Mercury 3 vs Hermes 4 405B
Mercury 3 costs 8.6x less per output token than Hermes 4 405B ($0.35 vs $3.00 per million). Updated October 22, 2026; no benchmark has tested both models yet.
- Coding
- No data
- Overall
- No data
- Output $/M
- $0.35
- Coding
- No data
- Overall
- No data
- Output $/M
- $3.00
Mercury 3 or Hermes 4 405B: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Mercury 3 for output tokens 8.6x cheaper ($0.35 vs $3.00 per million) and a larger context window (1M against 131K tokens).
No benchmark has tested both yet. Mercury 3 has results on Design Arena: websites, Design Arena: UI components and Design Arena: game dev; Hermes 4 405B on AA Intelligence Index and Kagi LLM Benchmark. 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 Hermes 4 405B has a AA Intelligence Index result, 7.5.
Directional only
Web design
Design Arena: websites
No call
Only Mercury 3 has a Design Arena: websites result, 1242.
Directional only
Long documents
Listed context window
Mercury 3
Mercury 3 takes 1M tokens against 131K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 3
Mercury 3 $0.0003, Hermes 4 405B $0.0025 per turn.
List prices
At a glance
- Coding index
- Mercury 3 not benchmarked, Hermes 4 405B 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 Hermes 4 405B $3.00 per million output tokens, 8.6x apart.
- Context window
- Mercury 3 takes 1M tokens, Hermes 4 405B 131K.
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 | Hermes 4 405B | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 7.5 | Only Hermes 4 405B measured |
| Neither model has a result on the other 1 board here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | Mercury 3 | Hermes 4 405B | Leader |
|---|---|---|---|
| Kagi LLM Benchmark | Not measured | 55.8% | Only Hermes 4 405B measured |
| Neither model has a result on the other 21 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index5 boards measured
| Benchmark | Mercury 3 | Hermes 4 405B | Leader |
|---|---|---|---|
| Design Arena: websites | 1242 | Not measured | Only Mercury 3 measured |
| Design Arena: UI components | 1255 | Not measured | Only Mercury 3 measured |
| Design Arena: game dev | 1225 | Not measured | Only Mercury 3 measured |
| Design Arena: data viz | 1192 | Not measured | Only Mercury 3 measured |
| Design Arena: all code categories | 1237 | Not measured | Only Mercury 3 measured |
| Neither model has a result on the other 4 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 | Nous Hermes 4 405B |
|---|---|---|
| Maker | Inception | Nous Research |
| Weights | No public weights listed | Open weights |
| Released | October 16, 2026 | August 26, 2025 |
| Context window | 1M | 131K |
| Input $/Mtok | $0.10 | $1.00 |
| Output $/Mtok | $0.35 | $3.00 |
| 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 Hermes 4 405B for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Mercury 3 for output tokens 8.6x cheaper ($0.35 vs $3.00 per million) and a larger context window (1M against 131K tokens).
Which is cheaper, Mercury 3 or Hermes 4 405B?
Mercury 3 costs $0.10 per million input tokens and $0.35 per million output tokens; Hermes 4 405B costs $1.00 and $3.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Mercury 3 or Hermes 4 405B?
Mercury 3, with 1M tokens against 131K.
Has any benchmark tested both Mercury 3 and Hermes 4 405B?
No benchmark has tested both yet. Mercury 3 has results on Design Arena: websites, Design Arena: UI components and Design Arena: game dev; Hermes 4 405B on AA Intelligence Index and Kagi LLM Benchmark. Compare them on price and context instead. Data as of October 22, 2026.