# GPT-5.5 Instant vs o4-mini

> GPT-5.5 Instant and o4-mini score almost the same on the Noometry Index (42.5 vs 41.6), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/gpt-5-5-instant-vs-o4-mini
- Last updated: 2026-10-10
- Shared benchmarks: 25

## Summary

- They share 25 benchmarks with published results for both. GPT-5.5 Instant scores higher in 4 categories and o4-mini in 5 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in math, where o4-mini leads 40.2 to 26.1.
- The biggest single-benchmark swing is Chess Puzzles: 12% for GPT-5.5 Instant and 26% for o4-mini.

## Snapshot

| | GPT-5.5 Instant | o4-mini |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 42.5 | 41.6 |
| Rank | 99 | 119 |
| Context | — | 200K |
| Input $/M | — | $1.10 |
| Output $/M | — | $4.40 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.5 Instant: 43.7 (#73)
- o4-mini: 41.6 (#110)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| LMArena Coding | 1433 | 1369 |
| SWE-bench Verified (bash only) | — | 45% |
| Aider Polyglot | — | 72% |
| SciCode | 48.6% | — |
| GSO | — | 3.6% |
| WeirdML | — | 52.6% |
| CadEval | — | 62% |
| ALE-Bench | — | 826.17 |
| AlgoTune | — | 1.72 |

## Agentic & Tool Use

- GPT-5.5 Instant: —
- o4-mini: 32.3 (#57)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 53.2% |
| GDPval | — | 25.3% |
| METR Time Horizons | — | 63.9% |

## Reasoning

- GPT-5.5 Instant: 24.2 (#149)
- o4-mini: 24.6 (#143)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| CritPt | 0% | 0.6% |
| Chess Puzzles | 12% | 26% |
| LMArena Hard Prompts | 1426 | 1351 |
| Epoch Capabilities Index | 142.48 | 145.63 |
| ARC-AGI-2 | — | 6.1% |
| SimpleBench | — | 38.7% |
| Kagi LLM Benchmark | — | 67.6% |
| ARC-AGI-1 | — | 58.7% |
| EnigmaEval | — | 9.2% |
| Mystery Game Puzzles | — | 5% |
| DTBench | — | 77.6% |
| LMCA | — | 26.5% |
| ForecastBench | — | 61.8 |

## Math

- GPT-5.5 Instant: 26.1 (#241)
- o4-mini: 40.2 (#79)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| FrontierMath (Tiers 1-3) | 26.3% | 36.1% |
| FrontierMath Tier 4 | 2.4% | 4.9% |
| OTIS Mock AIME 2024-2025 | 68.1% | 81.7% |
| LMArena Math | 1420 | 1390 |
| Omni-MATH | — | 72% |
| MATH Level 5 | — | 97.8% |
| FrontierMath (Feb 2025 set) | — | 24.8% |
| FrontierMath Tier 4 (v1) | — | 6.3% |

## Knowledge

- GPT-5.5 Instant: 48.9 (#68)
- o4-mini: 43.5 (#83)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| GPQA Diamond | 82.5% | 79.6% |
| LMArena Expert | 1409 | 1344 |
| Humanity's Last Exam | — | 18.1% |
| SimpleQA Verified | — | 19.6% |
| MMLU-Pro | — | 82% |
| Confabulations | — | 15.8% |
| Vectara Hallucination Rate | — | 18.6% |
| GPQA (HELM) | — | 73.5% |

## Multimodal

- GPT-5.5 Instant: 39.3 (#48)
- o4-mini: 39.5 (#46)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| LMArena Vision | 1250 | 1194 |
| GeoBench | — | 64% |
| VPCT | — | 57.5% |
| LMArena Document | 1403 | — |

## Multilingual

- GPT-5.5 Instant: 53.0 (#76)
- o4-mini: 47.2 (#149)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| LMArena Non-English | 1417 | 1336 |
| LMArena Chinese | 1457 | 1355 |
| LMArena French | 1428 | 1362 |
| LMArena German | 1410 | 1336 |
| LMArena Japanese | 1408 | 1308 |
| LMArena Korean | 1393 | 1313 |
| LMArena Russian | 1430 | 1334 |
| LMArena Spanish | 1430 | 1346 |

## Instruction Following

- GPT-5.5 Instant: 74.4 (#94)
- o4-mini: 75.4 (#63)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| LMArena Instruction Following | 1407 | 1321 |
| IFEval | — | 92.8% |

## Long Context

- GPT-5.5 Instant: 43.4 (#92)
- o4-mini: 45.5 (#31)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| LMArena Longer Query | 1422 | 1315 |
| Fiction.LiveBench | — | 77.8% |

## Writing & Preference

- GPT-5.5 Instant: 62.0 (#81)
- o4-mini: 54.2 (#148)

| Benchmark | GPT-5.5 Instant | o4-mini |
|---|---|---|
| LMArena Text | 1419 | 1353 |
| LMArena Creative Writing | 1420 | 1294 |
| LMArena Multi-Turn | 1434 | 1350 |
| Short-Story Creative Writing | — | 75% |
| WildBench | — | 85.4% |

## FAQ

### Is GPT-5.5 Instant better than o4-mini?

GPT-5.5 Instant and o4-mini score almost the same on the Noometry Index (42.5 vs 41.6), so choose on price, context window or the category you care about most.

### Is GPT-5.5 Instant or o4-mini better for coding?

GPT-5.5 Instant scores higher on coding benchmarks: 43.7 versus 41.6 in the Noometry coding category.

### How many benchmarks do GPT-5.5 Instant and o4-mini share?

25 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and o4-mini has 60.