Model comparison
GPT-5.5 Instant vs Kimi K2.5 Instant
GPT-5.5 Instant and Kimi K2.5 Instant score almost the same on the Noometry Index (42.7 vs 43.6), so choose on price, context window or the category you care about most.
Last verified . 17 shared benchmarks.
Summary
- They share 17 benchmarks with published results for both. GPT-5.5 Instant scores higher in 4 categories and Kimi K2.5 Instant in 5 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in math, where Kimi K2.5 Instant leads 39.4 to 26.5.
- Kimi K2.5 Instant has downloadable open weights; the other is API-only.
Side by side
| GPT-5.5 Instant | Kimi K2.5 Instant | |
|---|---|---|
| Provider | OpenAI | Moonshot AI |
| Noometry Index | 42.7 | 43.6 |
| Released | 2026-05-05 | — |
| Weights | Proprietary | Open |
| Context window | — | — |
| Max output | — | — |
| Input $ / M tokens | — | — |
| Output $ / M tokens | — | — |
| Results tracked | 27 | 18 |
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Category by category
Coding GPT-5.5 Instant leads
GPT-5.5 Instant: 44.3 (#74), Kimi K2.5 Instant: 42.6 (#97)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Coding | 1433 | 1484 |
| LMArena WebDev | — | 1404 |
| SciCode | 48.6% | — |
Reasoning Kimi K2.5 Instant leads
GPT-5.5 Instant: 24.9 (#155), Kimi K2.5 Instant: 29.7 (#90)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Hard Prompts | 1426 | 1443 |
| CritPt | 0% | — |
| Chess Puzzles | 12% | — |
| Epoch Capabilities Index | 142.52 | — |
Math Kimi K2.5 Instant leads
GPT-5.5 Instant: 26.5 (#259), Kimi K2.5 Instant: 39.4 (#105)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Math | 1420 | 1442 |
| FrontierMath (Tiers 1-3) | 26.3% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 68.1% | — |
Knowledge GPT-5.5 Instant leads
GPT-5.5 Instant: 48.9 (#74), Kimi K2.5 Instant: 40.2 (#123)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Expert | 1409 | 1440 |
| GPQA Diamond | 82.5% | — |
Multimodal Too close to call
GPT-5.5 Instant: 40.0 (#52), Kimi K2.5 Instant: 40.2 (#50)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Vision | 1250 | 1254 |
| LMArena Document | 1403 | — |
Multilingual Too close to call
GPT-5.5 Instant: 52.8 (#80), Kimi K2.5 Instant: 52.0 (#94)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Non-English | 1417 | 1406 |
| LMArena Chinese | 1456 | 1449 |
| LMArena French | 1428 | 1403 |
| LMArena German | 1411 | 1413 |
| LMArena Korean | 1392 | 1378 |
| LMArena Russian | 1431 | 1404 |
| LMArena Spanish | 1429 | 1447 |
| LMArena Japanese | 1408 | — |
Instruction Following Kimi K2.5 Instant leads
GPT-5.5 Instant: 74.2 (#100), Kimi K2.5 Instant: 75.3 (#65)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Instruction Following | 1406 | 1430 |
Long Context Too close to call
GPT-5.5 Instant: 43.4 (#96), Kimi K2.5 Instant: 43.9 (#83)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Longer Query | 1422 | 1435 |
Writing & Preference GPT-5.5 Instant leads
GPT-5.5 Instant: 61.8 (#85), Kimi K2.5 Instant: 60.6 (#95)
| Benchmark | GPT-5.5 Instant | Kimi K2.5 Instant |
|---|---|---|
| LMArena Text | 1419 | 1420 |
| LMArena Creative Writing | 1419 | 1381 |
| LMArena Multi-Turn | 1433 | 1427 |
Frequently asked questions
Is GPT-5.5 Instant better than Kimi K2.5 Instant?
GPT-5.5 Instant and Kimi K2.5 Instant score almost the same on the Noometry Index (42.7 vs 43.6), so choose on price, context window or the category you care about most.
Is GPT-5.5 Instant or Kimi K2.5 Instant better for coding?
GPT-5.5 Instant scores higher on coding benchmarks: 44.3 versus 42.6 in the Noometry coding category.
How many benchmarks do GPT-5.5 Instant and Kimi K2.5 Instant share?
17 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and Kimi K2.5 Instant has 18.