming soon
- Kimi K2.5 public-lane score: 83.3 (Unranked · 7 rankable rows)

| Benchmark | GPT-5.3 Codex | Kimi K2.5 | Winner |
|-----------|-----------|-----------|--------|
| AIME 2025 | Coming soon | 96.1% | Coming soon |
| AIME26 | Coming soon | 95.8% | Coming soon |
| AIME25 (Arcee) | Coming soon | 96.3% | Coming soon |
| HMMT Feb 2025 | Coming soon | 95.4% | Coming soon |
| HMMT Nov 2025 | Coming soon | 91.1% | Coming soon |
| HMMT Feb 2026 | Coming soon | 87.1% | Coming soon |
| MMAnswerBench | Coming soon | 81.8% | Coming soon |

## FAQ

### Which is better overall, GPT-5.3 Codex or Kimi K2.5?

GPT-5.3 Codex is ahead overall on BenchLM right now.

### Where is the biggest gap between GPT-5.3 Codex and Kimi K2.5?

The widest category gap is in coding, where the averages are 53.5 for GPT-5.3 Codex and 38.5 for Kimi K2.5.

### How many benchmarks does GPT-5.3 Codex cover on BenchLM?

GPT-5.3 Codex currently has 11 sourced benchmark scores on BenchLM.

### How many benchmarks does Kimi K2.5 cover on BenchLM?

Kimi K2.5 currently has 68 sourced benchmark scores on BenchLM.

## Related Comparisons

- [GPT-5.3 Codex vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-vs-gpt-5-3-codex-spark)
- [Kimi K2.5 vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-spark-vs-kimi-k2-5)
- [GPT-5.3 Codex vs Kimi K2.5 (Reasoning)](/compare/gpt-5-3-codex-vs-kimi-k2-5-reasoning)
- [Kimi K2.5 vs Kimi K2.5 (Reasoning)](/compare/kimi-k2-5-vs-kimi-k2-5-reasoning)

## Explore More

- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [Kimi K2.5 profile](/models/kimi-k2-5)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)