Model comparison
GPT-5.3 Chat vs Kimi K3
Kimi K3 is the stronger model overall, scoring 59.5 to 42.8 on the Noometry Index.
Last verified . 18 shared benchmarks.
Summary
- They share 18 benchmarks with published results for both. GPT-5.3 Chat scores higher in 0 categories and Kimi K3 in 8 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Kimi K3 leads 74.2 to 38.2.
- GPT-5.3 Chat is cheaper at $1.75 / $14 per million input/output tokens, against $3 / $15 for Kimi K3.
- Kimi K3 accepts more context: 1.05M tokens versus 128K.
- Kimi K3 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Chat | Kimi K3 | |
|---|---|---|
| Provider | OpenAI | Moonshot AI |
| Noometry Index | 42.8 | 59.5 |
| Released | 2026-03-03 | 2026-07-16 |
| Weights | Proprietary | Open |
| Context window | 128K | 1.05M |
| Max output | 16K | 1.05M |
| Input $ / M tokens | $1.75 | $3 |
| Output $ / M tokens | $14 | $15 |
| Results tracked | 18 | 53 |
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Category by category
Coding Kimi K3 leads
GPT-5.3 Chat: 41.4 (#124), Kimi K3: 61.0 (#10)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Coding | 1408 | 1508 |
| DeepSWE | — | 68.5% |
| FrontierCode | — | 44.2% |
| LMArena WebDev | — | 1654 |
| FrontierSWE | — | 25.9% |
| SciCode | — | 59.5% |
| WeirdML | — | 82.6% |
| ALE-Bench | — | 1,524 |
Agentic & Tool Use Not comparable
GPT-5.3 Chat: —, Kimi K3: 41.8 (#20)
| Benchmark | GPT-5.3 Chat | 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 Kimi K3 leads
GPT-5.3 Chat: 28.5 (#102), Kimi K3: 63.0 (#17)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Hard Prompts | 1399 | 1496 |
| ARC-AGI-2 | — | 60.4% |
| SimpleBench | — | 60.7% |
| NYT Connections (extended) | — | 93.6% |
| ARC-AGI-1 | — | 94.5% |
| CritPt | — | 23.4% |
| Chess Puzzles | — | 39% |
| Mystery Game Puzzles | — | 26% |
| DTBench | — | 91.2% |
| LMCA | — | 52.7% |
| Surface Evolver Bench | — | 95% |
| Epoch Capabilities Index | — | 157.45 |
| ForecastBench | — | 61.1 |
Math Kimi K3 leads
GPT-5.3 Chat: 38.2 (#142), Kimi K3: 74.2 (#16)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Math | 1389 | 1491 |
| FrontierMath (Tiers 1-3) | — | 72.2% |
| FrontierMath Tier 4 | — | 39% |
| MathArena Final-Answer Competitions | — | 87.8% |
| OTIS Mock AIME 2024-2025 | — | 97.2% |
| ProofBench | — | 87% |
Knowledge Kimi K3 leads
GPT-5.3 Chat: 38.8 (#140), Kimi K3: 63.2 (#21)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Expert | 1397 | 1521 |
| GPQA Diamond | — | 93.1% |
| SimpleQA Verified | — | 50.6% |
Multimodal Not comparable
GPT-5.3 Chat: —, Kimi K3: 37.8 (#70)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| Blueprint-Bench 2 | — | 29.5% |
| Furniture Assembly | — | 34.2% |
Multilingual Kimi K3 leads
GPT-5.3 Chat: 50.3 (#124), Kimi K3: 56.3 (#21)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Non-English | 1382 | 1466 |
| LMArena Chinese | 1432 | 1529 |
| LMArena French | 1397 | 1491 |
| LMArena German | 1384 | 1488 |
| LMArena Japanese | 1352 | 1487 |
| LMArena Korean | 1346 | 1458 |
| LMArena Russian | 1400 | 1482 |
| LMArena Spanish | 1371 | 1472 |
Instruction Following Kimi K3 leads
GPT-5.3 Chat: 72.8 (#129), Kimi K3: 77.7 (#14)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Instruction Following | 1378 | 1483 |
Long Context Kimi K3 leads
GPT-5.3 Chat: 42.6 (#120), Kimi K3: 45.8 (#29)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Longer Query | 1396 | 1494 |
Writing & Preference Kimi K3 leads
GPT-5.3 Chat: 63.1 (#68), Kimi K3: 76.6 (#4)
| Benchmark | GPT-5.3 Chat | Kimi K3 |
|---|---|---|
| LMArena Text | 1389 | 1476 |
| LMArena Creative Writing | 1355 | 1454 |
| EQ-Bench Creative Writing | 1690 | 2082 |
| LMArena Multi-Turn | 1412 | 1488 |
| EQ-Bench 4 | — | 1339 |
Frequently asked questions
Is GPT-5.3 Chat better than Kimi K3?
Kimi K3 is the stronger model overall, scoring 59.5 to 42.8 on the Noometry Index.
Which is cheaper, GPT-5.3 Chat or Kimi K3?
GPT-5.3 Chat is cheaper. It lists at $1.75 per million input tokens and $14 per million output tokens; Kimi K3 lists at $3 and $15.
Is GPT-5.3 Chat or Kimi K3 better for coding?
Kimi K3 scores higher on coding benchmarks: 61.0 versus 41.4 in the Noometry coding category.
Which has the bigger context window?
Kimi K3 does, with 1.05M tokens against 128K.
How many benchmarks do GPT-5.3 Chat and Kimi K3 share?
18 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Kimi K3 has 53.