Hermes 4 405B vs o3 Pro
o3 Pro leads Hermes 4 405B on the Artificial Analysis Intelligence Index, 21.9 to 7.5, and Hermes 4 405B costs 26.7x less per output token ($3.00 vs $80.00 per million). Updated October 21, 2026; 2 benchmarks have a result for both.
Hermes 4 405B or o3 Pro: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Hermes 4 405B for output tokens 26.7x cheaper ($3.00 vs $80.00 per million) and work measured by AA Intelligence Index or Kagi LLM Benchmark, where it leads.
- Shared results
- 2
- Hermes 4 405B only
- 0
- o3 Pro only
- 10
- Like-for-like categories
- 2 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
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
o3 Pro
o3 Pro leads, 21.9 against 7.5.
Same board, both measured
Long documents
Listed context window
o3 Pro
o3 Pro takes 200K tokens against 131K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Hermes 4 405B
Hermes 4 405B $0.0025, o3 Pro $0.060 per turn.
List prices
At a glance
- Coding index
- Hermes 4 405B not benchmarked, o3 Pro not benchmarked.
- Widest category
- Reasoning, 16.3 points apart on average over 1 shared benchmark.
- Widest single gap
- Kagi LLM Benchmark: Hermes 4 405B 55.8% against o3 Pro 72.1%, 16.3 points apart on a 0 to 100 scale.
- Output price
- Hermes 4 405B $3.00 against o3 Pro $80.00 per million output tokens, 26.7x apart.
- Context window
- Hermes 4 405B takes 131K tokens, o3 Pro 200K.
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 | Hermes 4 405B | Bars | o3 Pro | Ties |
|---|---|---|---|---|
| Intelligence | 0 | 1 | ||
| Reasoning | 0 | 1 | ||
| All shared boards | 0 | 2 |
CodingDirectional onlySix of these boards feed the Vibe Coding Index2 boards, none shared
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 84.9% | Only o3 Pro measured |
| WeirdML | Not measured | 58.2% | Only o3 Pro measured |
| Neither model has a result on the other 37 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| AA Intelligence Index | 7.5 | 21.9 | o3 Pro |
| Epoch Capabilities Index | Not measured | 147.3 | Only o3 Pro measured |
Agentic workNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 41 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | Not measured | 84.5% | Only o3 Pro measured |
| ARC-AGI | Not measured | 59.3% | Only o3 Pro measured |
| ARC-AGI-2 | Not measured | 4.9% | Only o3 Pro measured |
| Kagi LLM Benchmark | 55.8% | 72.1% | o3 Pro |
| Neither model has a result on the other 18 boards here | |||
MathNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 13 boards here | |||
KnowledgeNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 18 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | Hermes 4 405B | o3 Pro | Leader |
|---|---|---|---|
| DTBench | Not measured | 86.9% | Only o3 Pro measured |
| LMCA | Not measured | 38.5% | Only o3 Pro measured |
| Fiction.LiveBench | Not measured | 97.2% | Only o3 Pro measured |
| Creative writing (Lech Mazur) | Not measured | 84.4% | Only o3 Pro measured |
| Neither model has a result on the other 42 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Hermes 4 405B | o3 Pro | 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
Hermes 4 405B costs less
Repository review
50K input + 3K output tokens
Hermes 4 405B costs less
Agent loop
200K input + 10K output tokens
Hermes 4 405B 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 | Nous Hermes 4 405B | OpenAI o3 Pro |
|---|---|---|
| Maker | Nous Research | OpenAI |
| Weights | Open weights | No public weights listed |
| Released | August 26, 2025 | June 10, 2025 |
| Context window | 131K | 200K |
| Input $/Mtok | $1.00 | $20.00 |
| Output $/Mtok | $3.00 | $80.00 |
| 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 Hermes 4 405B better than o3 Pro for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Hermes 4 405B for output tokens 26.7x cheaper ($3.00 vs $80.00 per million) and work measured by AA Intelligence Index or Kagi LLM Benchmark, where it leads.
Which is cheaper, Hermes 4 405B or o3 Pro?
Hermes 4 405B costs $1.00 per million input tokens and $3.00 per million output tokens; o3 Pro costs $20.00 and $80.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Hermes 4 405B or o3 Pro?
o3 Pro, with 200K tokens against 131K.
How many benchmarks is the Hermes 4 405B vs o3 Pro comparison based on?
2 benchmarks have a result for both models as of October 21, 2026. Hermes 4 405B's coding index rests on 0 independent benchmarks and o3 Pro's on 0. Where only one model has a result, the page says so instead of naming a winner.