Mercury 3 vs Sonar Reasoning Pro
Updated October 21, 2026. No benchmark has tested both models yet. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
- Coding
- No data
- Overall
- No data
- Output $/M
- $0.35
- Coding
- No data
- Overall
- 11.8
- Output $/M
- $8.00
Decision reading
Neither model has a coding score yet, so the two cannot be ranked on coding.
Mercury 3 has the edge where output tokens cost 22.9x less, and where the context window is larger, 1M against 128K tokens.
No benchmark has tested both yet. Mercury 3 has results on Design Arena: websites, Design Arena: UI components and Design Arena: game dev; Sonar Reasoning Pro on AA Intelligence Index. Compare them on price and context instead.
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
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Sonar Reasoning Pro has a AA Intelligence Index result, 11.8.
Directional only
Web design
Design Arena: websites
No call
Only Mercury 3 has a Design Arena: websites result, 1241.
Directional only
Long documents
Listed context window
Mercury 3
Mercury 3 takes 1M tokens against 128K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 3
Mercury 3 $0.0003, Sonar Reasoning Pro $0.0060 per turn.
List prices
At a glance
- Coding index
- Mercury 3 not benchmarked, Sonar Reasoning Pro not benchmarked.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- Mercury 3 $0.35 against Sonar Reasoning Pro $8.00 per million output tokens, 22.9x apart.
- Context window
- Mercury 3 takes 1M tokens, Sonar Reasoning Pro 128K.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | Mercury 3 | Sonar Reasoning Pro | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 11.8 | Only Sonar Reasoning Pro measured |
| Neither model has a result on the other 1 board here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index4 boards measured
| Benchmark | Mercury 3 | Sonar Reasoning Pro | Leader |
|---|---|---|---|
| Design Arena: websites | 1241 | Not measured | Only Mercury 3 measured |
| Design Arena: UI components | 1268 | Not measured | Only Mercury 3 measured |
| Design Arena: game dev | 1215 | Not measured | Only Mercury 3 measured |
| Design Arena: all code categories | 1236 | Not measured | Only Mercury 3 measured |
| Neither model has a result on the other 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 3 costs less
Repository review
50K input + 3K output tokens
Mercury 3 costs less
Agent loop
200K input + 10K output tokens
Mercury 3 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 3 | Perplexity Sonar Reasoning Pro |
|---|---|---|
| Maker | Inception | Perplexity |
| Weights | No public weights listed | No public weights listed |
| Released | October 16, 2026 | March 7, 2025 |
| Context window | 1M | 128K |
| Input $/Mtok | $0.10 | $2.00 |
| Output $/Mtok | $0.35 | $8.00 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Mercury 3 better than Sonar Reasoning Pro for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Mercury 3 has the edge where output tokens cost 22.9x less, and where the context window is larger, 1M against 128K tokens.
Which is cheaper, Mercury 3 or Sonar Reasoning Pro?
Mercury 3 costs $0.10 per million input tokens and $0.35 per million output tokens; Sonar Reasoning Pro costs $2.00 and $8.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Mercury 3 or Sonar Reasoning Pro?
Mercury 3, with 1M tokens against 128K.
Has any benchmark tested both Mercury 3 and Sonar Reasoning Pro?
No benchmark has tested both yet. Mercury 3 has results on Design Arena: websites, Design Arena: UI components and Design Arena: game dev; Sonar Reasoning Pro on AA Intelligence Index. Compare them on price and context instead. Data as of October 21, 2026.