# GPT-5.5 Instant vs o3

> o3 is the stronger model overall, scoring 47.5 to 42.7 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-5-instant-vs-o3
- Last updated: 2026-10-11
- Shared benchmarks: 24

## Summary

- They share 24 benchmarks with published results for both. GPT-5.5 Instant scores higher in 2 categories and o3 in 7 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where o3 leads 50.2 to 26.5.
- The biggest single-benchmark swing is Chess Puzzles: 12% for GPT-5.5 Instant and 38% for o3.

## Snapshot

| | GPT-5.5 Instant | o3 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 42.7 | 47.5 |
| Rank | 110 | 61 |
| Context | — | 200K |
| Input $/M | — | $2 |
| Output $/M | — | $8 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.5 Instant: 44.3 (#74)
- o3: 46.8 (#64)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| LMArena Coding | 1433 | 1408 |
| SWE-bench Verified | — | 62.3% |
| SWE-bench Verified (bash only) | — | 58.4% |
| Aider Polyglot | — | 81.3% |
| SciCode | 48.6% | — |
| GSO | — | 8.8% |
| WeirdML | — | 52.4% |
| CadEval | — | 74% |
| ALE-Bench | — | 933.55 |

## Agentic & Tool Use

- GPT-5.5 Instant: —
- o3: 34.5 (#44)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 63% |
| GDPval | — | 30.8% |
| DeepResearch Bench | — | 45.2% |
| OSWorld | — | 23% |
| LMArena Search | — | 1144 |
| METR Time Horizons | — | 65.4% |

## Reasoning

- GPT-5.5 Instant: 24.9 (#155)
- o3: 32.0 (#78)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| CritPt | 0% | 1.4% |
| Chess Puzzles | 12% | 38% |
| LMArena Hard Prompts | 1426 | 1402 |
| Epoch Capabilities Index | 142.52 | 146.86 |
| ARC-AGI-2 | — | 6.5% |
| SimpleBench | — | 53.1% |
| Kagi LLM Benchmark | — | 67.6% |
| ARC-AGI-1 | — | 60.8% |
| EnigmaEval | — | 13.1% |
| Mystery Game Puzzles | — | 29% |
| DTBench | — | 84.8% |
| LMCA | — | 39.7% |
| ForecastBench | — | 62.5 |

## Math

- GPT-5.5 Instant: 26.5 (#259)
- o3: 50.2 (#58)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 26.3% | 33.3% |
| OTIS Mock AIME 2024-2025 | 68.1% | 84.4% |
| LMArena Math | 1420 | 1426 |
| FrontierMath Tier 4 | 2.4% | — |
| Omni-MATH | — | 71.4% |
| MATH Level 5 | — | 97.8% |
| FrontierMath (Feb 2025 set) | — | 18.7% |
| FrontierMath Tier 4 (v1) | — | 2.1% |

## Knowledge

- GPT-5.5 Instant: 48.9 (#74)
- o3: 54.6 (#52)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| GPQA Diamond | 82.5% | 81.8% |
| LMArena Expert | 1409 | 1402 |
| Humanity's Last Exam | — | 20.3% |
| SimpleQA Verified | — | 49.4% |
| MMLU-Pro | — | 85.9% |
| Confabulations | — | 14.4% |
| GPQA (HELM) | — | 75.3% |

## Multimodal

- GPT-5.5 Instant: 40.0 (#52)
- o3: 41.4 (#36)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| LMArena Vision | 1250 | 1214 |
| GeoBench | — | 74% |
| VPCT | — | 52% |
| LMArena Document | 1403 | — |

## Multilingual

- GPT-5.5 Instant: 52.8 (#80)
- o3: 51.7 (#105)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| LMArena Non-English | 1417 | 1401 |
| LMArena Chinese | 1456 | 1437 |
| LMArena French | 1428 | 1430 |
| LMArena German | 1411 | 1420 |
| LMArena Japanese | 1408 | 1403 |
| LMArena Korean | 1392 | 1370 |
| LMArena Russian | 1431 | 1406 |
| LMArena Spanish | 1429 | 1395 |

## Instruction Following

- GPT-5.5 Instant: 74.2 (#100)
- o3: 72.8 (#127)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| LMArena Instruction Following | 1406 | 1368 |
| IFEval | — | 86.9% |

## Long Context

- GPT-5.5 Instant: 43.4 (#96)
- o3: 53.3 (#6)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| LMArena Longer Query | 1422 | 1372 |
| Fiction.LiveBench | — | 88.9% |
| CL-bench | — | 17.8% |

## Writing & Preference

- GPT-5.5 Instant: 61.8 (#85)
- o3: 63.5 (#64)

| Benchmark | GPT-5.5 Instant | o3 |
|---|---|---|
| LMArena Text | 1419 | 1410 |
| LMArena Creative Writing | 1419 | 1359 |
| LMArena Multi-Turn | 1433 | 1405 |
| Short-Story Creative Writing | — | 83.9% |
| EQ-Bench Creative Writing | — | 1676 |
| WildBench | — | 86.1% |

## FAQ

### Is GPT-5.5 Instant better than o3?

o3 is the stronger model overall, scoring 47.5 to 42.7 on the Noometry Index.

### Is GPT-5.5 Instant or o3 better for coding?

o3 scores higher on coding benchmarks: 46.8 versus 44.3 in the Noometry coding category.

### How many benchmarks do GPT-5.5 Instant and o3 share?

24 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and o3 has 63.