Claude Sonnet 5.5 vs Phi 4
Claude Sonnet 5.5 leads Phi 4 on the Artificial Analysis Intelligence Index, 56.0 to 5.9, and Phi 4 costs 71.4x less per output token ($0.14 vs $10.00 per million). Updated October 21, 2026; 30 benchmarks have a result for both.
vs boards won of 30 shared
Claude Sonnet 5.5 or Phi 4: which to pick
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; Phi 4 has none, so the two cannot be ranked on coding.
Pick Phi 4 for output tokens 71.4x cheaper ($0.14 vs $10.00 per million).
Model AClaude Sonnet 5.5Anthropic87.3/1005 independent benchmarksNo cost per solved taskModel BPhi 4MicrosoftNot benchmarkedNo coding benchmarkNo cost per solved task
- Shared results
- 30
- Claude Sonnet 5.5 only
- 65
- Phi 4 only
- 15
- Like-for-like categories
- 6 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
Only Claude Sonnet 5.5 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 56.0 against 5.9.
Same board, both measured
Web design
Design Arena: websites
No call
Only Claude Sonnet 5.5 has a Design Arena: websites result, 1326.
Directional only
General
Vals Index
No call
Only Claude Sonnet 5.5 has a Vals Index result, 70.8%.
Directional only
Long documents
Listed context window
Claude Sonnet 5.5
Claude Sonnet 5.5 takes 1M tokens against 16K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Phi 4
Claude Sonnet 5.5 $0.0070, Phi 4 $0.0001 per turn.
List prices
At a glance
- Coding index
- Claude Sonnet 5.5 87.3 from 5 benchmarks, Phi 4 not benchmarked.
- Widest category
- Math, 56.9 points apart on average over 3 shared benchmarks.
- Widest single gap
- OTIS Mock AIME: Claude Sonnet 5.5 100.0% against Phi 4 13.8%, 86.3 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 5.5 $10.00 against Phi 4 $0.14 per million output tokens, 71.4x apart.
- Context window
- Claude Sonnet 5.5 takes 1M tokens, Phi 4 16K.
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 5.5 | Bars | Phi 4 | Ties |
|---|---|---|---|---|
| Coding | 2 | 0 | ||
| Intelligence | 2 | 0 | ||
| Reasoning | 5 | 0 | ||
| Math | 3 | 0 | ||
| Knowledge | 4 | 0 | ||
| General | 14 | 0 | ||
| All shared boards | 30 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index20
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| LiveBench coding | 94.7% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev | 1768 | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 4 (Vals AI) | 64.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Vibe Code Bench (Vals AI) | 92.4% | Not measured | Only Claude Sonnet 5.5 measured |
| Code migration (Vals AI) | 69.8% | Not measured | Only Claude Sonnet 5.5 measured |
| ProgramBench (Vals AI) | 6.5% | Not measured | Only Claude Sonnet 5.5 measured |
| IOI (Vals AI) | 83.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 2.1 (Vals AI) | 83.2% | Not measured | Only Claude Sonnet 5.5 measured |
| SWE-bench Multimodal (Vals AI) | 58.3% | Not measured | Only Claude Sonnet 5.5 measured |
| CyberBench (Vals AI) | 59.6% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 23.1% | Only Phi 4 measured |
| SciCode | 61.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 3.8% | Only Phi 4 measured |
| FrontierCode | 52.1% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierSWE | 61.9% | Not measured | Only Claude Sonnet 5.5 measured |
| ALE-Bench | 1819.1 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: coding | 1513 | 1231 | Claude Sonnet 5.5 |
| LMArena Text: software and IT | 1504 | 1228 | Claude Sonnet 5.5 |
| LMArena WebDev: React | 1817 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev: HTML | 1741 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev: from an image | 1737 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 17 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| AA Intelligence Index | 56.0 | 5.9 | Claude Sonnet 5.5 |
| Epoch Capabilities Index | 166.2 | 130.5 | Claude Sonnet 5.5 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index20 boards, none shared
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1306 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: agents building mobile apps | 1257 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: spreadsheets | 1244 | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench research | 83.6% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench browser | 84.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench long agentic | 78.8% | Not measured | Only Claude Sonnet 5.5 measured |
| SREBench (Vals AI) | 30.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Finance Agent (Vals AI) | 58.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Tax Agent Bench (Vals AI) | 42.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Legal Research Bench (Vals AI) | 48.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 10.4% | Not measured | Only Claude Sonnet 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 75.7% | Not measured | Only Claude Sonnet 5.5 measured |
| BioMysteryBench (Vals AI) | 81.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench-Science (Vals AI) | 47.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Vals Science Index | 59.1% | Not measured | Only Claude Sonnet 5.5 measured |
| τ²-Bench Telecom | Not measured | 0.0% | Only Phi 4 measured |
| APEX-Agents | 75.5% | Not measured | Only Claude Sonnet 5.5 measured |
| BALROG | Not measured | 11.6% | Only Phi 4 measured |
| SpireClimb | 1.3% | Not measured | Only Claude Sonnet 5.5 measured |
| Vending-Bench 2 | $11,165 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 19 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| LiveBench reasoning | 91.6% | Not measured | Only Claude Sonnet 5.5 measured |
| MysteryMechanism (Vals AI) | 49.1% | Not measured | Only Claude Sonnet 5.5 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 57.5% | Only Phi 4 measured |
| Humanity's Last Exam (Artificial Analysis run) | 55.0% | 3.8% | Claude Sonnet 5.5 |
| GPQA Diamond (Epoch AI run) | 95.6% | 56.1% | Claude Sonnet 5.5 |
| Chess puzzles | 59.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Mystery game puzzles | 65.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: hard prompts | 1494 | 1220 | Claude Sonnet 5.5 |
| LMArena Text: expert | 1531 | 1203 | Claude Sonnet 5.5 |
| LMArena Text: hard prompts in English | 1502 | 1230 | Claude Sonnet 5.5 |
| LMArena Vision: diagrams | 1329 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Vision: homework | 1331 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 9 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| AA Math Index | Not measured | 18.0 | Only Phi 4 measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 18.0% | Only Phi 4 measured |
| OTIS Mock AIME | 100.0% | 13.8% | Claude Sonnet 5.5 |
| FrontierMath, tiers 1 to 3 | 88.8% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierMath, tier 4 | 80.5% | Not measured | Only Claude Sonnet 5.5 measured |
| ProofBench | 100.0% | Not measured | Only Claude Sonnet 5.5 measured |
| MATH level 5 | Not measured | 64.9% | Only Phi 4 measured |
| LMArena Text: math | 1497 | 1246 | Claude Sonnet 5.5 |
| LMArena Text: mathematical work | 1510 | 1254 | Claude Sonnet 5.5 |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| MedCode (Vals AI) | 52.9% | Not measured | Only Claude Sonnet 5.5 measured |
| MMLU Pro (Artificial Analysis run) | Not measured | 71.4% | Only Phi 4 measured |
| SimpleQA Verified | 46.5% | Not measured | Only Claude Sonnet 5.5 measured |
| MMLU | Not measured | 84.8% | Only Phi 4 measured |
| LMArena Text: science | 1483 | 1206 | Claude Sonnet 5.5 |
| LMArena Text: medicine and healthcare | 1464 | 1202 | Claude Sonnet 5.5 |
| LMArena Text: legal and government | 1483 | 1241 | Claude Sonnet 5.5 |
| LMArena Text: business and finance | 1468 | 1199 | Claude Sonnet 5.5 |
| Neither model has a result on the other 9 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| Design Arena: websites | 1326 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: UI components | 1365 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: game dev | 1469 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: data viz | 1394 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: 3D | 1452 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: all code categories | 1364 | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench design | 85.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 2 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index140
| Benchmark | Claude Sonnet 5.5 | Phi 4 | Leader |
|---|---|---|---|
| Vals Index | 70.8% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench data analysis | 59.5% | Not measured | Only Claude Sonnet 5.5 measured |
| Public Benefits Bench (Vals AI) | 67.2% | Not measured | Only Claude Sonnet 5.5 measured |
| SAGE (Vals AI) | 51.8% | Not measured | Only Claude Sonnet 5.5 measured |
| MedScribe (Vals AI) | 91.1% | Not measured | Only Claude Sonnet 5.5 measured |
| IFBench | Not measured | 23.5% | Only Phi 4 measured |
| Long context reasoning (AA-LCR) | 82.7% | 0.0% | Claude Sonnet 5.5 |
| DTBench | 97.3% | Not measured | Only Claude Sonnet 5.5 measured |
| LMCA | 68.3% | Not measured | Only Claude Sonnet 5.5 measured |
| Creative writing (Lech Mazur) | Not measured | 62.6% | Only Phi 4 measured |
| Furniture assembly | 75.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text | 1473 | 1217 | Claude Sonnet 5.5 |
| LMArena Text: instruction following | 1492 | 1201 | Claude Sonnet 5.5 |
| LMArena Text: creative writing | 1467 | 1181 | Claude Sonnet 5.5 |
| LMArena Vision | 1287 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: English | 1484 | 1231 | Claude Sonnet 5.5 |
| LMArena Text: non-English | 1456 | 1197 | Claude Sonnet 5.5 |
| LMArena Text: Chinese | 1535 | 1212 | Claude Sonnet 5.5 |
| LMArena Text: German | Not measured | 1222 | Only Phi 4 measured |
| LMArena Text: Japanese | Not measured | 1158 | Only Phi 4 measured |
| LMArena Text: Korean | Not measured | 1151 | Only Phi 4 measured |
| LMArena Text: French | 1499 | 1224 | Claude Sonnet 5.5 |
| LMArena Text: Spanish | 1451 | 1234 | Claude Sonnet 5.5 |
| LMArena Text: Russian | 1454 | 1209 | Claude Sonnet 5.5 |
| LMArena Text: multi-turn | 1465 | 1206 | Claude Sonnet 5.5 |
| LMArena Text: longer queries | 1495 | 1217 | Claude Sonnet 5.5 |
| LMArena Text: writing and language | 1474 | 1198 | Claude Sonnet 5.5 |
| LMArena Text: entertainment and media | 1461 | 1162 | Claude Sonnet 5.5 |
| LMArena Vision: English | 1289 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Vision: reading text | 1297 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Vision: creative writing | 1242 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 5.5 | Phi 4 | 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 5.5$0.0070Fits in one request
Phi 4$0.0001Fits in one request
Phi 4 costs less
Repository review
50K input + 3K output tokens
Claude Sonnet 5.5$0.130Fits in one request
Phi 4$0.0039Exceeds the context window
Phi 4 costs less
Agent loop
200K input + 10K output tokens
Claude Sonnet 5.5$0.500Fits in one request
Phi 4$0.015Exceeds the context window
Phi 4 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 5.5 | Microsoft Phi 4 |
|---|---|---|
| Maker | Anthropic | Microsoft |
| Weights | No public weights listed | Open weights |
| Released | September 28, 2026 | January 10, 2025 |
| Context window | 1M | 16K |
| Input $/Mtok | $2.00 | $0.07 |
| Output $/Mtok | $10.00 | $0.14 |
| Coding index | 87.3 | Not benchmarked |
| Independent measurements behind it | 5 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 5.5 better than Phi 4 for coding?
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; Phi 4 has none, so the two cannot be ranked on coding. Pick Phi 4 for output tokens 71.4x cheaper ($0.14 vs $10.00 per million).
Which is cheaper, Claude Sonnet 5.5 or Phi 4?
Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; Phi 4 costs $0.07 and $0.14. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Sonnet 5.5 or Phi 4?
Claude Sonnet 5.5, with 1M tokens against 16K.
How many benchmarks is the Claude Sonnet 5.5 vs Phi 4 comparison based on?
30 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 5.5's coding index rests on 5 independent benchmarks and Phi 4's on 0. Where only one model has a result, the page says so instead of naming a winner.