Mercury 2.5 vs Muse Spark 1.3
Muse Spark 1.3 leads Mercury 2.5 on coding, 57.4 to 1.6 on the Vibe Coding Index, and Mercury 2.5 costs 28.3x less per output token ($0.15 vs $4.25 per million). Updated October 22, 2026; 17 benchmarks have a result for both.
Mercury 2.5 or Muse Spark 1.3: which to pick
Pick Muse Spark 1.3 for coding: it scores 57.4 on the Vibe Coding Index against 1.6 for Mercury 2.5.
Pick Mercury 2.5 for output tokens 28.3x cheaper ($0.15 vs $4.25 per million).
- Shared results
- 17
- Mercury 2.5 only
- 5
- Muse Spark 1.3 only
- 75
- Like-for-like categories
- 6 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
Muse Spark 1.3
Muse Spark 1.3 scores 57.4 against 1.6.
2 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Muse Spark 1.3
Muse Spark 1.3 leads, 48.1 against 12.3.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Muse Spark 1.3 has a AA Agentic Index result, 55.5.
Directional only
Web design
Design Arena: websites
No call
Only Muse Spark 1.3 has a Design Arena: websites result, 1356.
Directional only
Long documents
Listed context window
Muse Spark 1.3
Muse Spark 1.3 takes 1.05M tokens against 260K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 2.5
Mercury 2.5 $0.0001, Muse Spark 1.3 $0.0034 per turn.
List prices
At a glance
- Coding index
- Mercury 2.5 1.6 from 2 benchmarks, Muse Spark 1.3 57.4 from 4 benchmarks.
- Widest category
- Math, 55.0 points apart on average over 1 shared benchmark.
- Widest single gap
- Vibe Code Bench (Vals AI): Mercury 2.5 3.7% against Muse Spark 1.3 82.9%, 79.2 points apart on a 0 to 100 scale.
- Output price
- Mercury 2.5 $0.15 against Muse Spark 1.3 $4.25 per million output tokens, 28.3x apart.
- Context window
- Mercury 2.5 takes 260K tokens, Muse Spark 1.3 1.05M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Mercury 2.5 | Bars | Muse Spark 1.3 | Ties |
|---|---|---|---|---|
| Coding | 0 | 8 | ||
| Intelligence | 0 | 1 | ||
| Agentic work | 0 | 5 | ||
| Reasoning | 0 | 1 | ||
| Math | 0 | 1 | ||
| General | 0 | 1 | ||
| All shared boards | 0 | 17 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index08
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 90.2% | Only Muse Spark 1.3 measured |
| LMArena WebDev | Not measured | 1659 | Only Muse Spark 1.3 measured |
| AA Coding Index | Not measured | 75.8 | Only Muse Spark 1.3 measured |
| Terminal-Bench 4 (Vals AI) | 0.0% | 10.6% | Muse Spark 1.3 |
| Vibe Code Bench (Vals AI) | 3.7% | 82.9% | Muse Spark 1.3 |
| Code migration (Vals AI) | 4.5% | 27.6% | Muse Spark 1.3 |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only Muse Spark 1.3 measured |
| IOI (Vals AI) | 2.4% | 43.9% | Muse Spark 1.3 |
| Terminal-Bench 2.1 (Vals AI) | 34.5% | 72.3% | Muse Spark 1.3 |
| SkillsBench (Vals AI) | 18.1% | Not measured | Only Mercury 2.5 measured |
| CyberBench (Vals AI) | 45.5% | 69.4% | Muse Spark 1.3 |
| SciCode | 38.5% | 59.7% | Muse Spark 1.3 |
| FrontierSWE | Not measured | 25.8% | Only Muse Spark 1.3 measured |
| ALE-Bench | 301.6 | 1688.3 | Muse Spark 1.3 |
| LMArena Text: coding | Not measured | 1510 | Only Muse Spark 1.3 measured |
| LMArena Text: software and IT | Not measured | 1511 | Only Muse Spark 1.3 measured |
| LMArena WebDev: React | Not measured | 1672 | Only Muse Spark 1.3 measured |
| LMArena WebDev: HTML | Not measured | 1653 | Only Muse Spark 1.3 measured |
| LMArena WebDev: from an image | Not measured | 1640 | Only Muse Spark 1.3 measured |
| Neither model has a result on the other 20 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 12.3 | 48.1 | Muse Spark 1.3 |
| Epoch Capabilities Index | Not measured | 157.2 | Only Muse Spark 1.3 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 55.5 | Only Muse Spark 1.3 measured |
| Design Arena: agents building web apps | Not measured | 1297 | Only Muse Spark 1.3 measured |
| Design Arena: agents building full-stack apps | Not measured | 1295 | Only Muse Spark 1.3 measured |
| Design Arena: agents building mobile apps | Not measured | 1218 | Only Muse Spark 1.3 measured |
| Design Arena: agents building Godot games | Not measured | 1241 | Only Muse Spark 1.3 measured |
| Design Arena: PowerPoint slides | Not measured | 1219 | Only Muse Spark 1.3 measured |
| Design Arena: spreadsheets | Not measured | 1062 | Only Muse Spark 1.3 measured |
| LiveBench research | Not measured | 68.6% | Only Muse Spark 1.3 measured |
| LiveBench browser | Not measured | 80.0% | Only Muse Spark 1.3 measured |
| LiveBench long agentic | Not measured | 40.4% | Only Muse Spark 1.3 measured |
| Finance Agent (Vals AI) | 18.9% | 58.9% | Muse Spark 1.3 |
| Tax Agent Bench (Vals AI) | 2.5% | 36.0% | Muse Spark 1.3 |
| Legal Research Bench (Vals AI) | 4.3% | 40.9% | Muse Spark 1.3 |
| Excel Modeling Benchmark (Vals AI) | 8.8% | 62.7% | Muse Spark 1.3 |
| Terminal-Bench-Science (Vals AI) | 0.0% | 4.3% | Muse Spark 1.3 |
| APEX-Agents | Not measured | 58.6% | Only Muse Spark 1.3 measured |
| Neither model has a result on the other 25 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| LiveBench reasoning | Not measured | 89.7% | Only Muse Spark 1.3 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 94.1% | Only Muse Spark 1.3 measured |
| Humanity's Last Exam (Artificial Analysis run) | 11.8% | 48.7% | Muse Spark 1.3 |
| Chess puzzles | Not measured | 37.0% | Only Muse Spark 1.3 measured |
| Mystery game puzzles | Not measured | 25.0% | Only Muse Spark 1.3 measured |
| LMArena Text: hard prompts | Not measured | 1503 | Only Muse Spark 1.3 measured |
| LMArena Text: expert | Not measured | 1519 | Only Muse Spark 1.3 measured |
| LMArena Text: hard prompts in English | Not measured | 1500 | Only Muse Spark 1.3 measured |
| LMArena Vision: diagrams | Not measured | 1330 | Only Muse Spark 1.3 measured |
| LMArena Vision: homework | Not measured | 1296 | Only Muse Spark 1.3 measured |
| Neither model has a result on the other 12 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| OTIS Mock AIME | Not measured | 99.2% | Only Muse Spark 1.3 measured |
| FrontierMath, tiers 1 to 3 | Not measured | 74.4% | Only Muse Spark 1.3 measured |
| FrontierMath, tier 4 | Not measured | 46.3% | Only Muse Spark 1.3 measured |
| ProofBench | 3.0% | 58.0% | Muse Spark 1.3 |
| LMArena Text: math | Not measured | 1497 | Only Muse Spark 1.3 measured |
| LMArena Text: mathematical work | Not measured | 1491 | Only Muse Spark 1.3 measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| LegalBench (Vals AI) | 83.1% | Not measured | Only Mercury 2.5 measured |
| MedCode (Vals AI) | 31.3% | Not measured | Only Mercury 2.5 measured |
| LMArena Text: science | Not measured | 1507 | Only Muse Spark 1.3 measured |
| LMArena Text: medicine and healthcare | Not measured | 1493 | Only Muse Spark 1.3 measured |
| LMArena Text: legal and government | Not measured | 1499 | Only Muse Spark 1.3 measured |
| LMArena Text: business and finance | Not measured | 1490 | Only Muse Spark 1.3 measured |
| Neither model has a result on the other 12 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 1356 | Only Muse Spark 1.3 measured |
| Design Arena: UI components | Not measured | 1349 | Only Muse Spark 1.3 measured |
| Design Arena: game dev | Not measured | 1328 | Only Muse Spark 1.3 measured |
| Design Arena: data viz | Not measured | 1343 | Only Muse Spark 1.3 measured |
| Design Arena: 3D | Not measured | 1358 | Only Muse Spark 1.3 measured |
| Design Arena: all code categories | Not measured | 1352 | Only Muse Spark 1.3 measured |
| Design Arena: SVG | Not measured | 1301 | Only Muse Spark 1.3 measured |
| Design Arena: ASCII art | Not measured | 1278 | Only Muse Spark 1.3 measured |
| LiveBench design | Not measured | 74.8% | Only Muse Spark 1.3 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| LiveBench data analysis | Not measured | 79.6% | Only Muse Spark 1.3 measured |
| Public Benefits Bench (Vals AI) | 45.3% | Not measured | Only Mercury 2.5 measured |
| MedScribe (Vals AI) | 55.1% | Not measured | Only Mercury 2.5 measured |
| Long context reasoning (AA-LCR) | 71.7% | 83.0% | Muse Spark 1.3 |
| DTBench | Not measured | 96.5% | Only Muse Spark 1.3 measured |
| LMCA | Not measured | 53.9% | Only Muse Spark 1.3 measured |
| LMArena Text | Not measured | 1490 | Only Muse Spark 1.3 measured |
| LMArena Text: instruction following | Not measured | 1479 | Only Muse Spark 1.3 measured |
| LMArena Text: creative writing | Not measured | 1462 | Only Muse Spark 1.3 measured |
| LMArena Vision | Not measured | 1308 | Only Muse Spark 1.3 measured |
| LMArena Text: English | Not measured | 1495 | Only Muse Spark 1.3 measured |
| LMArena Text: non-English | Not measured | 1481 | Only Muse Spark 1.3 measured |
| LMArena Text: Chinese | Not measured | 1532 | Only Muse Spark 1.3 measured |
| LMArena Text: German | Not measured | 1513 | Only Muse Spark 1.3 measured |
| LMArena Text: Japanese | Not measured | 1470 | Only Muse Spark 1.3 measured |
| LMArena Text: Korean | Not measured | 1490 | Only Muse Spark 1.3 measured |
| LMArena Text: French | Not measured | 1511 | Only Muse Spark 1.3 measured |
| LMArena Text: Spanish | Not measured | 1496 | Only Muse Spark 1.3 measured |
| LMArena Text: Russian | Not measured | 1491 | Only Muse Spark 1.3 measured |
| LMArena Text: Polish | Not measured | 1490 | Only Muse Spark 1.3 measured |
| LMArena Text: multi-turn | Not measured | 1487 | Only Muse Spark 1.3 measured |
| LMArena Text: longer queries | Not measured | 1488 | Only Muse Spark 1.3 measured |
| LMArena Text: writing and language | Not measured | 1470 | Only Muse Spark 1.3 measured |
| LMArena Text: entertainment and media | Not measured | 1457 | Only Muse Spark 1.3 measured |
| LMArena Vision: English | Not measured | 1298 | Only Muse Spark 1.3 measured |
| LMArena Vision: Chinese | Not measured | 1384 | Only Muse Spark 1.3 measured |
| LMArena Vision: reading text | Not measured | 1319 | Only Muse Spark 1.3 measured |
| LMArena Vision: humor | Not measured | 1293 | Only Muse Spark 1.3 measured |
| LMArena Vision: creative writing | Not measured | 1296 | Only Muse Spark 1.3 measured |
| Neither model has a result on the other 17 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mercury 2.5 | Muse Spark 1.3 | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Mercury 2.5 costs less
Repository review
50K input + 3K output tokens
Mercury 2.5 costs less
Agent loop
200K input + 10K output tokens
Mercury 2.5 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Inception Mercury 2.5 | Meta Muse Spark 1.3 |
|---|---|---|
| Maker | Inception | Meta |
| Weights | No public weights listed | No public weights listed |
| Released | September 8, 2026 | September 2, 2026 |
| Context window | 260K | 1.05M |
| Input $/Mtok | $0.04 | $1.25 |
| Output $/Mtok | $0.15 | $4.25 |
| Coding index | 1.6 | 57.4 |
| Independent measurements behind it | 2 | 4 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Mercury 2.5 better than Muse Spark 1.3 for coding?
Pick Muse Spark 1.3 for coding: it scores 57.4 on the Vibe Coding Index against 1.6 for Mercury 2.5. Pick Mercury 2.5 for output tokens 28.3x cheaper ($0.15 vs $4.25 per million).
Which is cheaper, Mercury 2.5 or Muse Spark 1.3?
Mercury 2.5 costs $0.04 per million input tokens and $0.15 per million output tokens; Muse Spark 1.3 costs $1.25 and $4.25. Cost per solved task is known for neither of them.
Which has the bigger context window, Mercury 2.5 or Muse Spark 1.3?
Muse Spark 1.3, with 1.05M tokens against 260K.
How many benchmarks is the Mercury 2.5 vs Muse Spark 1.3 comparison based on?
17 benchmarks have a result for both models as of October 22, 2026. Mercury 2.5's coding index rests on 2 independent benchmarks and Muse Spark 1.3's on 4. Where only one model has a result, the page says so instead of naming a winner.