Model comparison
Mercury vs Step 5 Preview
Step 5 Preview is the stronger model overall, scoring 47.9 to 37.6 on the Noometry Index.
Last verified . 8 shared benchmarks.
StepFunSummary
- They share 8 benchmarks with published results for both. Mercury scores higher in 0 categories and Step 5 Preview in 6 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Step 5 Preview leads 40.0 to 17.5.
Side by side
| Mercury | Step 5 Preview | |
|---|---|---|
| Provider | Inception | StepFun |
| Noometry Index | 37.6 | 47.9 |
| Released | — | 2026-09-16 |
| Weights | Proprietary | Proprietary |
| Context window | — | 1.02M |
| Max output | — | 66K |
| Input $ / M tokens | — | $1 |
| Output $ / M tokens | — | $2.70 |
| Results tracked | 9 | 18 |
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Category by category
Coding Step 5 Preview leads
Mercury: 38.7 (#170), Step 5 Preview: 51.8 (#36)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Coding | 1322 | 1480 |
| LMArena WebDev | — | 1564 |
| SciCode | — | 58.9% |
Reasoning Step 5 Preview leads
Mercury: 17.5 (#293), Step 5 Preview: 40.0 (#57)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Hard Prompts | 1285 | 1465 |
| Kagi LLM Benchmark | 21.6% | — |
| CritPt | — | 20.9% |
Math Not comparable
Mercury: —, Step 5 Preview: 46.1 (#72)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| ProofBench | — | 42% |
| LMArena Math | — | 1470 |
Knowledge Not comparable
Mercury: —, Step 5 Preview: 41.2 (#112)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Expert | — | 1470 |
Multimodal Not comparable
Mercury: —, Step 5 Preview: 41.0 (#41)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Vision | — | 1267 |
Multilingual Step 5 Preview leads
Mercury: 41.6 (#206), Step 5 Preview: 53.8 (#54)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1260 | 1432 |
| LMArena Chinese | — | 1519 |
| LMArena Russian | — | 1436 |
| LMArena Spanish | — | 1439 |
Instruction Following Step 5 Preview leads
Mercury: 65.2 (#224), Step 5 Preview: 76.0 (#50)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1239 | 1444 |
Long Context Step 5 Preview leads
Mercury: 38.4 (#198), Step 5 Preview: 44.5 (#64)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1266 | 1455 |
Writing & Preference Step 5 Preview leads
Mercury: 46.2 (#221), Step 5 Preview: 62.8 (#71)
| Benchmark | Mercury | Step 5 Preview |
|---|---|---|
| LMArena Text | 1282 | 1442 |
| LMArena Creative Writing | 1191 | 1410 |
| LMArena Multi-Turn | 1282 | 1447 |
Frequently asked questions
Is Mercury better than Step 5 Preview?
Step 5 Preview is the stronger model overall, scoring 47.9 to 37.6 on the Noometry Index.
Is Mercury or Step 5 Preview better for coding?
Step 5 Preview scores higher on coding benchmarks: 51.8 versus 38.7 in the Noometry coding category.
How many benchmarks do Mercury and Step 5 Preview share?
8 benchmarks have published results for both models. Mercury has 9 scored results on Noometry and Step 5 Preview has 18.