# GPT-5.3 Codex vs Kimi K2.6

> Side-by-side benchmark comparison for GPT-5.3 Codex and Kimi K2.6 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-3-codex-vs-kimi-2-6
- Last updated: October 10, 2026

- Shared sourced benchmarks: 9
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

GPT-5.3 Codex leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- GPT-5.3 Codex has the higher overall point estimate 60.85 to 58.74. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in agentic, where the averages are 55.5 for GPT-5.3 Codex and 43.7 for Kimi K2.6.
- The biggest single benchmark swing is Vibe Code Bench in Coding, with scores of 61.77% and 37.89%.
- Kimi K2.6 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 K2.6 |
|----------|----------|----------|
| Creator | OpenAI | Moonshot AI |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | 256K |
| Overall Score | 60.85 | 58.74 |
| Benchmarks Covered | 11 | 37 |
| Pricing (input/output) | $1.75 / $14.00 | $0.95 / $4.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 55.5 (Estimated · #35/123)
- Kimi K2.6 public-lane score: 43.7 (Supported · #57/123)

| Benchmark | GPT-5.3 Codex | Kimi K2.6 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 77.3% | 66.7% | GPT-5.3 Codex |
| OSWorld-Verified | 64.7% | 73.1% | Kimi K2.6 |
| Gert Labs | 57.47% | 56.82% | GPT-5.3 Codex |
| JobBench | 33.7% | Coming soon | Coming soon |
| BrowseComp | Coming soon | 83.2% | Coming soon |
| Toolathlon | Coming soon | 50% | Coming soon |
| MCP Atlas | Coming soon | 55.9% | Coming soon |
| Claw-Eval | Coming soon | 62.3% | Coming soon |
| DeepSearchQA | Coming soon | 92.5% | Coming soon |
| WideResearch | Coming soon | 80.8% | Coming soon |
| ResearchClawBench | Coming soon | 18.0% | Coming soon |
| OSWorld 2.0 | Coming soon | 4.6% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 53.6% | Coming soon |

### Coding

- Winner: GPT-5.3 Codex
- GPT-5.3 Codex public-lane score: 55.2 (Supported · #30/146)
- Kimi K2.6 public-lane score: 43.9 (Supported · #54/146)

| Benchmark | GPT-5.3 Codex | Kimi K2.6 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85% | 80.2% | GPT-5.3 Codex |
| SWE-bench Pro | 56.8% | 58.6% | Kimi K2.6 |
| SWE-Rebench | 58.2% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | 77.3% | 66.7% | GPT-5.3 Codex |
| Vibe Code Bench | 61.77% | 37.89% | GPT-5.3 Codex |
| LiveCodeBench (Vals) | 87.3% | 86.8% | GPT-5.3 Codex |
| SWE-bench (Vals) | 78.0% | 76.2% | GPT-5.3 Codex |
| LiveCodeBench v6 | Coming soon | 89.6% | Coming soon |
| SWE Multilingual | Coming soon | 76.7% | Coming soon |
| SciCode | Coming soon | 52.2% | Coming soon |
| cursorBench31 | Coming soon | 47.6% | Coming soon |

### Reasoning

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: 83.4 (Unranked · 2 rankable rows)
- Kimi K2.6 public-lane score: Coming soon

### Multimodal & Grounded

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: 80.1 (Unranked · 1 rankable row)
- Kimi K2.6 public-lane score: 73.8 (#27/54)

| Benchmark | GPT-5.3 Codex | Kimi K2.6 | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | Coming soon | 79.4% | Coming soon |
| MMMU-Pro w/ Python | Coming soon | 80.1% | Coming soon |
| CharXiv | Coming soon | 80.4% | Coming soon |
| MathVision | Coming soon | 87.4% | Coming soon |
| V* | Coming soon | 96.9% | Coming soon |

### Knowledge

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 65.7 (Estimated · #26/177)
- Kimi K2.6 public-lane score: 59.8 (Supported · #45/177)

| Benchmark | GPT-5.3 Codex | Kimi K2.6 | Winner |
|-----------|-----------|-----------|--------|
| GPQA | Coming soon | 90.5% | Coming soon |
| GPQA-D | Coming soon | 90.5% | Coming soon |
| HLE | Coming soon | 34.7% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 89.1% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 87.6% | Coming soon |

### Instruction Following

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: 92.6 (#18/127)
- Kimi K2.6 public-lane score: Coming soon

### Mathematics

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: Coming soon
- Kimi K2.6 public-lane score: 72.2 (#1/7)

| Benchmark | GPT-5.3 Codex | Kimi K2.6 | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | Coming soon | 96.4% | Coming soon |
| HMMT Feb 2026 | Coming soon | 92.7% | Coming soon |
| MMAnswerBench | Coming soon | 86.0% | Coming soon |
| FrontierMath v2 (Tiers 1-3) | Coming soon | 38.966% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 14.580% | Coming soon |

## FAQ

### Which is better overall, GPT-5.3 Codex or Kimi K2.6?

GPT-5.3 Codex has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### Where is the biggest gap between GPT-5.3 Codex and Kimi K2.6?

The widest category gap is in agentic, where the averages are 55.5 for GPT-5.3 Codex and 43.7 for Kimi K2.6.

### 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 K2.6 cover on BenchLM?

Kimi K2.6 currently has 37 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 K2.6 vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-spark-vs-kimi-2-6)
- [GPT-5.3 Codex vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gpt-5-3-codex)
- [Kimi K2.6 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-kimi-2-6)

## Explore More

- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [Kimi K2.6 profile](/models/kimi-2-6)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)