Model comparison
GPT-5.5 Pro vs Kimi K3
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 59.5 on the Noometry Index. Kimi K3 costs 11× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Last verified . 12 shared benchmarks.
Summary
- They share 12 benchmarks with published results for both. GPT-5.5 Pro scores higher in 3 categories and Kimi K3 in 0 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5.5 Pro leads 73.3 to 63.0.
- The biggest single-benchmark swing is FrontierMath Tier 4: 78% for GPT-5.5 Pro and 39% for Kimi K3.
- Kimi K3 is cheaper at $3 / $15 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 1.05M.
- Kimi K3 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.5 Pro | Kimi K3 | |
|---|---|---|
| Provider | OpenAI | Moonshot AI |
| Noometry Index | 64.3 | 59.5 |
| Released | 2026-04-23 | 2026-07-16 |
| Weights | Proprietary | Open |
| Context window | 1.05M | 1.05M |
| Max output | 128K | 1.05M |
| Input $ / M tokens | $30 | $3 |
| Output $ / M tokens | $180 | $15 |
| Results tracked | 14 | 53 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding Not comparable
GPT-5.5 Pro: —, Kimi K3: 61.0 (#10)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| DeepSWE | — | 68.5% |
| FrontierCode | — | 44.2% |
| LMArena WebDev | — | 1654 |
| FrontierSWE | — | 25.9% |
| SciCode | — | 59.5% |
| WeirdML | — | 82.6% |
| LMArena Coding | — | 1508 |
| ALE-Bench | — | 1,524 |
Agentic & Tool Use Not comparable
GPT-5.5 Pro: —, Kimi K3: 41.8 (#20)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| APEX-Agents | — | 50.6% |
| τ²-bench Banking | — | 37.1% |
| PostTrainBench | — | 32% |
| GBAEval | — | 48.3% |
| GDP.pdf | — | 19% |
| Vending-Bench 2 | — | 5,165 |
Reasoning GPT-5.5 Pro leads
GPT-5.5 Pro: 73.3 (#10), Kimi K3: 63.0 (#17)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| ARC-AGI-2 | 84.6% | 60.4% |
| SimpleBench | 76.9% | 60.7% |
| ARC-AGI-1 | 96.5% | 94.5% |
| CritPt | 30.6% | 23.4% |
| Chess Puzzles | 64% | 39% |
| DTBench | 96% | 91.2% |
| LMCA | 53.9% | 52.7% |
| Epoch Capabilities Index | 162.07 | 157.45 |
| NYT Connections (extended) | — | 93.6% |
| LMArena Hard Prompts | — | 1496 |
| Mystery Game Puzzles | — | 26% |
| Surface Evolver Bench | — | 95% |
| ForecastBench | — | 61.1 |
Math GPT-5.5 Pro leads
GPT-5.5 Pro: 84.0 (#10), Kimi K3: 74.2 (#16)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 87.7% | 72.2% |
| FrontierMath Tier 4 | 78% | 39% |
| OTIS Mock AIME 2024-2025 | 100% | 97.2% |
| MathArena Final-Answer Competitions | — | 87.8% |
| ProofBench | — | 87% |
| LMArena Math | — | 1491 |
| FrontierMath (Feb 2025 set) | 52.4% | — |
| FrontierMath Tier 4 (v1) | 39.6% | — |
Knowledge Too close to call
GPT-5.5 Pro: 64.1 (#19), Kimi K3: 63.2 (#21)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| GPQA Diamond | 93.9% | 93.1% |
| SimpleQA Verified | — | 50.6% |
| LMArena Expert | — | 1521 |
Multimodal Not comparable
GPT-5.5 Pro: —, Kimi K3: 37.8 (#70)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| Blueprint-Bench 2 | — | 29.5% |
| Furniture Assembly | — | 34.2% |
Multilingual Not comparable
GPT-5.5 Pro: —, Kimi K3: 56.3 (#21)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| LMArena Non-English | — | 1466 |
| LMArena Chinese | — | 1529 |
| LMArena French | — | 1491 |
| LMArena German | — | 1488 |
| LMArena Japanese | — | 1487 |
| LMArena Korean | — | 1458 |
| LMArena Russian | — | 1482 |
| LMArena Spanish | — | 1472 |
Instruction Following Not comparable
GPT-5.5 Pro: —, Kimi K3: 77.7 (#14)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| LMArena Instruction Following | — | 1483 |
Long Context Not comparable
GPT-5.5 Pro: —, Kimi K3: 45.8 (#29)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| LMArena Longer Query | — | 1494 |
Writing & Preference Not comparable
GPT-5.5 Pro: —, Kimi K3: 76.6 (#4)
| Benchmark | GPT-5.5 Pro | Kimi K3 |
|---|---|---|
| LMArena Text | — | 1476 |
| LMArena Creative Writing | — | 1454 |
| EQ-Bench Creative Writing | — | 2082 |
| EQ-Bench 4 | — | 1339 |
| LMArena Multi-Turn | — | 1488 |
Frequently asked questions
Is GPT-5.5 Pro better than Kimi K3?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 59.5 on the Noometry Index. Kimi K3 costs 11× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Which is cheaper, GPT-5.5 Pro or Kimi K3?
Kimi K3 is cheaper. It lists at $3 per million input tokens and $15 per million output tokens; GPT-5.5 Pro lists at $30 and $180.
Which has the bigger context window?
GPT-5.5 Pro does, with 1.05M tokens against 1.05M.
How many benchmarks do GPT-5.5 Pro and Kimi K3 share?
12 benchmarks have published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and Kimi K3 has 53.