Claude Haiku 5.5 vs Claude Sonnet 4.5
Updated October 21, 2026. 29 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
vs boards won of 29 shared
Decision reading
Pick Claude Haiku 5.5 for coding: it scores 75.9 on the Vibe Coding Index against 59.1 for Claude Sonnet 4.5.
Pick Claude Sonnet 4.5 when what matters is Vending-Bench 2 or SimpleQA Verified, where it leads.
Model AClaude Haiku 5.5Anthropic75.9/1002 independent benchmarksNo cost per solved taskModel BClaude Sonnet 4.5Anthropic59.1/1002 independent benchmarks$1.16 per solved task
- Shared results
- 29
- Claude Haiku 5.5 only
- 33
- Claude Sonnet 4.5 only
- 63
- Like-for-like categories
- 8 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
Claude Haiku 5.5
Claude Haiku 5.5 scores 75.9 against 59.1.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Haiku 5.5
Claude Haiku 5.5 leads, 43.4 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
Claude Haiku 5.5
Claude Haiku 5.5 leads, 1263 against 1190.
Same board, both measured
General
Vals Index
No call
Only Claude Haiku 5.5 has a Vals Index result, 58.7%.
Directional only
Long documents
Listed context window
No call
Both take 1M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Claude Haiku 5.5
Claude Haiku 5.5 $0.0003, Claude Sonnet 4.5 $0.011 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 Haiku 5.5 75.9 from 2 benchmarks, Claude Sonnet 4.5 59.1 from 2 benchmarks.
- Widest category
- Math, 46.6 points apart on average over 4 shared benchmarks.
- Widest single gap
- ProofBench: Claude Haiku 5.5 89.0% against Claude Sonnet 4.5 19.0%, 70.0 points apart on a 0 to 100 scale.
- Output price
- Claude Haiku 5.5 $0.50 against Claude Sonnet 4.5 $15.00 per million output tokens, 30.0x apart.
- Context window
- Both take 1M tokens.
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 Haiku 5.5 | Bars | Claude Sonnet 4.5 | Ties |
|---|---|---|---|---|
| Coding | 4 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 0 | 1 | ||
| Reasoning | 6 | 0 | ||
| Math | 4 | 0 | ||
| Knowledge | 1 | 1 | ||
| Web design | 6 | 0 | ||
| General | 4 | 0 | ||
| All shared boards | 27 | 2 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index40
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 74.8% | Only Claude Sonnet 4.5 measured |
| SWE-bench Multilingual | Not measured | 67.0% | Only Claude Sonnet 4.5 measured |
| LiveBench coding | 91.4% | Not measured | Only Claude Haiku 5.5 measured |
| LMArena WebDev | 1586 | 1394 | Claude Haiku 5.5 |
| AA Coding Index | Not measured | 52.1 | Only Claude Sonnet 4.5 measured |
| LiveCodeBench (Vals AI) | Not measured | 73.0% | Only Claude Sonnet 4.5 measured |
| SWE-bench Verified (Vals AI) | Not measured | 70.0% | Only Claude Sonnet 4.5 measured |
| Terminal-Bench 4 (Vals AI) | 36.4% | Not measured | Only Claude Haiku 5.5 measured |
| Vibe Code Bench (Vals AI) | 90.4% | 22.6% | Claude Haiku 5.5 |
| Code migration (Vals AI) | 44.6% | Not measured | Only Claude Haiku 5.5 measured |
| ProgramBench (Vals AI) | 2.5% | Not measured | Only Claude Haiku 5.5 measured |
| IOI (Vals AI) | 47.3% | Not measured | Only Claude Haiku 5.5 measured |
| SWE-bench Multimodal (Vals AI) | 44.0% | Not measured | Only Claude Haiku 5.5 measured |
| Vibe Code Bench 1-100 (Vals AI) | 20.4% | Not measured | Only Claude Haiku 5.5 measured |
| CyberBench (Vals AI) | 75.5% | Not measured | Only Claude Haiku 5.5 measured |
| SciCode | 55.0% | Not measured | Only Claude Haiku 5.5 measured |
| Terminal-Bench | Not measured | 46.5% | Only Claude Sonnet 4.5 measured |
| FrontierCode | 46.4% | Not measured | Only Claude Haiku 5.5 measured |
| FrontierSWE | 43.8% | Not measured | Only Claude Haiku 5.5 measured |
| GSO-Bench | Not measured | 14.7% | Only Claude Sonnet 4.5 measured |
| WeirdML | Not measured | 47.7% | Only Claude Sonnet 4.5 measured |
| Cybench | Not measured | 60.0% | Only Claude Sonnet 4.5 measured |
| LMArena Text: coding | Not measured | 1488 | Only Claude Sonnet 4.5 measured |
| LMArena Text: software and IT | Not measured | 1473 | Only Claude Sonnet 4.5 measured |
| LMArena WebDev: React | 1605 | 1386 | Claude Haiku 5.5 |
| LMArena WebDev: HTML | 1569 | 1399 | Claude Haiku 5.5 |
| Neither model has a result on the other 12 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 43.4 | 20.7 | Claude Haiku 5.5 |
| Epoch Capabilities Index | 159.3 | 146.7 | Claude Haiku 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 15.8 | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building web apps | Not measured | 1060 | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building full-stack apps | Not measured | 1050 | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building mobile apps | Not measured | 1137 | Only Claude Sonnet 4.5 measured |
| LiveBench research | 81.9% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench browser | 80.0% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench long agentic | 57.6% | Not measured | Only Claude Haiku 5.5 measured |
| SREBench (Vals AI) | 5.7% | Not measured | Only Claude Haiku 5.5 measured |
| Finance Agent (Vals AI) | 54.1% | Not measured | Only Claude Haiku 5.5 measured |
| Tax Agent Bench (Vals AI) | 31.9% | Not measured | Only Claude Haiku 5.5 measured |
| Legal Research Bench (Vals AI) | 43.3% | Not measured | Only Claude Haiku 5.5 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 4.2% | Not measured | Only Claude Haiku 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 59.0% | Not measured | Only Claude Haiku 5.5 measured |
| BioMysteryBench (Vals AI) | 70.4% | Not measured | Only Claude Haiku 5.5 measured |
| Terminal-Bench-Science (Vals AI) | 10.0% | Not measured | Only Claude Haiku 5.5 measured |
| Vals Science Index | 38.5% | Not measured | Only Claude Haiku 5.5 measured |
| APEX-Agents | 56.1% | Not measured | Only Claude Haiku 5.5 measured |
| METR time horizons | Not measured | 67.4% | Only Claude Sonnet 4.5 measured |
| Remote Labor Index | Not measured | 2.1% | Only Claude Sonnet 4.5 measured |
| GDPval | Not measured | 42.5% | Only Claude Sonnet 4.5 measured |
| DeepResearch Bench | Not measured | 52.6% | Only Claude Sonnet 4.5 measured |
| OSWorld | Not measured | 62.9% | Only Claude Sonnet 4.5 measured |
| Vending-Bench 2 | $3,602 | $3,839 | Claude Sonnet 4.5 |
| Neither model has a result on the other 16 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 81.6% | Only Claude Sonnet 4.5 measured |
| LiveBench reasoning | 82.4% | Not measured | Only Claude Haiku 5.5 measured |
| MysteryMechanism (Vals AI) | 35.1% | Not measured | Only Claude Haiku 5.5 measured |
| MMMU Pro (Vals AI) | Not measured | 79.3% | Only Claude Sonnet 4.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 44.4% | Not measured | Only Claude Haiku 5.5 measured |
| GPQA Diamond (Epoch AI run) | 89.6% | 82.3% | Claude Haiku 5.5 |
| ARC-AGI | 89.0% | 63.7% | Claude Haiku 5.5 |
| ARC-AGI-2 | 61.3% | 13.6% | Claude Haiku 5.5 |
| SimpleBench | Not measured | 54.3% | Only Claude Sonnet 4.5 measured |
| Chess puzzles | 55.0% | 10.0% | Claude Haiku 5.5 |
| Mystery game puzzles | 30.0% | 17.0% | Claude Haiku 5.5 |
| EBR-bench | 43.8% | 2.4% | Claude Haiku 5.5 |
| VPCT | Not measured | 39.8% | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts | Not measured | 1462 | Only Claude Sonnet 4.5 measured |
| LMArena Text: expert | Not measured | 1483 | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts in English | Not measured | 1471 | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AIME | Not measured | 88.2% | Only Claude Sonnet 4.5 measured |
| MGSM (Vals AI) | Not measured | 94.3% | Only Claude Sonnet 4.5 measured |
| OTIS Mock AIME | 98.9% | 77.8% | Claude Haiku 5.5 |
| FrontierMath, tiers 1 to 3 | 75.1% | 23.9% | Claude Haiku 5.5 |
| FrontierMath, tier 4 | 46.3% | 2.4% | Claude Haiku 5.5 |
| ProofBench | 89.0% | 19.0% | Claude Haiku 5.5 |
| MATH level 5 | Not measured | 97.7% | Only Claude Sonnet 4.5 measured |
| LMArena Text: math | Not measured | 1449 | Only Claude Sonnet 4.5 measured |
| LMArena Text: mathematical work | Not measured | 1462 | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 87.4% | Only Claude Sonnet 4.5 measured |
| LegalBench (Vals AI) | Not measured | 84.1% | Only Claude Sonnet 4.5 measured |
| CaseLaw (Vals AI) | Not measured | 62.2% | Only Claude Sonnet 4.5 measured |
| CorpFin (Vals AI) | Not measured | 62.0% | Only Claude Sonnet 4.5 measured |
| TaxEval (Vals AI) | Not measured | 73.3% | Only Claude Sonnet 4.5 measured |
| MortgageTax (Vals AI) | Not measured | 64.0% | Only Claude Sonnet 4.5 measured |
| MedQA (Vals AI) | Not measured | 94.7% | Only Claude Sonnet 4.5 measured |
| MedCode (Vals AI) | 51.5% | 44.1% | Claude Haiku 5.5 |
| SimpleQA Verified | 23.8% | 30.7% | Claude Sonnet 4.5 |
| LMArena Text: science | Not measured | 1448 | Only Claude Sonnet 4.5 measured |
| LMArena Text: medicine and healthcare | Not measured | 1444 | Only Claude Sonnet 4.5 measured |
| LMArena Text: legal and government | Not measured | 1451 | Only Claude Sonnet 4.5 measured |
| LMArena Text: business and finance | Not measured | 1440 | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 4 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| Design Arena: websites | 1263 | 1190 | Claude Haiku 5.5 |
| Design Arena: UI components | 1295 | 1173 | Claude Haiku 5.5 |
| Design Arena: game dev | 1315 | 1166 | Claude Haiku 5.5 |
| Design Arena: data viz | 1292 | 1167 | Claude Haiku 5.5 |
| Design Arena: 3D | 1343 | 1158 | Claude Haiku 5.5 |
| Design Arena: all code categories | 1279 | 1183 | Claude Haiku 5.5 |
| Design Arena: SVG | Not measured | 1114 | Only Claude Sonnet 4.5 measured |
| Design Arena: ASCII art | Not measured | 1204 | Only Claude Sonnet 4.5 measured |
| LiveBench design | 83.1% | Not measured | Only Claude Haiku 5.5 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| Vals Index | 58.7% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench data analysis | 53.1% | Not measured | Only Claude Haiku 5.5 measured |
| Public Benefits Bench (Vals AI) | 63.2% | Not measured | Only Claude Haiku 5.5 measured |
| SAGE (Vals AI) | 45.8% | 36.1% | Claude Haiku 5.5 |
| MedScribe (Vals AI) | 89.5% | 84.5% | Claude Haiku 5.5 |
| Long context reasoning (AA-LCR) | 82.7% | Not measured | Only Claude Haiku 5.5 measured |
| DTBench | 95.0% | 83.2% | Claude Haiku 5.5 |
| LMCA | 51.1% | 38.8% | Claude Haiku 5.5 |
| Furniture assembly | 47.5% | Not measured | Only Claude Haiku 5.5 measured |
| LMArena Text | Not measured | 1438 | Only Claude Sonnet 4.5 measured |
| LMArena Text: instruction following | Not measured | 1459 | Only Claude Sonnet 4.5 measured |
| LMArena Text: creative writing | Not measured | 1442 | Only Claude Sonnet 4.5 measured |
| LMArena Text: English | Not measured | 1450 | Only Claude Sonnet 4.5 measured |
| LMArena Text: non-English | Not measured | 1425 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Chinese | Not measured | 1460 | Only Claude Sonnet 4.5 measured |
| LMArena Text: German | Not measured | 1427 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Japanese | Not measured | 1390 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Korean | Not measured | 1402 | Only Claude Sonnet 4.5 measured |
| LMArena Text: French | Not measured | 1459 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Spanish | Not measured | 1458 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Russian | Not measured | 1437 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Polish | Not measured | 1423 | Only Claude Sonnet 4.5 measured |
| LMArena Text: multi-turn | Not measured | 1465 | Only Claude Sonnet 4.5 measured |
| LMArena Text: longer queries | Not measured | 1475 | Only Claude Sonnet 4.5 measured |
| LMArena Text: writing and language | Not measured | 1442 | Only Claude Sonnet 4.5 measured |
| LMArena Text: entertainment and media | Not measured | 1428 | Only Claude Sonnet 4.5 measured |
| LMArena Document | Not measured | 1450 | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 19 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Haiku 5.5 | Claude Sonnet 4.5 | 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 Haiku 5.5$0.0003Fits in one request
Claude Sonnet 4.5$0.011Fits in one request
Claude Haiku 5.5 costs less
Repository review
50K input + 3K output tokens
Claude Haiku 5.5$0.0065Fits in one request
Claude Sonnet 4.5$0.195Fits in one request
Claude Haiku 5.5 costs less
Agent loop
200K input + 10K output tokens
Claude Haiku 5.5$0.025Fits in one request
Claude Sonnet 4.5$0.750Fits in one request
Claude Haiku 5.5 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 Haiku 5.5 | Anthropic Claude Sonnet 4.5 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Weights | No public weights listed | No public weights listed |
| Released | October 7, 2026 | September 29, 2025 |
| Context window | 1M | 1M |
| Input $/Mtok | $0.10 | $3.00 |
| Output $/Mtok | $0.50 | $15.00 |
| Coding index | 75.9 | 59.1 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | Not computable | $1.16 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Haiku 5.5 better than Claude Sonnet 4.5 for coding?
Pick Claude Haiku 5.5 for coding: it scores 75.9 on the Vibe Coding Index against 59.1 for Claude Sonnet 4.5. Pick Claude Sonnet 4.5 when what matters is Vending-Bench 2 or SimpleQA Verified, where it leads.
Which is cheaper, Claude Haiku 5.5 or Claude Sonnet 4.5?
Claude Haiku 5.5 costs $0.10 per million input tokens and $0.50 per million output tokens; Claude Sonnet 4.5 costs $3.00 and $15.00. Cost per solved task is known for Claude Sonnet 4.5 only.
Which has the bigger context window, Claude Haiku 5.5 or Claude Sonnet 4.5?
Neither: both take 1M tokens.
How many benchmarks is the Claude Haiku 5.5 vs Claude Sonnet 4.5 comparison based on?
29 benchmarks have a result for both models as of October 21, 2026. Claude Haiku 5.5's coding index rests on 2 independent benchmarks and Claude Sonnet 4.5's on 2. Where only one model has a result, the page says so instead of naming a winner.