Model comparison
GPT-5.4 nano vs Kimi K2 (Jul 2025)
GPT-5.4 nano and Kimi K2 (Jul 2025) score almost the same on the Noometry Index (41.9 vs 41.2), so choose on price, context window or the category you care about most.
Last verified . 25 shared benchmarks.
Summary
- They share 25 benchmarks with published results for both. GPT-5.4 nano scores higher in 5 categories and Kimi K2 (Jul 2025) in 3 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Kimi K2 (Jul 2025) leads 62.3 to 55.7.
- The biggest single-benchmark swing is Kagi LLM Benchmark: 39.7% for GPT-5.4 nano and 64.4% for Kimi K2 (Jul 2025).
- GPT-5.4 nano is cheaper at $0.20 / $1.25 per million input/output tokens, against $0.57 / $2.30 for Kimi K2 (Jul 2025).
- GPT-5.4 nano accepts more context: 400K tokens versus 262K.
- Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.
Side by side
| GPT-5.4 nano | Kimi K2 (Jul 2025) | |
|---|---|---|
| Provider | OpenAI | Moonshot AI |
| Noometry Index | 41.9 | 41.2 |
| Released | 2026-03-17 | 2025-07-12 |
| Weights | Proprietary | Open |
| Context window | 400K | 262K |
| Max output | 128K | 262K |
| Input $ / M tokens | $0.20 | $0.57 |
| Output $ / M tokens | $1.25 | $2.30 |
| Results tracked | 40 | 42 |
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Category by category
Coding GPT-5.4 nano leads
GPT-5.4 nano: 43.6 (#84), Kimi K2 (Jul 2025): 42.4 (#102)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| WeirdML | 49.2% | 42.8% |
| LMArena Coding | 1405 | 1399 |
| ALE-Bench | 1,005 | 597.5 |
| SWE-bench Verified (bash only) | — | 63.4% |
| Aider Polyglot | — | 59.1% |
| SciCode | 46.9% | — |
| GSO | — | 4.9% |
Agentic & Tool Use Not comparable
GPT-5.4 nano: —, Kimi K2 (Jul 2025): 32.4 (#64)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| Terminal-Bench | — | 35.7% |
| Berkeley Function Calling Leaderboard | — | 59.1% |
| METR Time Horizons | — | 59.2% |
Reasoning Too close to call
GPT-5.4 nano: 23.7 (#173), Kimi K2 (Jul 2025): 23.3 (#179)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| Kagi LLM Benchmark | 39.7% | 64.4% |
| LMArena Hard Prompts | 1381 | 1384 |
| Epoch Capabilities Index | 145.81 | 146.01 |
| ForecastBench | 57.3 | 60.2 |
| ARC-AGI-2 | 5.7% | — |
| SimpleBench | — | 26.3% |
| ARC-AGI-1 | 51.5% | — |
| CritPt | 9.3% | — |
| Chess Puzzles | 30% | — |
| Mystery Game Puzzles | 9% | — |
| DTBench | 80.3% | — |
| LMCA | 36.9% | — |
Math Kimi K2 (Jul 2025) leads
GPT-5.4 nano: 40.9 (#88), Kimi K2 (Jul 2025): 42.7 (#83)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Math | 1406 | 1397 |
| FrontierMath (Feb 2025 set) | 25.9% | 21.4% |
| FrontierMath Tier 4 (v1) | 6.3% | 0% |
| FrontierMath (Tiers 1-3) | 44.9% | — |
| FrontierMath Tier 4 | 12.2% | — |
| OTIS Mock AIME 2024-2025 | 87.8% | — |
| ProofBench | 5% | — |
| Omni-MATH | — | 65.4% |
Knowledge GPT-5.4 nano leads
GPT-5.4 nano: 41.9 (#103), Kimi K2 (Jul 2025): 37.3 (#157)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| Vectara Hallucination Rate | 3.1% | 17.9% |
| LMArena Expert | 1396 | 1365 |
| GPQA Diamond | 78.5% | — |
| SimpleQA Verified | 11.7% | — |
| MMLU-Pro | — | 81.9% |
| Confabulations | — | 20.4% |
| GPQA (HELM) | — | 65.3% |
Multimodal Not comparable
GPT-5.4 nano: 36.7 (#78), Kimi K2 (Jul 2025): —
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Vision | 1196 | — |
Multilingual Too close to call
GPT-5.4 nano: 48.6 (#140), Kimi K2 (Jul 2025): 49.6 (#130)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Non-English | 1359 | 1372 |
| LMArena Chinese | 1392 | 1415 |
| LMArena French | 1396 | 1379 |
| LMArena German | 1367 | 1387 |
| LMArena Japanese | 1343 | 1349 |
| LMArena Korean | 1320 | 1325 |
| LMArena Russian | 1363 | 1385 |
| LMArena Spanish | 1371 | 1386 |
Instruction Following Too close to call
GPT-5.4 nano: 71.9 (#144), Kimi K2 (Jul 2025): 71.1 (#156)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Instruction Following | 1362 | 1348 |
| IFEval | — | 85% |
Long Context Too close to call
GPT-5.4 nano: 41.6 (#137), Kimi K2 (Jul 2025): 41.2 (#145)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Longer Query | 1366 | 1353 |
| Fiction.LiveBench | — | 66.7% |
| CL-bench | — | 17.6% |
Writing & Preference Kimi K2 (Jul 2025) leads
GPT-5.4 nano: 55.7 (#142), Kimi K2 (Jul 2025): 62.3 (#78)
| Benchmark | GPT-5.4 nano | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Text | 1372 | 1380 |
| LMArena Creative Writing | 1314 | 1350 |
| LMArena Multi-Turn | 1382 | 1371 |
| Short-Story Creative Writing | — | 85.6% |
| EQ-Bench Creative Writing | — | 1666 |
| WildBench | — | 86.2% |
Frequently asked questions
Is GPT-5.4 nano better than Kimi K2 (Jul 2025)?
GPT-5.4 nano and Kimi K2 (Jul 2025) score almost the same on the Noometry Index (41.9 vs 41.2), so choose on price, context window or the category you care about most.
Which is cheaper, GPT-5.4 nano or Kimi K2 (Jul 2025)?
GPT-5.4 nano is cheaper. It lists at $0.20 per million input tokens and $1.25 per million output tokens; Kimi K2 (Jul 2025) lists at $0.57 and $2.30.
Is GPT-5.4 nano or Kimi K2 (Jul 2025) better for coding?
GPT-5.4 nano scores higher on coding benchmarks: 43.6 versus 42.4 in the Noometry coding category.
Which has the bigger context window?
GPT-5.4 nano does, with 400K tokens against 262K.
How many benchmarks do GPT-5.4 nano and Kimi K2 (Jul 2025) share?
25 benchmarks have published results for both models. GPT-5.4 nano has 40 scored results on Noometry and Kimi K2 (Jul 2025) has 42.