Mercury 3 vs Fugu Ultra
Mercury 3 costs 85.7x less per output token than Fugu Ultra ($0.35 vs $30.00 per million). Updated October 23, 2026; no benchmark has tested both models yet.
- Coding
- 29.3
- Overall
- No data
- Output $/M
- $0.35
- Coding
- No data
- Overall
- No data
- Output $/M
- $30.00
Mercury 3 or Fugu Ultra: which to pick
Only Mercury 3 has a coding score, 29.3 on the Vibe Coding Index; Fugu Ultra has none, so the two cannot be ranked on coding.
Compare them on price, context and the boards below.
No benchmark has tested both yet. Mercury 3 has results on Terminal-Bench 4 (Vals AI), Vibe Code Bench (Vals AI) and Tax Agent Bench (Vals AI); Fugu Ultra has none yet. 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
Only Mercury 3 has a coding score, so no call is made.
One side not measured
Web design
Design Arena: websites
No call
Only Mercury 3 has a Design Arena: websites result, 1226.
Directional only
General
Vals Index
No call
Only Mercury 3 has a Vals Index result, 43.7%.
Directional only
Long documents
Listed context window
No call
Both take 1M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 3
Mercury 3 $0.0003, Fugu Ultra $0.020 per turn.
List prices
At a glance
- Coding index
- Mercury 3 29.3 from 2 benchmarks, Fugu Ultra 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 Fugu Ultra $30.00 per million output tokens, 85.7x apart.
- Context window
- Both take 1M tokens.
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 Index2 boards measured
| Benchmark | Mercury 3 | Fugu Ultra | Leader |
|---|---|---|---|
| Terminal-Bench 4 (Vals AI) | 3.0% | Not measured | Only Mercury 3 measured |
| Vibe Code Bench (Vals AI) | 60.9% | Not measured | Only Mercury 3 measured |
| Neither model has a result on the other 41 boards here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index3 boards measured
| Benchmark | Mercury 3 | Fugu Ultra | Leader |
|---|---|---|---|
| Tax Agent Bench (Vals AI) | 18.2% | Not measured | Only Mercury 3 measured |
| Legal Research Bench (Vals AI) | 28.9% | Not measured | Only Mercury 3 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 5.0% | Not measured | Only Mercury 3 measured |
| Neither model has a result on the other 39 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index6 boards measured
| Benchmark | Mercury 3 | Fugu Ultra | Leader |
|---|---|---|---|
| Design Arena: websites | 1226 | Not measured | Only Mercury 3 measured |
| Design Arena: UI components | 1247 | Not measured | Only Mercury 3 measured |
| Design Arena: game dev | 1227 | Not measured | Only Mercury 3 measured |
| Design Arena: data viz | 1201 | Not measured | Only Mercury 3 measured |
| Design Arena: all code categories | 1231 | Not measured | Only Mercury 3 measured |
| Design Arena: SVG | 1174 | Not measured | Only Mercury 3 measured |
| Neither model has a result on the other 3 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | Mercury 3 | Fugu Ultra | Leader |
|---|---|---|---|
| Vals Index | 43.7% | Not measured | Only Mercury 3 measured |
| Neither model has a result on the other 47 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 | Sakana Fugu Ultra |
|---|---|---|
| Maker | Inception | Sakana |
| Weights | No public weights listed | No public weights listed |
| Released | October 16, 2026 | June 24, 2026 |
| Context window | 1M | 1M |
| Input $/Mtok | $0.10 | $5.00 |
| Output $/Mtok | $0.35 | $30.00 |
| Coding index | 29.3 | Not benchmarked |
| Independent measurements behind it | 2 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Mercury 3 better than Fugu Ultra for coding?
Only Mercury 3 has a coding score, 29.3 on the Vibe Coding Index; Fugu Ultra has none, so the two cannot be ranked on coding. Compare them on price, context and the boards below.
Which is cheaper, Mercury 3 or Fugu Ultra?
Mercury 3 costs $0.10 per million input tokens and $0.35 per million output tokens; Fugu Ultra costs $5.00 and $30.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Mercury 3 or Fugu Ultra?
Neither: both take 1M tokens.
Has any benchmark tested both Mercury 3 and Fugu Ultra?
No benchmark has tested both yet. Mercury 3 has results on Terminal-Bench 4 (Vals AI), Vibe Code Bench (Vals AI) and Tax Agent Bench (Vals AI); Fugu Ultra has none yet. Compare them on price and context instead. Data as of October 23, 2026.