Claude Sonnet 5.5 vs GPT-5 Nano
Claude Sonnet 5.5 leads GPT-5 Nano on the Artificial Analysis Intelligence Index, 56.0 to 13.0, and GPT-5 Nano costs 25.0x less per output token ($0.40 vs $10.00 per million). Updated October 22, 2026; 51 benchmarks have a result for both.
Claude Sonnet 5.5 or GPT-5 Nano: which to pick
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; GPT-5 Nano has none, so the two cannot be ranked on coding.
Pick GPT-5 Nano for output tokens 25.0x cheaper ($0.40 vs $10.00 per million).
- Shared results
- 51
- Claude Sonnet 5.5 only
- 45
- GPT-5 Nano only
- 36
- Like-for-like categories
- 7 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 13.0.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only GPT-5 Nano has a GPQA Diamond result, 63.4%.
Directional only
Math
AIME
No call
Only GPT-5 Nano has a AIME result, 81.2%.
Directional only
Knowledge
MMLU Pro
No call
Only GPT-5 Nano has a MMLU Pro result, 76.1%.
Directional only
Web design
Design Arena: websites
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 1327 against 1101.
Same board, both measured
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 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5 Nano
Claude Sonnet 5.5 $0.0070, GPT-5 Nano $0.0003 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5 Nano has the number, $0.109.
Directional only
At a glance
- Coding index
- Claude Sonnet 5.5 87.3 from 5 benchmarks, GPT-5 Nano not benchmarked.
- Widest category
- Math, 52.4 points apart on average over 6 shared benchmarks.
- Widest single gap
- ProofBench: Claude Sonnet 5.5 100.0% against GPT-5 Nano 12.0%, 88.0 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 5.5 $10.00 against GPT-5 Nano $0.40 per million output tokens, 25.0x apart.
- Context window
- Claude Sonnet 5.5 takes 1M tokens, GPT-5 Nano 400K.
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 | GPT-5 Nano | Ties |
|---|---|---|---|---|
| Coding | 2 | 0 | ||
| Intelligence | 2 | 0 | ||
| Reasoning | 9 | 0 | ||
| Math | 6 | 0 | ||
| Knowledge | 6 | 0 | ||
| Web design | 6 | 0 | ||
| General | 20 | 0 | ||
| All shared boards | 51 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index20
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 34.8% | Only GPT-5 Nano measured |
| LiveBench coding | 94.7% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev | 1768 | Not measured | Only Claude Sonnet 5.5 measured |
| LiveCodeBench (Vals AI) | Not measured | 70.2% | Only GPT-5 Nano 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 | 78.9% | Only GPT-5 Nano measured |
| SciCode | 61.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 17.4% | Only GPT-5 Nano measured |
| Terminal-Bench | Not measured | 21.8% | Only GPT-5 Nano measured |
| FrontierCode | 52.1% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierSWE | 61.9% | Not measured | Only Claude Sonnet 5.5 measured |
| WeirdML | Not measured | 38.1% | Only GPT-5 Nano measured |
| ALE-Bench | 1819.1 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: coding | 1513 | 1351 | Claude Sonnet 5.5 |
| LMArena Text: software and IT | 1504 | 1345 | 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 |
| SciCode | 13.8% | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 13 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | Leader |
|---|---|---|---|
| AA Intelligence Index | 56.0 | 13.0 | Claude Sonnet 5.5 |
| Epoch Capabilities Index | 166.2 | 139.2 | Claude Sonnet 5.5 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index20 boards, none shared
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1305 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: agents building mobile apps | 1262 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: spreadsheets | 1273 | 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 | 36.5% | Only GPT-5 Nano measured |
| APEX-Agents | 75.5% | Not measured | Only Claude Sonnet 5.5 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 |
| Berkeley Function Calling Leaderboard (BFCL) | Not measured | 51.4% | Only GPT-5 Nano measured |
| Neither model has a result on the other 21 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 63.4% | Only GPT-5 Nano measured |
| 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 |
| MMMU Pro (Vals AI) | Not measured | 70.9% | Only GPT-5 Nano measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 67.6% | Only GPT-5 Nano measured |
| Humanity's Last Exam (Artificial Analysis run) | 55.0% | 9.5% | Claude Sonnet 5.5 |
| GPQA Diamond (Epoch AI run) | 95.6% | 69.4% | Claude Sonnet 5.5 |
| ARC-AGI | Not measured | 20.7% | Only GPT-5 Nano measured |
| ARC-AGI-2 | Not measured | 2.6% | Only GPT-5 Nano measured |
| Chess puzzles | 59.0% | 22.0% | Claude Sonnet 5.5 |
| Mystery game puzzles | 65.0% | 9.0% | Claude Sonnet 5.5 |
| VPCT | Not measured | 37.2% | Only GPT-5 Nano measured |
| LMArena Text: hard prompts | 1494 | 1328 | Claude Sonnet 5.5 |
| LMArena Text: expert | 1531 | 1321 | Claude Sonnet 5.5 |
| LMArena Text: hard prompts in English | 1502 | 1338 | Claude Sonnet 5.5 |
| LMArena Vision: diagrams | 1329 | 1141 | Claude Sonnet 5.5 |
| LMArena Vision: homework | 1331 | 1157 | Claude Sonnet 5.5 |
| Kagi LLM Benchmark | Not measured | 62.2% | Only GPT-5 Nano measured |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | Leader |
|---|---|---|---|
| AIME | Not measured | 81.2% | Only GPT-5 Nano measured |
| MATH 500 (Vals AI) | Not measured | 93.8% | Only GPT-5 Nano measured |
| MGSM (Vals AI) | Not measured | 89.3% | Only GPT-5 Nano measured |
| AA Math Index | Not measured | 83.7 | Only GPT-5 Nano measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 83.7% | Only GPT-5 Nano measured |
| OTIS Mock AIME | 100.0% | 81.1% | Claude Sonnet 5.5 |
| FrontierMath, tiers 1 to 3 | 88.8% | 20.0% | Claude Sonnet 5.5 |
| FrontierMath, tier 4 | 80.5% | 2.4% | Claude Sonnet 5.5 |
| ProofBench | 100.0% | 12.0% | Claude Sonnet 5.5 |
| MATH level 5 | Not measured | 95.2% | Only GPT-5 Nano measured |
| LMArena Text: math | 1497 | 1317 | Claude Sonnet 5.5 |
| LMArena Text: mathematical work | 1510 | 1326 | Claude Sonnet 5.5 |
| Neither model has a result on the other 1 board here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 76.1% | Only GPT-5 Nano measured |
| LegalBench (Vals AI) | Not measured | 50.1% | Only GPT-5 Nano measured |
| CaseLaw (Vals AI) | Not measured | 52.6% | Only GPT-5 Nano measured |
| TaxEval (Vals AI) | Not measured | 67.4% | Only GPT-5 Nano measured |
| MortgageTax (Vals AI) | Not measured | 53.6% | Only GPT-5 Nano measured |
| MedQA (Vals AI) | Not measured | 93.3% | Only GPT-5 Nano measured |
| MedCode (Vals AI) | 52.9% | 30.4% | Claude Sonnet 5.5 |
| MMLU Pro (Artificial Analysis run) | Not measured | 78.0% | Only GPT-5 Nano measured |
| SimpleQA Verified | 46.5% | 11.7% | Claude Sonnet 5.5 |
| LMArena Text: science | 1483 | 1318 | Claude Sonnet 5.5 |
| LMArena Text: medicine and healthcare | 1464 | 1335 | Claude Sonnet 5.5 |
| LMArena Text: legal and government | 1483 | 1298 | Claude Sonnet 5.5 |
| LMArena Text: business and finance | 1468 | 1311 | Claude Sonnet 5.5 |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | Leader |
|---|---|---|---|
| Design Arena: websites | 1327 | 1101 | Claude Sonnet 5.5 |
| Design Arena: UI components | 1369 | 1064 | Claude Sonnet 5.5 |
| Design Arena: game dev | 1472 | 1044 | Claude Sonnet 5.5 |
| Design Arena: data viz | 1382 | 1056 | Claude Sonnet 5.5 |
| Design Arena: 3D | 1442 | 965 | Claude Sonnet 5.5 |
| Design Arena: all code categories | 1365 | 1084 | Claude Sonnet 5.5 |
| 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 index200
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | 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% | 30.4% | Claude Sonnet 5.5 |
| MedScribe (Vals AI) | 91.1% | 72.9% | Claude Sonnet 5.5 |
| IFBench | Not measured | 67.6% | Only GPT-5 Nano measured |
| Long context reasoning (AA-LCR) | 82.7% | 45.0% | Claude Sonnet 5.5 |
| DTBench | 97.3% | 62.7% | Claude Sonnet 5.5 |
| LMCA | 68.3% | 7.9% | Claude Sonnet 5.5 |
| Fiction.LiveBench | Not measured | 44.4% | Only GPT-5 Nano measured |
| Furniture assembly | 75.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text | 1473 | 1320 | Claude Sonnet 5.5 |
| LMArena Text: instruction following | 1492 | 1306 | Claude Sonnet 5.5 |
| LMArena Text: creative writing | 1467 | 1249 | Claude Sonnet 5.5 |
| LMArena Vision | 1287 | 1159 | Claude Sonnet 5.5 |
| LMArena Text: English | 1484 | 1321 | Claude Sonnet 5.5 |
| LMArena Text: non-English | 1456 | 1313 | Claude Sonnet 5.5 |
| LMArena Text: Chinese | 1535 | 1356 | Claude Sonnet 5.5 |
| LMArena Text: German | Not measured | 1327 | Only GPT-5 Nano measured |
| LMArena Text: Japanese | Not measured | 1227 | Only GPT-5 Nano measured |
| LMArena Text: Korean | Not measured | 1269 | Only GPT-5 Nano measured |
| LMArena Text: French | 1499 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: Spanish | 1451 | 1360 | Claude Sonnet 5.5 |
| LMArena Text: Russian | 1454 | 1296 | Claude Sonnet 5.5 |
| LMArena Text: Polish | Not measured | 1314 | Only GPT-5 Nano measured |
| LMArena Text: multi-turn | 1465 | 1311 | Claude Sonnet 5.5 |
| LMArena Text: longer queries | 1495 | 1312 | Claude Sonnet 5.5 |
| LMArena Text: writing and language | 1474 | 1283 | Claude Sonnet 5.5 |
| LMArena Text: entertainment and media | 1461 | 1268 | Claude Sonnet 5.5 |
| LMArena Vision: English | 1289 | 1170 | Claude Sonnet 5.5 |
| LMArena Vision: Chinese | Not measured | 1176 | Only GPT-5 Nano measured |
| LMArena Vision: reading text | 1297 | 1152 | Claude Sonnet 5.5 |
| LMArena Vision: humor | Not measured | 1110 | Only GPT-5 Nano measured |
| LMArena Vision: creative writing | 1242 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 12 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 5.5 | GPT-5 Nano | 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
GPT-5 Nano costs less
Repository review
50K input + 3K output tokens
GPT-5 Nano costs less
Agent loop
200K input + 10K output tokens
GPT-5 Nano 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 | OpenAI GPT-5 Nano |
|---|---|---|
| Maker | Anthropic | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 28, 2026 | August 7, 2025 |
| Context window | 1M | 400K |
| Input $/Mtok | $2.00 | $0.05 |
| Output $/Mtok | $10.00 | $0.40 |
| Coding index | 87.3 | Not benchmarked |
| Independent measurements behind it | 5 | 0 |
| Cost per solved task | Not computable | $0.109 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 5.5 better than GPT-5 Nano for coding?
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; GPT-5 Nano has none, so the two cannot be ranked on coding. Pick GPT-5 Nano for output tokens 25.0x cheaper ($0.40 vs $10.00 per million).
Which is cheaper, Claude Sonnet 5.5 or GPT-5 Nano?
Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; GPT-5 Nano costs $0.05 and $0.40. Cost per solved task is known for GPT-5 Nano only.
Which has the bigger context window, Claude Sonnet 5.5 or GPT-5 Nano?
Claude Sonnet 5.5, with 1M tokens against 400K.
How many benchmarks is the Claude Sonnet 5.5 vs GPT-5 Nano comparison based on?
51 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 5.5's coding index rests on 5 independent benchmarks and GPT-5 Nano's on 0. Where only one model has a result, the page says so instead of naming a winner.