Model comparison
Mercury 2.5 vs Step 3.7 Flash
Step 3.7 Flash is the stronger model overall, scoring 37.3 to 33.5 on the Noometry Index. Mercury 2.5 costs 6.2× less per token, which makes it the better buy when Step 3.7 Flash's lead doesn't matter for your workload.
Last verified . 3 shared benchmarks.
StepFunSummary
- They share 3 benchmarks with published results for both. Mercury 2.5 scores higher in 1 category and Step 3.7 Flash in 2 categories; one gap is clear of the uncertainty.
- The widest gap is in math, where Step 3.7 Flash leads 42.9 to 23.3.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $0.18 / $1.11 for Step 3.7 Flash.
- Mercury 2.5 accepts more context: 260K tokens versus 256K.
- Step 3.7 Flash has downloadable open weights; the other is API-only.
Side by side
| Mercury 2.5 | Step 3.7 Flash | |
|---|---|---|
| Provider | Inception | StepFun |
| Noometry Index | 33.5 | 37.3 |
| Released | 2026-09-08 | 2026-05-29 |
| Weights | Proprietary | Open |
| Context window | 260K | 256K |
| Max output | 66K | 256K |
| Input $ / M tokens | $0.04 | $0.18 |
| Output $ / M tokens | $0.15 | $1.11 |
| Results tracked | 4 | 5 |
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Category by category
Coding Too close to call
Mercury 2.5: 39.5 (#156), Step 3.7 Flash: 40.0 (#150)
Reasoning Too close to call
Mercury 2.5: 22.4 (#193), Step 3.7 Flash: 21.6 (#219)
| Benchmark | Mercury 2.5 | Step 3.7 Flash |
|---|---|---|
| CritPt | 0% | 2.3% |
| NYT Connections (extended) | — | 39.7% |
Math Step 3.7 Flash leads
Mercury 2.5: 23.3 (#272), Step 3.7 Flash: 42.9 (#82)
| Benchmark | Mercury 2.5 | Step 3.7 Flash |
|---|---|---|
| MathArena Final-Answer Competitions | — | 68.5% |
| ProofBench | 3% | — |
Frequently asked questions
Is Mercury 2.5 better than Step 3.7 Flash?
Step 3.7 Flash is the stronger model overall, scoring 37.3 to 33.5 on the Noometry Index. Mercury 2.5 costs 6.2× less per token, which makes it the better buy when Step 3.7 Flash's lead doesn't matter for your workload.
Which is cheaper, Mercury 2.5 or Step 3.7 Flash?
Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; Step 3.7 Flash lists at $0.18 and $1.11.
Is Mercury 2.5 or Step 3.7 Flash better for coding?
They score almost the same on coding (39.5 vs 40.0); test both on your own repository before choosing.
Which has the bigger context window?
Mercury 2.5 does, with 260K tokens against 256K.
How many benchmarks do Mercury 2.5 and Step 3.7 Flash share?
3 benchmarks have published results for both models. Mercury 2.5 has 4 scored results on Noometry and Step 3.7 Flash has 5.