Model comparison
GPT-5.5 Instant vs o3-mini
GPT-5.5 Instant is the stronger model overall, scoring 42.7 to 36.7 on the Noometry Index.
Last verified . 25 shared benchmarks.
Summary
- They share 25 benchmarks with published results for both. GPT-5.5 Instant scores higher in 6 categories and o3-mini in 2 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where GPT-5.5 Instant leads 61.8 to 50.3.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 68.1% for GPT-5.5 Instant and 76.9% for o3-mini.
Side by side
| GPT-5.5 Instant | o3-mini | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 42.7 | 36.7 |
| Released | 2026-05-05 | 2024-12-20 |
| Weights | Proprietary | Proprietary |
| Context window | — | 200K |
| Max output | — | 100K |
| Input $ / M tokens | — | $1.10 |
| Output $ / M tokens | — | $4.40 |
| Results tracked | 27 | 51 |
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Category by category
Coding GPT-5.5 Instant leads
GPT-5.5 Instant: 44.3 (#74), o3-mini: 40.8 (#132)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| SciCode | 48.6% | 39.8% |
| LMArena Coding | 1433 | 1378 |
| Aider Polyglot | — | 60.4% |
| GSO | — | 1.3% |
| WeirdML | — | 43.7% |
| LiveBench Coding | — | 82.7% |
| CadEval | — | 54% |
Agentic & Tool Use Not comparable
GPT-5.5 Instant: —, o3-mini: 29.6 (#84)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| Cybench | — | 22.5% |
Reasoning GPT-5.5 Instant leads
GPT-5.5 Instant: 24.9 (#155), o3-mini: 16.3 (#305)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| CritPt | 0% | 0.3% |
| Chess Puzzles | 12% | 17% |
| LMArena Hard Prompts | 1426 | 1366 |
| Epoch Capabilities Index | 142.52 | 140.34 |
| ARC-AGI-2 | — | 3% |
| SimpleBench | — | 22.8% |
| ARC-AGI-1 | — | 34.5% |
| LiveBench Reasoning | — | 89.6% |
| Mystery Game Puzzles | — | 7% |
| DTBench | — | 68.8% |
| LiveBench Data Analysis | — | 70.6% |
| LMCA | — | 19% |
| ForecastBench | — | 59.6 |
| LiveBench | — | 75.9% |
Math o3-mini leads
GPT-5.5 Instant: 26.5 (#259), o3-mini: 28.1 (#244)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| FrontierMath (Tiers 1-3) | 26.3% | 18.6% |
| FrontierMath Tier 4 | 2.4% | 0% |
| OTIS Mock AIME 2024-2025 | 68.1% | 76.9% |
| LMArena Math | 1420 | 1396 |
| LiveBench Math | — | 77.3% |
| MATH Level 5 | — | 96.5% |
| FrontierMath (Feb 2025 set) | — | 12.4% |
| FrontierMath Tier 4 (v1) | — | 4.2% |
Knowledge GPT-5.5 Instant leads
GPT-5.5 Instant: 48.9 (#74), o3-mini: 38.3 (#146)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| GPQA Diamond | 82.5% | 77% |
| LMArena Expert | 1409 | 1364 |
| SimpleQA Verified | — | 15.3% |
| Confabulations | — | 17.9% |
Multimodal Not comparable
GPT-5.5 Instant: 40.0 (#52), o3-mini: —
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| LMArena Vision | 1250 | — |
| LMArena Document | 1403 | — |
Multilingual GPT-5.5 Instant leads
GPT-5.5 Instant: 52.8 (#80), o3-mini: 45.7 (#164)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| LMArena Non-English | 1417 | 1319 |
| LMArena Chinese | 1456 | 1379 |
| LMArena French | 1428 | 1334 |
| LMArena German | 1411 | 1303 |
| LMArena Japanese | 1408 | 1286 |
| LMArena Korean | 1392 | 1314 |
| LMArena Russian | 1431 | 1304 |
| LMArena Spanish | 1429 | 1321 |
Instruction Following Too close to call
GPT-5.5 Instant: 74.2 (#100), o3-mini: 75.1 (#72)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| LMArena Instruction Following | 1406 | 1337 |
| LiveBench Instruction Following | — | 84.4% |
Long Context GPT-5.5 Instant leads
GPT-5.5 Instant: 43.4 (#96), o3-mini: 33.8 (#256)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| LMArena Longer Query | 1422 | 1343 |
| Fiction.LiveBench | — | 50% |
Writing & Preference GPT-5.5 Instant leads
GPT-5.5 Instant: 61.8 (#85), o3-mini: 50.3 (#182)
| Benchmark | GPT-5.5 Instant | o3-mini |
|---|---|---|
| LMArena Text | 1419 | 1337 |
| LMArena Creative Writing | 1419 | 1286 |
| LMArena Multi-Turn | 1433 | 1320 |
| Short-Story Creative Writing | — | 61.7% |
| LiveBench Language | — | 50.7% |
Frequently asked questions
Is GPT-5.5 Instant better than o3-mini?
GPT-5.5 Instant is the stronger model overall, scoring 42.7 to 36.7 on the Noometry Index.
Is GPT-5.5 Instant or o3-mini better for coding?
GPT-5.5 Instant scores higher on coding benchmarks: 44.3 versus 40.8 in the Noometry coding category.
How many benchmarks do GPT-5.5 Instant and o3-mini share?
25 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and o3-mini has 51.