# Mercury 2 vs Step 5 Preview

> Step 5 Preview is the stronger model overall, scoring 43.8 to 38.8 on the Noometry Index. Mercury 2 costs 3.8× less per token, which makes it the better buy when Step 5 Preview's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/mercury-2-vs-step-5-preview
- Last updated: 2026-10-10
- Shared benchmarks: 3

## Summary

- They share 3 benchmarks with published results for both. Mercury 2 scores higher in 0 categories and Step 5 Preview in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in coding, where Step 5 Preview leads 50.6 to 33.2.
- The biggest single-benchmark swing is SciCode: 38.7% for Mercury 2 and 58.9% for Step 5 Preview.
- Mercury 2 is cheaper at $0.25 / $0.75 per million input/output tokens, against $1 / $2.70 for Step 5 Preview.
- Step 5 Preview accepts more context: 1.02M tokens versus 128K.

## Snapshot

| | Mercury 2 | Step 5 Preview |
|---|---|---|
| Provider | Inception | StepFun |
| Noometry Index | 38.8 | 43.8 |
| Rank | 167 | 78 |
| Context | 128K | 1.02M |
| Input $/M | $0.25 | $1 |
| Output $/M | $0.75 | $2.70 |
| Weights | Proprietary | Proprietary |

## Coding

- Mercury 2: 33.2 (#250)
- Step 5 Preview: 50.6 (#40)

| Benchmark | Mercury 2 | Step 5 Preview |
|---|---|---|
| LMArena WebDev | 1170 | 1569 |
| SciCode | 38.7% | 58.9% |
| WeirdML | 43.2% | — |
| LMArena Coding | 1391 | — |
| ALE-Bench | 785.58 | — |

## Reasoning

- Mercury 2: 23.0 (#170)
- Step 5 Preview: 38.0 (#58)

| Benchmark | Mercury 2 | Step 5 Preview |
|---|---|---|
| CritPt | 0.8% | 20.9% |
| LMArena Hard Prompts | 1362 | — |

## Knowledge

- Mercury 2: 35.6 (#170)
- Step 5 Preview: —

| Benchmark | Mercury 2 | Step 5 Preview |
|---|---|---|
| Vectara Hallucination Rate | 12.3% | — |
| LMArena Expert | 1358 | — |

## Multilingual

- Mercury 2: 46.8 (#153)
- Step 5 Preview: —

| Benchmark | Mercury 2 | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1331 | — |
| LMArena Chinese | 1416 | — |
| LMArena Russian | 1303 | — |

## Instruction Following

- Mercury 2: 70.4 (#161)
- Step 5 Preview: —

| Benchmark | Mercury 2 | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1328 | — |

## Long Context

- Mercury 2: 40.4 (#149)
- Step 5 Preview: —

| Benchmark | Mercury 2 | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1329 | — |

## Writing & Preference

- Mercury 2: 54.0 (#151)
- Step 5 Preview: —

| Benchmark | Mercury 2 | Step 5 Preview |
|---|---|---|
| LMArena Text | 1355 | — |
| LMArena Creative Writing | 1289 | — |
| LMArena Multi-Turn | 1358 | — |

## FAQ

### Is Mercury 2 better than Step 5 Preview?

Step 5 Preview is the stronger model overall, scoring 43.8 to 38.8 on the Noometry Index. Mercury 2 costs 3.8× less per token, which makes it the better buy when Step 5 Preview's lead doesn't matter for your workload.

### Which is cheaper, Mercury 2 or Step 5 Preview?

Mercury 2 is cheaper. It lists at $0.25 per million input tokens and $0.75 per million output tokens; Step 5 Preview lists at $1 and $2.70.

### Is Mercury 2 or Step 5 Preview better for coding?

Step 5 Preview scores higher on coding benchmarks: 50.6 versus 33.2 in the Noometry coding category.

### Which has the bigger context window?

Step 5 Preview does, with 1.02M tokens against 128K.

### How many benchmarks do Mercury 2 and Step 5 Preview share?

3 benchmarks have published results for both models. Mercury 2 has 17 scored results on Noometry and Step 5 Preview has 3.