# GPT-5.5 Instant vs Step 5 Preview

> Step 5 Preview is the stronger model overall, scoring 43.8 to 42.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-5-instant-vs-step-5-preview
- Last updated: 2026-10-10
- Shared benchmarks: 2

## Summary

- They share 2 benchmarks with published results for both. GPT-5.5 Instant scores higher in 0 categories and Step 5 Preview in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Step 5 Preview leads 38.0 to 24.2.
- The biggest single-benchmark swing is CritPt: 0% for GPT-5.5 Instant and 20.9% for Step 5 Preview.

## Snapshot

| | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 42.5 | 43.8 |
| Rank | 99 | 78 |
| Context | — | 1.02M |
| Input $/M | — | $1 |
| Output $/M | — | $2.70 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.5 Instant: 43.7 (#73)
- Step 5 Preview: 50.6 (#40)

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| SciCode | 48.6% | 58.9% |
| LMArena WebDev | — | 1569 |
| LMArena Coding | 1433 | — |

## Reasoning

- GPT-5.5 Instant: 24.2 (#149)
- Step 5 Preview: 38.0 (#58)

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| CritPt | 0% | 20.9% |
| Chess Puzzles | 12% | — |
| LMArena Hard Prompts | 1426 | — |
| Epoch Capabilities Index | 142.48 | — |

## Math

- GPT-5.5 Instant: 26.1 (#241)
- Step 5 Preview: —

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| FrontierMath (Tiers 1-3) | 26.3% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 68.1% | — |
| LMArena Math | 1420 | — |

## Knowledge

- GPT-5.5 Instant: 48.9 (#68)
- Step 5 Preview: —

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| GPQA Diamond | 82.5% | — |
| LMArena Expert | 1409 | — |

## Multimodal

- GPT-5.5 Instant: 39.3 (#48)
- Step 5 Preview: —

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| LMArena Vision | 1250 | — |
| LMArena Document | 1403 | — |

## Multilingual

- GPT-5.5 Instant: 53.0 (#76)
- Step 5 Preview: —

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1417 | — |
| LMArena Chinese | 1457 | — |
| LMArena French | 1428 | — |
| LMArena German | 1410 | — |
| LMArena Japanese | 1408 | — |
| LMArena Korean | 1393 | — |
| LMArena Russian | 1430 | — |
| LMArena Spanish | 1430 | — |

## Instruction Following

- GPT-5.5 Instant: 74.4 (#94)
- Step 5 Preview: —

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1407 | — |

## Long Context

- GPT-5.5 Instant: 43.4 (#92)
- Step 5 Preview: —

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1422 | — |

## Writing & Preference

- GPT-5.5 Instant: 62.0 (#81)
- Step 5 Preview: —

| Benchmark | GPT-5.5 Instant | Step 5 Preview |
|---|---|---|
| LMArena Text | 1419 | — |
| LMArena Creative Writing | 1420 | — |
| LMArena Multi-Turn | 1434 | — |

## FAQ

### Is GPT-5.5 Instant better than Step 5 Preview?

Step 5 Preview is the stronger model overall, scoring 43.8 to 42.5 on the Noometry Index.

### Is GPT-5.5 Instant or Step 5 Preview better for coding?

Step 5 Preview scores higher on coding benchmarks: 50.6 versus 43.7 in the Noometry coding category.

### How many benchmarks do GPT-5.5 Instant and Step 5 Preview share?

2 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and Step 5 Preview has 3.