Claude Sonnet 5.5 vs DeepSeek V4 Pro 0423
Claude Sonnet 5.5 leads DeepSeek V4 Pro 0423 on coding, 87.3 to 38.7 on the Vibe Coding Index, and DeepSeek V4 Pro 0423 costs 3.4x less per output token ($2.976 vs $10.00 per million). Updated October 22, 2026; 61 benchmarks have a result for both.
Claude Sonnet 5.5 or DeepSeek V4 Pro 0423: which to pick
Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 38.7 for DeepSeek V4 Pro 0423.
Pick DeepSeek V4 Pro 0423 for output tokens 3.4x cheaper ($2.976 vs $10.00 per million) and a larger context window (1.05M against 1M tokens).
- Shared results
- 61
- Claude Sonnet 5.5 only
- 35
- DeepSeek V4 Pro 0423 only
- 23
- Like-for-like categories
- 8 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
Claude Sonnet 5.5
Claude Sonnet 5.5 scores 87.3 against 38.7.
5 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 56.0 against 30.4.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only DeepSeek V4 Pro 0423 has a AA Agentic Index result, 26.3.
Directional only
Reasoning
GPQA Diamond
No call
Only DeepSeek V4 Pro 0423 has a GPQA Diamond result, 89.4%.
Directional only
Knowledge
MMLU Pro
No call
Only DeepSeek V4 Pro 0423 has a MMLU Pro result, 87.3%.
Directional only
Web design
Design Arena: websites
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 1326 against 1234.
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
DeepSeek V4 Pro 0423
DeepSeek V4 Pro 0423 takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V4 Pro 0423
Claude Sonnet 5.5 $0.0070, DeepSeek V4 Pro 0423 $0.0028 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only DeepSeek V4 Pro 0423 has the number, $0.57.
Directional only
At a glance
- Coding index
- Claude Sonnet 5.5 87.3 from 5 benchmarks, DeepSeek V4 Pro 0423 38.7 from 5 benchmarks.
- Widest category
- Math, 37.8 points apart on average over 6 shared benchmarks.
- Widest single gap
- ProofBench: Claude Sonnet 5.5 100.0% against DeepSeek V4 Pro 0423 16.0%, 84.0 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 5.5 $10.00 against DeepSeek V4 Pro 0423 $2.976 per million output tokens, 3.4x apart.
- Context window
- Claude Sonnet 5.5 takes 1M tokens, DeepSeek V4 Pro 0423 1.05M.
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 | DeepSeek V4 Pro 0423 | Ties |
|---|---|---|---|---|
| Coding | 12 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 6 | 0 | ||
| Reasoning | 6 | 0 | ||
| Math | 6 | 0 | ||
| Knowledge | 4 | 2 | ||
| Web design | 6 | 0 | ||
| General | 15 | 2 | ||
| All shared boards | 57 | 4 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index120
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | Leader |
|---|---|---|---|
| LiveBench coding | 94.7% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev | 1768 | 1447 | Claude Sonnet 5.5 |
| AA Coding Index | Not measured | 59.4 | Only DeepSeek V4 Pro 0423 measured |
| LiveCodeBench (Vals AI) | Not measured | 87.5% | Only DeepSeek V4 Pro 0423 measured |
| SWE-bench Verified (Vals AI) | Not measured | 77.4% | Only DeepSeek V4 Pro 0423 measured |
| Terminal-Bench 4 (Vals AI) | 64.1% | 11.1% | Claude Sonnet 5.5 |
| Vibe Code Bench (Vals AI) | 92.4% | 49.9% | Claude Sonnet 5.5 |
| Code migration (Vals AI) | 69.8% | 26.2% | Claude Sonnet 5.5 |
| ProgramBench (Vals AI) | 6.5% | 0.0% | Claude Sonnet 5.5 |
| IOI (Vals AI) | 83.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 2.1 (Vals AI) | 83.2% | 50.2% | Claude Sonnet 5.5 |
| SWE-bench Multimodal (Vals AI) | 58.3% | Not measured | Only Claude Sonnet 5.5 measured |
| SkillsBench (Vals AI) | Not measured | 51.3% | Only DeepSeek V4 Pro 0423 measured |
| CyberBench (Vals AI) | 59.6% | Not measured | Only Claude Sonnet 5.5 measured |
| SciCode | 61.0% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierCode | 52.1% | 17.6% | Claude Sonnet 5.5 |
| FrontierSWE | 61.9% | Not measured | Only Claude Sonnet 5.5 measured |
| WeirdML | Not measured | 48.9% | Only DeepSeek V4 Pro 0423 measured |
| ALE-Bench | 1819.1 | 1006.1 | Claude Sonnet 5.5 |
| LMArena Text: coding | 1513 | 1470 | Claude Sonnet 5.5 |
| LMArena Text: software and IT | 1504 | 1469 | Claude Sonnet 5.5 |
| LMArena WebDev: React | 1817 | 1441 | Claude Sonnet 5.5 |
| LMArena WebDev: HTML | 1741 | 1435 | Claude Sonnet 5.5 |
| 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 14 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | Leader |
|---|---|---|---|
| AA Intelligence Index | 56.0 | 30.4 | Claude Sonnet 5.5 |
| Epoch Capabilities Index | 166.2 | 149.1 | Claude Sonnet 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 26.3 | Only DeepSeek V4 Pro 0423 measured |
| Design Arena: agents building web apps | 1305 | 1000 | Claude Sonnet 5.5 |
| Design Arena: agents building full-stack apps | Not measured | 948 | Only DeepSeek V4 Pro 0423 measured |
| Design Arena: agents building mobile apps | 1260 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: agents building Godot games | Not measured | 1059 | Only DeepSeek V4 Pro 0423 measured |
| Design Arena: spreadsheets | 1260 | 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% | 44.1% | Claude Sonnet 5.5 |
| Tax Agent Bench (Vals AI) | 42.0% | 25.2% | Claude Sonnet 5.5 |
| Legal Research Bench (Vals AI) | 48.1% | 23.1% | Claude Sonnet 5.5 |
| Harvey's Legal Agent Benchmark (Vals AI) | 10.4% | Not measured | Only Claude Sonnet 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 75.7% | 51.6% | Claude Sonnet 5.5 |
| 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 |
| 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 | $3,285 | Claude Sonnet 5.5 |
| Neither model has a result on the other 20 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 89.4% | Only DeepSeek V4 Pro 0423 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 |
| Humanity's Last Exam (Artificial Analysis run) | 55.0% | Not measured | Only Claude Sonnet 5.5 measured |
| GPQA Diamond (Epoch AI run) | 95.6% | 90.9% | Claude Sonnet 5.5 |
| Chess puzzles | 59.0% | 19.0% | Claude Sonnet 5.5 |
| Mystery game puzzles | 65.0% | 17.0% | Claude Sonnet 5.5 |
| LMArena Text: hard prompts | 1494 | 1461 | Claude Sonnet 5.5 |
| LMArena Text: expert | 1531 | 1463 | Claude Sonnet 5.5 |
| LMArena Text: hard prompts in English | 1502 | 1466 | 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 |
| Kagi LLM Benchmark | Not measured | 53.5% | Only DeepSeek V4 Pro 0423 measured |
| Neither model has a result on the other 9 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | 96.7% | Claude Sonnet 5.5 |
| FrontierMath, tiers 1 to 3 | 88.8% | 45.3% | Claude Sonnet 5.5 |
| FrontierMath, tier 4 | 80.5% | 2.4% | Claude Sonnet 5.5 |
| ProofBench | 100.0% | 16.0% | Claude Sonnet 5.5 |
| LMArena Text: math | 1497 | 1443 | Claude Sonnet 5.5 |
| LMArena Text: mathematical work | 1510 | 1455 | Claude Sonnet 5.5 |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index42
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 87.3% | Only DeepSeek V4 Pro 0423 measured |
| LegalBench (Vals AI) | Not measured | 80.3% | Only DeepSeek V4 Pro 0423 measured |
| CaseLaw (Vals AI) | Not measured | 59.4% | Only DeepSeek V4 Pro 0423 measured |
| CorpFin (Vals AI) | Not measured | 61.4% | Only DeepSeek V4 Pro 0423 measured |
| TaxEval (Vals AI) | Not measured | 72.1% | Only DeepSeek V4 Pro 0423 measured |
| MedCode (Vals AI) | 52.9% | 40.5% | Claude Sonnet 5.5 |
| SimpleQA Verified | 46.5% | 47.0% | DeepSeek V4 Pro 0423 |
| LMArena Text: science | 1483 | 1470 | Claude Sonnet 5.5 |
| LMArena Text: medicine and healthcare | 1464 | 1466 | DeepSeek V4 Pro 0423 |
| LMArena Text: legal and government | 1483 | 1464 | Claude Sonnet 5.5 |
| LMArena Text: business and finance | 1468 | 1443 | Claude Sonnet 5.5 |
| Neither model has a result on the other 7 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | Leader |
|---|---|---|---|
| Design Arena: websites | 1326 | 1234 | Claude Sonnet 5.5 |
| Design Arena: UI components | 1368 | 1219 | Claude Sonnet 5.5 |
| Design Arena: game dev | 1471 | 1228 | Claude Sonnet 5.5 |
| Design Arena: data viz | 1392 | 1203 | Claude Sonnet 5.5 |
| Design Arena: 3D | 1445 | 1253 | Claude Sonnet 5.5 |
| Design Arena: all code categories | 1364 | 1240 | Claude Sonnet 5.5 |
| Design Arena: SVG | Not measured | 1139 | Only DeepSeek V4 Pro 0423 measured |
| Design Arena: ASCII art | Not measured | 1149 | Only DeepSeek V4 Pro 0423 measured |
| LiveBench design | 85.0% | Not measured | Only Claude Sonnet 5.5 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index152
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | 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% | 62.9% | Claude Sonnet 5.5 |
| SAGE (Vals AI) | 51.8% | Not measured | Only Claude Sonnet 5.5 measured |
| MedScribe (Vals AI) | 91.1% | 75.1% | Claude Sonnet 5.5 |
| Long context reasoning (AA-LCR) | 82.7% | Not measured | Only Claude Sonnet 5.5 measured |
| DTBench | 97.3% | 90.7% | Claude Sonnet 5.5 |
| LMCA | 68.3% | 41.2% | Claude Sonnet 5.5 |
| Surface Evolver Bench | Not measured | 40.0% | Only DeepSeek V4 Pro 0423 measured |
| Furniture assembly | 75.0% | Not measured | Only Claude Sonnet 5.5 measured |
| CL-bench Life | Not measured | 13.5% | Only DeepSeek V4 Pro 0423 measured |
| LMArena Text | 1473 | 1451 | Claude Sonnet 5.5 |
| LMArena Text: instruction following | 1492 | 1445 | Claude Sonnet 5.5 |
| LMArena Text: creative writing | 1467 | 1446 | Claude Sonnet 5.5 |
| LMArena Vision | 1287 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: English | 1484 | 1459 | Claude Sonnet 5.5 |
| LMArena Text: non-English | 1456 | 1439 | Claude Sonnet 5.5 |
| LMArena Text: Chinese | 1535 | 1481 | Claude Sonnet 5.5 |
| LMArena Text: German | Not measured | 1458 | Only DeepSeek V4 Pro 0423 measured |
| LMArena Text: Japanese | Not measured | 1446 | Only DeepSeek V4 Pro 0423 measured |
| LMArena Text: Korean | Not measured | 1409 | Only DeepSeek V4 Pro 0423 measured |
| LMArena Text: French | 1499 | 1473 | Claude Sonnet 5.5 |
| LMArena Text: Spanish | 1451 | 1457 | DeepSeek V4 Pro 0423 |
| LMArena Text: Russian | 1454 | 1453 | Claude Sonnet 5.5 |
| LMArena Text: Polish | Not measured | 1461 | Only DeepSeek V4 Pro 0423 measured |
| LMArena Text: multi-turn | 1465 | 1468 | DeepSeek V4 Pro 0423 |
| LMArena Text: longer queries | 1495 | 1458 | Claude Sonnet 5.5 |
| LMArena Text: writing and language | 1474 | 1447 | Claude Sonnet 5.5 |
| LMArena Text: entertainment and media | 1461 | 1431 | 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 14 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4 Pro 0423 | 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
DeepSeek V4 Pro 0423 costs less
Repository review
50K input + 3K output tokens
DeepSeek V4 Pro 0423 costs less
Agent loop
200K input + 10K output tokens
DeepSeek V4 Pro 0423 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 | DeepSeek V4 Pro 0423 |
|---|---|---|
| Maker | Anthropic | DeepSeek |
| Weights | No public weights listed | Open weights |
| Released | September 28, 2026 | April 24, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $2.00 | $1.358 |
| Output $/Mtok | $10.00 | $2.976 |
| Coding index | 87.3 | 38.7 |
| Independent measurements behind it | 5 | 5 |
| Cost per solved task | Not computable | $0.57 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 5.5 better than DeepSeek V4 Pro 0423 for coding?
Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 38.7 for DeepSeek V4 Pro 0423. Pick DeepSeek V4 Pro 0423 for output tokens 3.4x cheaper ($2.976 vs $10.00 per million) and a larger context window (1.05M against 1M tokens).
Which is cheaper, Claude Sonnet 5.5 or DeepSeek V4 Pro 0423?
Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; DeepSeek V4 Pro 0423 costs $1.358 and $2.976. Cost per solved task is known for DeepSeek V4 Pro 0423 only.
Which has the bigger context window, Claude Sonnet 5.5 or DeepSeek V4 Pro 0423?
DeepSeek V4 Pro 0423, with 1.05M tokens against 1M.
How many benchmarks is the Claude Sonnet 5.5 vs DeepSeek V4 Pro 0423 comparison based on?
61 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 DeepSeek V4 Pro 0423's on 5. Where only one model has a result, the page says so instead of naming a winner.