Model comparison
Mercury 2.5 vs Step 5 Preview
Step 5 Preview has enough public results to be ranked (#78); Mercury 2.5 does not yet, so treat this comparison as directional.
Last verified . 0 shared benchmarks.
StepFunSummary
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $1 / $2.70 for Step 5 Preview.
- Step 5 Preview accepts more context: 1.02M tokens versus 260K.
Side by side
| Mercury 2.5 | Step 5 Preview | |
|---|---|---|
| Provider | Inception | StepFun |
| Noometry Index | 30.2 | 43.8 |
| Released | 2026-09-08 | 2026-09-16 |
| Weights | Proprietary | Proprietary |
| Context window | 260K | 1.02M |
| Max output | 66K | 66K |
| Input $ / M tokens | $0.04 | $1 |
| Output $ / M tokens | $0.15 | $2.70 |
| Results tracked | 2 | 3 |
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Category by category
Coding Not comparable
Mercury 2.5: —, Step 5 Preview: 50.6 (#40)
| Benchmark | Mercury 2.5 | Step 5 Preview |
|---|---|---|
| LMArena WebDev | — | 1569 |
| SciCode | — | 58.9% |
| ALE-Bench | 301.65 | — |
Reasoning Not comparable
Mercury 2.5: —, Step 5 Preview: 38.0 (#58)
| Benchmark | Mercury 2.5 | Step 5 Preview |
|---|---|---|
| CritPt | — | 20.9% |
Math Not comparable
Mercury 2.5: 22.4, Step 5 Preview: —
| Benchmark | Mercury 2.5 | Step 5 Preview |
|---|---|---|
| ProofBench | 3% | — |
Frequently asked questions
Is Mercury 2.5 better than Step 5 Preview?
Step 5 Preview has enough public results to be ranked (#78); Mercury 2.5 does not yet, so treat this comparison as directional.
Which is cheaper, Mercury 2.5 or Step 5 Preview?
Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; Step 5 Preview lists at $1 and $2.70.
Which has the bigger context window?
Step 5 Preview does, with 1.02M tokens against 260K.
How many benchmarks do Mercury 2.5 and Step 5 Preview share?
0 benchmarks have published results for both models. Mercury 2.5 has 2 scored results on Noometry and Step 5 Preview has 3.