Model comparison
Mercury 2.5 vs Qwen3.5 27B
Qwen3.5 27B is the stronger model overall, scoring 41.9 to 33.5 on the Noometry Index. Mercury 2.5 costs 12× less per token, which makes it the better buy when Qwen3.5 27B's lead doesn't matter for your workload.
Last verified . 1 shared benchmarks.
Alibaba (Qwen)Summary
- They share 1 benchmark with published results for both. Mercury 2.5 scores higher in 1 category and Qwen3.5 27B in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in math, where Qwen3.5 27B leads 38.8 to 23.3.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $0.30 / $2.40 for Qwen3.5 27B.
- Qwen3.5 27B accepts more context: 262K tokens versus 260K.
- Qwen3.5 27B has downloadable open weights; the other is API-only.
Side by side
| Mercury 2.5 | Qwen3.5 27B | |
|---|---|---|
| Provider | Inception | Alibaba (Qwen) |
| Noometry Index | 33.5 | 41.9 |
| Released | 2026-09-08 | 2026-02-23 |
| Weights | Proprietary | Open |
| Context window | 260K | 262K |
| Max output | 66K | 66K |
| Input $ / M tokens | $0.04 | $0.30 |
| Output $ / M tokens | $0.15 | $2.40 |
| Results tracked | 4 | 28 |
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Category by category
Coding Too close to call
Mercury 2.5: 39.5 (#156), Qwen3.5 27B: 38.9 (#168)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| ALE-Bench | 301.65 | 349.45 |
| LMArena WebDev | — | 1358 |
| SciCode | 38.5% | — |
| WeirdML | — | 39.5% |
| LMArena Coding | — | 1427 |
Agentic & Tool Use Not comparable
Mercury 2.5: —, Qwen3.5 27B: —
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| Vending-Bench 2 | — | 201.98 |
Reasoning Qwen3.5 27B leads
Mercury 2.5: 22.4 (#193), Qwen3.5 27B: 27.5 (#117)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| NYT Connections (extended) | — | 47.9% |
| CritPt | 0% | — |
| Thematic Generalization | — | 45.5% |
| LMArena Hard Prompts | — | 1414 |
| DTBench | — | 82.4% |
| LMCA | — | 34% |
Math Qwen3.5 27B leads
Mercury 2.5: 23.3 (#272), Qwen3.5 27B: 38.8 (#127)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| MathArena Final-Answer Competitions | — | 56.7% |
| ProofBench | 3% | — |
| LMArena Math | — | 1429 |
Knowledge Not comparable
Mercury 2.5: —, Qwen3.5 27B: 38.0 (#150)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| Vectara Hallucination Rate | — | 12.1% |
| LMArena Expert | — | 1428 |
Multimodal Not comparable
Mercury 2.5: —, Qwen3.5 27B: 39.4 (#59)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| LMArena Vision | — | 1241 |
Multilingual Not comparable
Mercury 2.5: —, Qwen3.5 27B: 50.8 (#115)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| LMArena Non-English | — | 1390 |
| LMArena Chinese | — | 1478 |
| LMArena French | — | 1410 |
| LMArena German | — | 1393 |
| LMArena Japanese | — | 1345 |
| LMArena Korean | — | 1358 |
| LMArena Russian | — | 1390 |
| LMArena Spanish | — | 1407 |
Instruction Following Not comparable
Mercury 2.5: —, Qwen3.5 27B: 73.5 (#119)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| LMArena Instruction Following | — | 1393 |
Long Context Not comparable
Mercury 2.5: —, Qwen3.5 27B: 43.1 (#106)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| LMArena Longer Query | — | 1413 |
Writing & Preference Not comparable
Mercury 2.5: —, Qwen3.5 27B: 59.3 (#111)
| Benchmark | Mercury 2.5 | Qwen3.5 27B |
|---|---|---|
| LMArena Text | — | 1409 |
| LMArena Creative Writing | — | 1362 |
| LMArena Multi-Turn | — | 1410 |
Frequently asked questions
Is Mercury 2.5 better than Qwen3.5 27B?
Qwen3.5 27B is the stronger model overall, scoring 41.9 to 33.5 on the Noometry Index. Mercury 2.5 costs 12× less per token, which makes it the better buy when Qwen3.5 27B's lead doesn't matter for your workload.
Which is cheaper, Mercury 2.5 or Qwen3.5 27B?
Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; Qwen3.5 27B lists at $0.30 and $2.40.
Is Mercury 2.5 or Qwen3.5 27B better for coding?
They score almost the same on coding (39.5 vs 38.9); test both on your own repository before choosing.
Which has the bigger context window?
Qwen3.5 27B does, with 262K tokens against 260K.
How many benchmarks do Mercury 2.5 and Qwen3.5 27B share?
1 benchmark has published results for both models. Mercury 2.5 has 4 scored results on Noometry and Qwen3.5 27B has 28.