Claude Sonnet 4.5 vs o3 Pro
Updated October 21, 2026. 7 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick o3 Pro for coding: it scores 84.9 on the Vibe Coding Index against 59.1 for Claude Sonnet 4.5, though on 1 benchmark against 2.
Pick Claude Sonnet 4.5 when output tokens cost 5.3x less, or when the context window is larger, 1M against 200K tokens.
- Shared results
- 7
- Claude Sonnet 4.5 only
- 85
- o3 Pro only
- 4
- Like-for-like categories
- 4 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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, four public coding benchmarks
o3 Pro
o3 Pro scores 84.9 against 59.1.
2 and 1 benchmarks behind the scores
Intelligence
AA Intelligence Index
o3 Pro
o3 Pro leads, 21.9 against 20.7.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Claude Sonnet 4.5 has a AA Agentic Index result, 15.8.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Sonnet 4.5 has a GPQA Diamond result, 81.6%.
Directional only
Math
AIME
No call
Only Claude Sonnet 4.5 has a AIME result, 88.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Sonnet 4.5 has a MMLU Pro result, 87.4%.
Directional only
Web design
Design Arena: websites
No call
Only Claude Sonnet 4.5 has a Design Arena: websites result, 1190.
Directional only
Long documents
Listed context window
Claude Sonnet 4.5
Claude Sonnet 4.5 takes 1M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Claude Sonnet 4.5
Claude Sonnet 4.5 $0.011, o3 Pro $0.060 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Sonnet 4.5 has the number, $1.16.
Directional only
At a glance
- Coding index
- Claude Sonnet 4.5 59.1 from 2 benchmarks, o3 Pro 84.9 from 1 benchmark.
- Widest category
- Coding, 10.5 points apart on average over 1 shared benchmark.
- Widest single gap
- WeirdML: Claude Sonnet 4.5 47.7% against o3 Pro 58.2%, 10.5 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 4.5 $15.00 against o3 Pro $80.00 per million output tokens, 5.3x apart.
- Context window
- Claude Sonnet 4.5 takes 1M 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 | Claude Sonnet 4.5 | Bars | o3 Pro | Ties |
|---|---|---|---|---|
| Coding | 0 | 1 | ||
| Intelligence | 0 | 2 | ||
| Reasoning | 2 | 0 | ||
| General | 1 | 1 | ||
| All shared boards | 3 | 4 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index01
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 84.9% | Only o3 Pro measured |
| SWE-bench Verified | 74.8% | Not measured | Only Claude Sonnet 4.5 measured |
| SWE-bench Multilingual | 67.0% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena WebDev | 1394 | Not measured | Only Claude Sonnet 4.5 measured |
| AA Coding Index | 52.1 | Not measured | Only Claude Sonnet 4.5 measured |
| LiveCodeBench (Vals AI) | 73.0% | Not measured | Only Claude Sonnet 4.5 measured |
| SWE-bench Verified (Vals AI) | 70.0% | Not measured | Only Claude Sonnet 4.5 measured |
| Vibe Code Bench (Vals AI) | 22.6% | Not measured | Only Claude Sonnet 4.5 measured |
| Terminal-Bench | 46.5% | Not measured | Only Claude Sonnet 4.5 measured |
| GSO-Bench | 14.7% | Not measured | Only Claude Sonnet 4.5 measured |
| WeirdML | 47.7% | 58.2% | o3 Pro |
| Cybench | 60.0% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: coding | 1488 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: software and IT | 1473 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena WebDev: React | 1386 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena WebDev: HTML | 1399 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 22 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| AA Intelligence Index | 20.7 | 21.9 | o3 Pro |
| Epoch Capabilities Index | 146.7 | 147.3 | o3 Pro |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index10 boards, none shared
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| AA Agentic Index | 15.8 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building web apps | 1060 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building full-stack apps | 1050 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building mobile apps | 1137 | Not measured | Only Claude Sonnet 4.5 measured |
| METR time horizons | 67.4% | Not measured | Only Claude Sonnet 4.5 measured |
| Remote Labor Index | 2.1% | Not measured | Only Claude Sonnet 4.5 measured |
| GDPval | 42.5% | Not measured | Only Claude Sonnet 4.5 measured |
| DeepResearch Bench | 52.6% | Not measured | Only Claude Sonnet 4.5 measured |
| OSWorld | 62.9% | Not measured | Only Claude Sonnet 4.5 measured |
| Vending-Bench 2 | $3,839 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 29 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| GPQA Diamond | 81.6% | Not measured | Only Claude Sonnet 4.5 measured |
| MMMU Pro (Vals AI) | 79.3% | Not measured | Only Claude Sonnet 4.5 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 84.5% | Only o3 Pro measured |
| GPQA Diamond (Epoch AI run) | 82.3% | Not measured | Only Claude Sonnet 4.5 measured |
| ARC-AGI | 63.7% | 59.3% | Claude Sonnet 4.5 |
| ARC-AGI-2 | 13.6% | 4.9% | Claude Sonnet 4.5 |
| SimpleBench | 54.3% | Not measured | Only Claude Sonnet 4.5 measured |
| Chess puzzles | 10.0% | Not measured | Only Claude Sonnet 4.5 measured |
| Mystery game puzzles | 17.0% | Not measured | Only Claude Sonnet 4.5 measured |
| EBR-bench | 2.4% | Not measured | Only Claude Sonnet 4.5 measured |
| VPCT | 39.8% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts | 1462 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: expert | 1483 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts in English | 1471 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 7 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| AIME | 88.2% | Not measured | Only Claude Sonnet 4.5 measured |
| MGSM (Vals AI) | 94.3% | Not measured | Only Claude Sonnet 4.5 measured |
| OTIS Mock AIME | 77.8% | Not measured | Only Claude Sonnet 4.5 measured |
| FrontierMath, tiers 1 to 3 | 23.9% | Not measured | Only Claude Sonnet 4.5 measured |
| FrontierMath, tier 4 | 2.4% | Not measured | Only Claude Sonnet 4.5 measured |
| ProofBench | 19.0% | Not measured | Only Claude Sonnet 4.5 measured |
| MATH level 5 | 97.7% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: math | 1449 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: mathematical work | 1462 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 4 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index13 boards, none shared
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| MMLU Pro | 87.4% | Not measured | Only Claude Sonnet 4.5 measured |
| LegalBench (Vals AI) | 84.1% | Not measured | Only Claude Sonnet 4.5 measured |
| CaseLaw (Vals AI) | 62.2% | Not measured | Only Claude Sonnet 4.5 measured |
| CorpFin (Vals AI) | 62.0% | Not measured | Only Claude Sonnet 4.5 measured |
| TaxEval (Vals AI) | 73.3% | Not measured | Only Claude Sonnet 4.5 measured |
| MortgageTax (Vals AI) | 64.0% | Not measured | Only Claude Sonnet 4.5 measured |
| MedQA (Vals AI) | 94.7% | Not measured | Only Claude Sonnet 4.5 measured |
| MedCode (Vals AI) | 44.1% | Not measured | Only Claude Sonnet 4.5 measured |
| SimpleQA Verified | 30.7% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: science | 1448 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: medicine and healthcare | 1444 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: legal and government | 1451 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: business and finance | 1440 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 4 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| Design Arena: websites | 1190 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: UI components | 1173 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: game dev | 1166 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: data viz | 1167 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: 3D | 1158 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: all code categories | 1183 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: SVG | 1114 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: ASCII art | 1204 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Claude Sonnet 4.5 | o3 Pro | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 36.1% | Not measured | Only Claude Sonnet 4.5 measured |
| MedScribe (Vals AI) | 84.5% | Not measured | Only Claude Sonnet 4.5 measured |
| DTBench | 83.2% | 86.9% | o3 Pro |
| LMCA | 38.8% | 38.5% | Claude Sonnet 4.5 |
| Fiction.LiveBench | Not measured | 97.2% | Only o3 Pro measured |
| Creative writing (Lech Mazur) | Not measured | 84.4% | Only o3 Pro measured |
| LMArena Text | 1438 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: instruction following | 1459 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: creative writing | 1442 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: English | 1450 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: non-English | 1425 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Chinese | 1460 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: German | 1427 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Japanese | 1390 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Korean | 1402 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: French | 1459 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Spanish | 1458 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Russian | 1437 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Polish | 1423 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: multi-turn | 1465 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: longer queries | 1475 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: writing and language | 1442 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: entertainment and media | 1428 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Document | 1450 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 22 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 4.5 | 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
Claude Sonnet 4.5 costs less
Repository review
50K input + 3K output tokens
Claude Sonnet 4.5 costs less
Agent loop
200K input + 10K output tokens
Claude Sonnet 4.5 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 | Anthropic Claude Sonnet 4.5 | OpenAI o3 Pro |
|---|---|---|
| Maker | Anthropic | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 29, 2025 | June 10, 2025 |
| Context window | 1M | 200K |
| Input $/Mtok | $3.00 | $20.00 |
| Output $/Mtok | $15.00 | $80.00 |
| Coding index | 59.1 | 84.9 |
| Independent measurements behind it | 2 | 1 |
| Cost per solved task | $1.16 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 4.5 better than o3 Pro for coding?
Pick o3 Pro for coding: it scores 84.9 on the Vibe Coding Index against 59.1 for Claude Sonnet 4.5, though on 1 benchmark against 2. Pick Claude Sonnet 4.5 when output tokens cost 5.3x less, or when the context window is larger, 1M against 200K tokens.
Which is cheaper, Claude Sonnet 4.5 or o3 Pro?
Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; o3 Pro costs $20.00 and $80.00. Cost per solved task is known for Claude Sonnet 4.5 only.
Which has the bigger context window, Claude Sonnet 4.5 or o3 Pro?
Claude Sonnet 4.5, with 1M tokens against 200K.
How many benchmarks is the Claude Sonnet 4.5 vs o3 Pro comparison based on?
7 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 4.5's coding index rests on 2 independent benchmarks and o3 Pro's on 1. Where only one model has a result, the page says so instead of naming a winner.