Claude Opus 4.1 vs DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 leads Claude Opus 4.1 on the Artificial Analysis Intelligence Index, 34.3 to 22.8, and DeepSeek V4 Flash 0731 costs 267.9x less per output token ($0.28 vs $75.00 per million). Updated October 21, 2026; 26 benchmarks have a result for both.
Claude Opus 4.1 or DeepSeek V4 Flash 0731: which to pick
Only DeepSeek V4 Flash 0731 has a coding score, 51.8 on the Vibe Coding Index; Claude Opus 4.1 has none, so the two cannot be ranked on coding.
Pick Claude Opus 4.1 for work measured by MMLU Pro or LegalBench (Vals AI), where it leads.
- Shared results
- 26
- Claude Opus 4.1 only
- 47
- DeepSeek V4 Flash 0731 only
- 29
- 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 DeepSeek V4 Flash 0731 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 leads, 34.3 against 22.8.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only DeepSeek V4 Flash 0731 has a AA Agentic Index result, 41.0.
Directional only
Reasoning
GPQA Diamond
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 leads, 89.9% against 76.3%.
Same board, both measured
Math
AIME
No call
Only Claude Opus 4.1 has a AIME result, 78.2%.
Directional only
Knowledge
MMLU Pro
Claude Opus 4.1
Claude Opus 4.1 leads, 87.9% against 86.2%.
Same board, both measured
Web design
Design Arena: websites
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 leads, 1238 against 1177.
Same board, both measured
Long documents
Listed context window
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V4 Flash 0731
Claude Opus 4.1 $0.052, DeepSeek V4 Flash 0731 $0.0003 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only DeepSeek V4 Flash 0731 has the number, $0.01.
Directional only
At a glance
- Coding index
- Claude Opus 4.1 not benchmarked, DeepSeek V4 Flash 0731 51.8 from 4 benchmarks.
- Widest category
- Math, 30.8 points apart on average over 3 shared benchmarks.
- Widest single gap
- FrontierMath, tiers 1 to 3: Claude Opus 4.1 12.6% against DeepSeek V4 Flash 0731 57.5%, 44.9 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.1 $75.00 against DeepSeek V4 Flash 0731 $0.28 per million output tokens, 267.9x apart.
- Context window
- Claude Opus 4.1 takes 200K tokens, DeepSeek V4 Flash 0731 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 Opus 4.1 | Bars | DeepSeek V4 Flash 0731 | Ties |
|---|---|---|---|---|
| Coding | 0 | 2 | ||
| Intelligence | 0 | 2 | ||
| Reasoning | 0 | 4 | ||
| Math | 0 | 3 | ||
| Knowledge | 4 | 0 | ||
| Web design | 1 | 7 | ||
| General | 0 | 3 | ||
| All shared boards | 5 | 21 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index02
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| LMArena WebDev | 1390 | Not measured | Only Claude Opus 4.1 measured |
| AA Coding Index | Not measured | 69.1 | Only DeepSeek V4 Flash 0731 measured |
| LiveCodeBench (Vals AI) | 66.5% | 87.3% | DeepSeek V4 Flash 0731 |
| SWE-bench Verified (Vals AI) | Not measured | 88.8% | Only DeepSeek V4 Flash 0731 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 18.7% | Only DeepSeek V4 Flash 0731 measured |
| Vibe Code Bench (Vals AI) | Not measured | 74.7% | Only DeepSeek V4 Flash 0731 measured |
| Code migration (Vals AI) | Not measured | 38.6% | Only DeepSeek V4 Flash 0731 measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only DeepSeek V4 Flash 0731 measured |
| IOI (Vals AI) | Not measured | 32.7% | Only DeepSeek V4 Flash 0731 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 67.0% | Only DeepSeek V4 Flash 0731 measured |
| SkillsBench (Vals AI) | Not measured | 50.7% | Only DeepSeek V4 Flash 0731 measured |
| CyberBench (Vals AI) | Not measured | 72.1% | Only DeepSeek V4 Flash 0731 measured |
| SciCode | Not measured | 50.3% | Only DeepSeek V4 Flash 0731 measured |
| Terminal-Bench | 38.0% | Not measured | Only Claude Opus 4.1 measured |
| FrontierCode | Not measured | 18.8% | Only DeepSeek V4 Flash 0731 measured |
| WeirdML | 45.9% | 63.0% | DeepSeek V4 Flash 0731 |
| Cybench | 42.0% | Not measured | Only Claude Opus 4.1 measured |
| ALE-Bench | Not measured | 1306.1 | Only DeepSeek V4 Flash 0731 measured |
| LMArena Text: coding | 1479 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: software and IT | 1456 | Not measured | Only Claude Opus 4.1 measured |
| LMArena WebDev: HTML | 1399 | Not measured | Only Claude Opus 4.1 measured |
| SciCode | 4.6% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 17 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.8 | 34.3 | DeepSeek V4 Flash 0731 |
| Epoch Capabilities Index | 144.1 | 154.8 | DeepSeek V4 Flash 0731 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index10 boards, none shared
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 41.0 | Only DeepSeek V4 Flash 0731 measured |
| Finance Agent (Vals AI) | Not measured | 49.5% | Only DeepSeek V4 Flash 0731 measured |
| Tax Agent Bench (Vals AI) | Not measured | 28.1% | Only DeepSeek V4 Flash 0731 measured |
| Legal Research Bench (Vals AI) | Not measured | 30.3% | Only DeepSeek V4 Flash 0731 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 57.0% | Only DeepSeek V4 Flash 0731 measured |
| BioMysteryBench (Vals AI) | Not measured | 64.4% | Only DeepSeek V4 Flash 0731 measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 4.3% | Only DeepSeek V4 Flash 0731 measured |
| METR time horizons | 66.8% | Not measured | Only Claude Opus 4.1 measured |
| GDPval | 43.6% | Not measured | Only Claude Opus 4.1 measured |
| DeepResearch Bench | 48.3% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 31 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| GPQA Diamond | 76.3% | 89.9% | DeepSeek V4 Flash 0731 |
| MMMU Pro (Vals AI) | 77.5% | Not measured | Only Claude Opus 4.1 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 90.8% | Only DeepSeek V4 Flash 0731 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 38.6% | Only DeepSeek V4 Flash 0731 measured |
| GPQA Diamond (Epoch AI run) | 77.3% | 91.0% | DeepSeek V4 Flash 0731 |
| ARC-AGI | Not measured | 89.0% | Only DeepSeek V4 Flash 0731 measured |
| ARC-AGI-2 | Not measured | 61.4% | Only DeepSeek V4 Flash 0731 measured |
| SimpleBench | 60.0% | 61.1% | DeepSeek V4 Flash 0731 |
| Chess puzzles | Not measured | 32.0% | Only DeepSeek V4 Flash 0731 measured |
| Mystery game puzzles | 21.0% | 34.0% | DeepSeek V4 Flash 0731 |
| EBR-bench | 7.9% | Not measured | Only Claude Opus 4.1 measured |
| VPCT | 35.0% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: hard prompts | 1442 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: expert | 1438 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: hard prompts in English | 1451 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 7 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| AIME | 78.2% | Not measured | Only Claude Opus 4.1 measured |
| MATH 500 (Vals AI) | 95.4% | Not measured | Only Claude Opus 4.1 measured |
| MGSM (Vals AI) | 94.4% | Not measured | Only Claude Opus 4.1 measured |
| OTIS Mock AIME | 68.9% | 94.4% | DeepSeek V4 Flash 0731 |
| FrontierMath, tiers 1 to 3 | 12.6% | 57.5% | DeepSeek V4 Flash 0731 |
| FrontierMath, tier 4 | 2.4% | 24.4% | DeepSeek V4 Flash 0731 |
| ProofBench | Not measured | 56.0% | Only DeepSeek V4 Flash 0731 measured |
| LMArena Text: math | 1431 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: mathematical work | 1434 | Not measured | Only Claude Opus 4.1 measured |
| 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 Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| MMLU Pro | 87.9% | 86.2% | Claude Opus 4.1 |
| LegalBench (Vals AI) | 83.5% | 77.7% | Claude Opus 4.1 |
| CorpFin (Vals AI) | Not measured | 61.9% | Only DeepSeek V4 Flash 0731 measured |
| TaxEval (Vals AI) | 73.7% | 70.7% | Claude Opus 4.1 |
| MortgageTax (Vals AI) | 61.1% | Not measured | Only Claude Opus 4.1 measured |
| MedQA (Vals AI) | 93.6% | Not measured | Only Claude Opus 4.1 measured |
| MedCode (Vals AI) | 47.2% | 41.4% | Claude Opus 4.1 |
| SimpleQA Verified | Not measured | 33.6% | Only DeepSeek V4 Flash 0731 measured |
| LMArena Text: science | 1422 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: medicine and healthcare | 1416 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: legal and government | 1421 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: business and finance | 1406 | Not measured | Only Claude Opus 4.1 measured |
| FACTS Benchmark Suite | 40.4% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index17
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| Design Arena: websites | 1177 | 1238 | DeepSeek V4 Flash 0731 |
| Design Arena: UI components | 1165 | 1235 | DeepSeek V4 Flash 0731 |
| Design Arena: game dev | 1171 | 1208 | DeepSeek V4 Flash 0731 |
| Design Arena: data viz | 1166 | 1180 | DeepSeek V4 Flash 0731 |
| Design Arena: 3D | 1153 | 1209 | DeepSeek V4 Flash 0731 |
| Design Arena: all code categories | 1171 | 1230 | DeepSeek V4 Flash 0731 |
| Design Arena: SVG | 1152 | 1185 | DeepSeek V4 Flash 0731 |
| Design Arena: ASCII art | 1167 | 1090 | Claude Opus 4.1 |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 31.4% | Not measured | Only Claude Opus 4.1 measured |
| MedScribe (Vals AI) | 73.9% | 80.4% | DeepSeek V4 Flash 0731 |
| Long context reasoning (AA-LCR) | Not measured | 79.7% | Only DeepSeek V4 Flash 0731 measured |
| DTBench | 80.0% | 90.9% | DeepSeek V4 Flash 0731 |
| LMCA | 37.1% | 41.7% | DeepSeek V4 Flash 0731 |
| Creative writing (Lech Mazur) | 84.7% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text | 1419 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: instruction following | 1435 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: creative writing | 1412 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: English | 1433 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: non-English | 1405 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Chinese | 1427 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: German | 1413 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Japanese | 1377 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Korean | 1381 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: French | 1433 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Spanish | 1448 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Russian | 1422 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Polish | 1413 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: multi-turn | 1444 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: longer queries | 1455 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: writing and language | 1418 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: entertainment and media | 1398 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 23 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.1 | DeepSeek V4 Flash 0731 | 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 Flash 0731 costs less
Repository review
50K input + 3K output tokens
DeepSeek V4 Flash 0731 costs less
Agent loop
200K input + 10K output tokens
DeepSeek V4 Flash 0731 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 Opus 4.1 | DeepSeek V4 Flash 0731 |
|---|---|---|
| Maker | Anthropic | DeepSeek |
| Weights | No public weights listed | Open weights |
| Released | August 5, 2025 | July 31, 2026 |
| Context window | 200K | 1.05M |
| Input $/Mtok | $15.00 | $0.14 |
| Output $/Mtok | $75.00 | $0.28 |
| Coding index | Not benchmarked | 51.8 |
| Independent measurements behind it | 1 | 4 |
| Cost per solved task | Not computable | $0.01 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.1 better than DeepSeek V4 Flash 0731 for coding?
Only DeepSeek V4 Flash 0731 has a coding score, 51.8 on the Vibe Coding Index; Claude Opus 4.1 has none, so the two cannot be ranked on coding. Pick Claude Opus 4.1 for work measured by MMLU Pro or LegalBench (Vals AI), where it leads.
Which is cheaper, Claude Opus 4.1 or DeepSeek V4 Flash 0731?
Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; DeepSeek V4 Flash 0731 costs $0.14 and $0.28. Cost per solved task is known for DeepSeek V4 Flash 0731 only.
Which has the bigger context window, Claude Opus 4.1 or DeepSeek V4 Flash 0731?
DeepSeek V4 Flash 0731, with 1.05M tokens against 200K.
How many benchmarks is the Claude Opus 4.1 vs DeepSeek V4 Flash 0731 comparison based on?
26 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and DeepSeek V4 Flash 0731's on 4. Where only one model has a result, the page says so instead of naming a winner.