GPT-5.6 Sol Pro vs Mercury 3
Mercury 3 costs 57.1x less per output token than GPT-5.6 Sol Pro ($0.35 vs $20.00 per million). Updated October 22, 2026; no benchmark has tested both models yet.
- Coding
- No data
- Overall
- No data
- Output $/M
- $20.00
- Coding
- No data
- Overall
- No data
- Output $/M
- $0.35
GPT-5.6 Sol Pro or Mercury 3: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick GPT-5.6 Sol Pro for a larger context window (1.05M against 1M tokens).
No benchmark has tested both yet. GPT-5.6 Sol Pro has results on WeirdML, APEX-Agents and SimpleBench; Mercury 3 on Design Arena: websites, Design Arena: UI components and Design Arena: game dev. 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
Web design
Design Arena: websites
No call
Only Mercury 3 has a Design Arena: websites result, 1242.
Directional only
Long documents
Listed context window
GPT-5.6 Sol Pro
GPT-5.6 Sol Pro takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 3
GPT-5.6 Sol Pro $0.014, Mercury 3 $0.0003 per turn.
List prices
At a glance
- Coding index
- GPT-5.6 Sol Pro not benchmarked, Mercury 3 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
- GPT-5.6 Sol Pro $20.00 against Mercury 3 $0.35 per million output tokens, 57.1x apart.
- Context window
- GPT-5.6 Sol Pro takes 1.05M tokens, Mercury 3 1M.
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.
CodingDirectional onlySix of these boards feed the Vibe Coding Index1 board measured
| Benchmark | GPT-5.6 Sol Pro | Mercury 3 | Leader |
|---|---|---|---|
| WeirdML | 89.4% | Not measured | Only GPT-5.6 Sol Pro measured |
| Neither model has a result on the other 38 boards here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | GPT-5.6 Sol Pro | Mercury 3 | Leader |
|---|---|---|---|
| APEX-Agents | 51.4% | Not measured | Only GPT-5.6 Sol Pro measured |
| Neither model has a result on the other 40 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | GPT-5.6 Sol Pro | Mercury 3 | Leader |
|---|---|---|---|
| SimpleBench | 71.7% | Not measured | Only GPT-5.6 Sol Pro measured |
| Chess puzzles | 68.0% | Not measured | Only GPT-5.6 Sol Pro measured |
| Neither model has a result on the other 20 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | GPT-5.6 Sol Pro | Mercury 3 | Leader |
|---|---|---|---|
| FrontierMath, tier 4 | 80.5% | Not measured | Only GPT-5.6 Sol Pro measured |
| Neither model has a result on the other 12 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index5 boards measured
| Benchmark | GPT-5.6 Sol Pro | Mercury 3 | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 1242 | Only Mercury 3 measured |
| Design Arena: UI components | Not measured | 1255 | Only Mercury 3 measured |
| Design Arena: game dev | Not measured | 1225 | Only Mercury 3 measured |
| Design Arena: data viz | Not measured | 1192 | Only Mercury 3 measured |
| Design Arena: all code categories | Not measured | 1237 | Only Mercury 3 measured |
| Neither model has a result on the other 4 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
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 | OpenAI GPT-5.6 Sol Pro | Inception Mercury 3 |
|---|---|---|
| Maker | OpenAI | Inception |
| Weights | No public weights listed | No public weights listed |
| Released | July 9, 2026 | October 16, 2026 |
| Context window | 1.05M | 1M |
| Input $/Mtok | $4.00 | $0.10 |
| Output $/Mtok | $20.00 | $0.35 |
| 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 GPT-5.6 Sol Pro better than Mercury 3 for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick GPT-5.6 Sol Pro for a larger context window (1.05M against 1M tokens).
Which is cheaper, GPT-5.6 Sol Pro or Mercury 3?
GPT-5.6 Sol Pro costs $4.00 per million input tokens and $20.00 per million output tokens; Mercury 3 costs $0.10 and $0.35. Cost per solved task is known for neither of them.
Which has the bigger context window, GPT-5.6 Sol Pro or Mercury 3?
GPT-5.6 Sol Pro, with 1.05M tokens against 1M.
Has any benchmark tested both GPT-5.6 Sol Pro and Mercury 3?
No benchmark has tested both yet. GPT-5.6 Sol Pro has results on WeirdML, APEX-Agents and SimpleBench; Mercury 3 on Design Arena: websites, Design Arena: UI components and Design Arena: game dev. Compare them on price and context instead. Data as of October 22, 2026.