Model comparison
Mercury 2 vs Qwen3.5 Plus
Qwen3.5 Plus is the stronger model overall, scoring 42.3 to 38.8 on the Noometry Index. Mercury 2 costs 2.4× less per token, which makes it the better buy when Qwen3.5 Plus's lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
Alibaba (Qwen)Summary
- They share 2 benchmarks with published results for both. Mercury 2 scores higher in 0 categories and Qwen3.5 Plus in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Qwen3.5 Plus leads 46.0 to 35.6.
- Mercury 2 is cheaper at $0.25 / $0.75 per million input/output tokens, against $0.40 / $2.40 for Qwen3.5 Plus.
- Qwen3.5 Plus accepts more context: 1M tokens versus 128K.
Side by side
| Mercury 2 | Qwen3.5 Plus | |
|---|---|---|
| Provider | Inception | Alibaba (Qwen) |
| Noometry Index | 38.8 | 42.3 |
| Released | 2026-02-20 | 2026-02-16 |
| Weights | Proprietary | Proprietary |
| Context window | 128K | 1M |
| Max output | 50K | 66K |
| Input $ / M tokens | $0.25 | $0.40 |
| Output $ / M tokens | $0.75 | $2.40 |
| Results tracked | 17 | 15 |
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Category by category
Coding Not comparable
Mercury 2: 33.2 (#250), Qwen3.5 Plus: —
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| ALE-Bench | 785.58 | 621.92 |
| LMArena WebDev | 1170 | — |
| SciCode | 38.7% | — |
| WeirdML | 43.2% | — |
| LMArena Coding | 1391 | — |
Agentic & Tool Use Not comparable
Mercury 2: —, Qwen3.5 Plus: —
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| Vending-Bench 2 | — | 0.54 |
Reasoning Qwen3.5 Plus leads
Mercury 2: 23.0 (#170), Qwen3.5 Plus: 32.0 (#67)
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| CritPt | 0.8% | — |
| Chess Puzzles | — | 22% |
| LMArena Hard Prompts | 1362 | — |
| Mystery Game Puzzles | — | 17% |
| DTBench | — | 80.5% |
| LMCA | — | 36.4% |
| Epoch Capabilities Index | — | 146.79 |
Math Not comparable
Mercury 2: —, Qwen3.5 Plus: 47.9 (#55)
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| OTIS Mock AIME 2024-2025 | — | 86.7% |
| FrontierMath (Feb 2025 set) | — | 21% |
| FrontierMath Tier 4 (v1) | — | 2.1% |
Knowledge Qwen3.5 Plus leads
Mercury 2: 35.6 (#170), Qwen3.5 Plus: 46.0 (#78)
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| Vectara Hallucination Rate | 12.3% | 10.7% |
| GPQA Diamond | — | 84.8% |
| SimpleQA Verified | — | 25.4% |
| LMArena Expert | 1358 | — |
Multilingual Not comparable
Mercury 2: 46.8 (#153), Qwen3.5 Plus: —
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| LMArena Non-English | 1331 | — |
| LMArena Chinese | 1416 | — |
| LMArena Russian | 1303 | — |
Instruction Following Not comparable
Mercury 2: 70.4 (#161), Qwen3.5 Plus: —
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| LMArena Instruction Following | 1328 | — |
Long Context Qwen3.5 Plus leads
Mercury 2: 40.4 (#149), Qwen3.5 Plus: 42.9 (#109)
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| CL-bench | — | 19.8% |
| CL-bench Life | — | 12.4% |
| LMArena Longer Query | 1329 | — |
Writing & Preference Not comparable
Mercury 2: 54.0 (#151), Qwen3.5 Plus: —
| Benchmark | Mercury 2 | Qwen3.5 Plus |
|---|---|---|
| LMArena Text | 1355 | — |
| LMArena Creative Writing | 1289 | — |
| LMArena Multi-Turn | 1358 | — |
Frequently asked questions
Is Mercury 2 better than Qwen3.5 Plus?
Qwen3.5 Plus is the stronger model overall, scoring 42.3 to 38.8 on the Noometry Index. Mercury 2 costs 2.4× less per token, which makes it the better buy when Qwen3.5 Plus's lead doesn't matter for your workload.
Which is cheaper, Mercury 2 or Qwen3.5 Plus?
Mercury 2 is cheaper. It lists at $0.25 per million input tokens and $0.75 per million output tokens; Qwen3.5 Plus lists at $0.40 and $2.40.
Which has the bigger context window?
Qwen3.5 Plus does, with 1M tokens against 128K.
How many benchmarks do Mercury 2 and Qwen3.5 Plus share?
2 benchmarks have published results for both models. Mercury 2 has 17 scored results on Noometry and Qwen3.5 Plus has 15.