Model comparison
Grok 4.20 (Non-Reasoning) vs Mercury 2.5
Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.6 to 33.5 on the Noometry Index. Mercury 2.5 costs 23× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. Grok 4.20 (Non-Reasoning) scores higher in 3 categories and Mercury 2.5 in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.20 (Non-Reasoning) leads 52.3 to 22.4.
- The biggest single-benchmark swing is ProofBench: 14% for Grok 4.20 (Non-Reasoning) and 3% for Mercury 2.5.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $1.25 / $2.50 for Grok 4.20 (Non-Reasoning).
- Grok 4.20 (Non-Reasoning) accepts more context: 1M tokens versus 260K.
Side by side
| Grok 4.20 (Non-Reasoning) | Mercury 2.5 | |
|---|---|---|
| Provider | xAI | Inception |
| Noometry Index | 48.6 | 33.5 |
| Released | 2026-02-17 | 2026-09-08 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 260K |
| Max output | 30K | 66K |
| Input $ / M tokens | $1.25 | $0.04 |
| Output $ / M tokens | $2.50 | $0.15 |
| Results tracked | 46 | 4 |
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Category by category
Coding Grok 4.20 (Non-Reasoning) leads
Grok 4.20 (Non-Reasoning): 42.1 (#112), Mercury 2.5: 39.5 (#156)
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| ALE-Bench | 1,150 | 301.65 |
| LMArena WebDev | 1375 | — |
| SciCode | — | 38.5% |
| WeirdML | 52.3% | — |
| LMArena Coding | 1459 | — |
Agentic & Tool Use Not comparable
Grok 4.20 (Non-Reasoning): 34.4 (#46), Mercury 2.5: —
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| Terminal-Bench | 57.3% | — |
| τ²-bench Banking | 18% | — |
| LMArena Search | 1189 | — |
| Vending-Bench 2 | 4,663 | — |
Reasoning Grok 4.20 (Non-Reasoning) leads
Grok 4.20 (Non-Reasoning): 52.3 (#32), Mercury 2.5: 22.4 (#193)
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| ARC-AGI-2 | 65.1% | — |
| Kagi LLM Benchmark | 75% | — |
| NYT Connections (extended) | 85.4% | — |
| ARC-AGI-1 | 89.5% | — |
| CritPt | — | 0% |
| Chess Puzzles | 24% | — |
| Thematic Generalization | 63.8% | — |
| LMArena Hard Prompts | 1451 | — |
| DTBench | 90.1% | — |
| LMCA | 38.7% | — |
| Epoch Capabilities Index | 151.98 | — |
| ForecastBench | 61.4 | — |
Math Grok 4.20 (Non-Reasoning) leads
Grok 4.20 (Non-Reasoning): 48.2 (#65), Mercury 2.5: 23.3 (#272)
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| ProofBench | 14% | 3% |
| FrontierMath (Tiers 1-3) | 44.9% | — |
| FrontierMath Tier 4 | 17.1% | — |
| OTIS Mock AIME 2024-2025 | 92.2% | — |
| LMArena Math | 1455 | — |
Knowledge Not comparable
Grok 4.20 (Non-Reasoning): 52.8 (#60), Mercury 2.5: —
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| GPQA Diamond | 89.3% | — |
| SimpleQA Verified | 30.2% | — |
| LMArena Expert | 1439 | — |
Multimodal Not comparable
Grok 4.20 (Non-Reasoning): 33.3 (#98), Mercury 2.5: —
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| LMArena Vision | 1263 | — |
| Blueprint-Bench 2 | 0% | — |
| LMArena Document | 1416 | — |
Multilingual Not comparable
Grok 4.20 (Non-Reasoning): 54.5 (#40), Mercury 2.5: —
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| LMArena Non-English | 1441 | — |
| LMArena Chinese | 1481 | — |
| LMArena French | 1476 | — |
| LMArena German | 1465 | — |
| LMArena Japanese | 1449 | — |
| LMArena Korean | 1417 | — |
| LMArena Russian | 1458 | — |
| LMArena Spanish | 1443 | — |
Instruction Following Not comparable
Grok 4.20 (Non-Reasoning): 74.8 (#83), Mercury 2.5: —
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| LMArena Instruction Following | 1420 | — |
Long Context Not comparable
Grok 4.20 (Non-Reasoning): 45.5 (#34), Mercury 2.5: —
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| CL-bench | 22.2% | — |
| CL-bench Life | 11.9% | — |
| LMArena Longer Query | 1437 | — |
Writing & Preference Not comparable
Grok 4.20 (Non-Reasoning): 65.7 (#44), Mercury 2.5: —
| Benchmark | Grok 4.20 (Non-Reasoning) | Mercury 2.5 |
|---|---|---|
| LMArena Text | 1451 | — |
| LMArena Creative Writing | 1438 | — |
| EQ-Bench Creative Writing | 1574 | — |
| LMArena Multi-Turn | 1456 | — |
Frequently asked questions
Is Grok 4.20 (Non-Reasoning) better than Mercury 2.5?
Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.6 to 33.5 on the Noometry Index. Mercury 2.5 costs 23× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.
Which is cheaper, Grok 4.20 (Non-Reasoning) or Mercury 2.5?
Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; Grok 4.20 (Non-Reasoning) lists at $1.25 and $2.50.
Is Grok 4.20 (Non-Reasoning) or Mercury 2.5 better for coding?
Grok 4.20 (Non-Reasoning) scores higher on coding benchmarks: 42.1 versus 39.5 in the Noometry coding category.
Which has the bigger context window?
Grok 4.20 (Non-Reasoning) does, with 1M tokens against 260K.
How many benchmarks do Grok 4.20 (Non-Reasoning) and Mercury 2.5 share?
2 benchmarks have published results for both models. Grok 4.20 (Non-Reasoning) has 46 scored results on Noometry and Mercury 2.5 has 4.