Claude Opus 4.1 vs DeepSeek V4.1 Flash
DeepSeek V4.1 Flash leads Claude Opus 4.1 on the Artificial Analysis Intelligence Index, 24.7 to 22.8, and DeepSeek V4.1 Flash costs 89.3x less per output token ($0.84 vs $75.00 per million). Updated October 22, 2026; 51 benchmarks have a result for both.
Claude Opus 4.1 or DeepSeek V4.1 Flash: which to pick
Only DeepSeek V4.1 Flash has a coding score, 62.5 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 LegalBench (Vals AI) or MedCode (Vals AI), where it leads.
- Shared results
- 51
- Claude Opus 4.1 only
- 22
- DeepSeek V4.1 Flash only
- 50
- 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 V4.1 Flash has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
DeepSeek V4.1 Flash
DeepSeek V4.1 Flash leads, 24.7 against 22.8.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Claude Opus 4.1 has a GPQA Diamond result, 76.3%.
Directional only
Math
AIME
No call
Only Claude Opus 4.1 has a AIME result, 78.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Opus 4.1 has a MMLU Pro result, 87.9%.
Directional only
Web design
Design Arena: websites
DeepSeek V4.1 Flash
DeepSeek V4.1 Flash leads, 1308 against 1176.
Same board, both measured
Long documents
Listed context window
DeepSeek V4.1 Flash
DeepSeek V4.1 Flash takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V4.1 Flash
Claude Opus 4.1 $0.052, DeepSeek V4.1 Flash $0.0006 per turn.
List prices
At a glance
- Coding index
- Claude Opus 4.1 not benchmarked, DeepSeek V4.1 Flash 62.5 from 5 benchmarks.
- Widest category
- Math, 25.0 points apart on average over 5 shared benchmarks.
- Widest single gap
- FrontierMath, tiers 1 to 3: Claude Opus 4.1 12.6% against DeepSeek V4.1 Flash 67.4%, 54.7 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.1 $75.00 against DeepSeek V4.1 Flash $0.84 per million output tokens, 89.3x apart.
- Context window
- Claude Opus 4.1 takes 200K tokens, DeepSeek V4.1 Flash 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 V4.1 Flash | Ties |
|---|---|---|---|---|
| Coding | 0 | 4 | ||
| Intelligence | 0 | 2 | ||
| Reasoning | 0 | 5 | ||
| Math | 0 | 5 | ||
| Knowledge | 2 | 4 | ||
| Web design | 0 | 8 | ||
| General | 0 | 21 | ||
| All shared boards | 2 | 49 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index04
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 90.2% | Only DeepSeek V4.1 Flash measured |
| LMArena WebDev | 1390 | 1618 | DeepSeek V4.1 Flash |
| LiveCodeBench (Vals AI) | 66.5% | Not measured | Only Claude Opus 4.1 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 19.7% | Only DeepSeek V4.1 Flash measured |
| Vibe Code Bench (Vals AI) | Not measured | 84.7% | Only DeepSeek V4.1 Flash measured |
| Code migration (Vals AI) | Not measured | 45.6% | Only DeepSeek V4.1 Flash measured |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only DeepSeek V4.1 Flash measured |
| IOI (Vals AI) | Not measured | 40.3% | Only DeepSeek V4.1 Flash measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 74.5% | Only DeepSeek V4.1 Flash measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 46.5% | Only DeepSeek V4.1 Flash measured |
| Vibe Code Bench 1-100 (Vals AI) | Not measured | 16.4% | Only DeepSeek V4.1 Flash measured |
| SkillsBench (Vals AI) | Not measured | 69.8% | Only DeepSeek V4.1 Flash measured |
| CyberBench (Vals AI) | Not measured | 73.7% | Only DeepSeek V4.1 Flash measured |
| SciCode | Not measured | 51.9% | Only DeepSeek V4.1 Flash measured |
| Terminal-Bench | 38.0% | Not measured | Only Claude Opus 4.1 measured |
| FrontierCode | Not measured | 43.9% | Only DeepSeek V4.1 Flash measured |
| WeirdML | 45.9% | Not measured | Only Claude Opus 4.1 measured |
| Cybench | 42.0% | Not measured | Only Claude Opus 4.1 measured |
| ALE-Bench | Not measured | 1092.3 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: coding | 1479 | 1502 | DeepSeek V4.1 Flash |
| LMArena Text: software and IT | 1456 | 1496 | DeepSeek V4.1 Flash |
| LMArena WebDev: React | Not measured | 1628 | Only DeepSeek V4.1 Flash measured |
| LMArena WebDev: HTML | 1399 | 1612 | DeepSeek V4.1 Flash |
| LMArena WebDev: from an image | Not measured | 1606 | Only DeepSeek V4.1 Flash measured |
| SciCode | 4.6% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 14 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.8 | 24.7 | DeepSeek V4.1 Flash |
| Epoch Capabilities Index | 144.1 | 155.9 | DeepSeek V4.1 Flash |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index15 boards, none shared
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| LiveBench research | Not measured | 86.8% | Only DeepSeek V4.1 Flash measured |
| LiveBench browser | Not measured | 84.0% | Only DeepSeek V4.1 Flash measured |
| LiveBench long agentic | Not measured | 40.1% | Only DeepSeek V4.1 Flash measured |
| SREBench (Vals AI) | Not measured | 0.8% | Only DeepSeek V4.1 Flash measured |
| Finance Agent (Vals AI) | Not measured | 53.5% | Only DeepSeek V4.1 Flash measured |
| Tax Agent Bench (Vals AI) | Not measured | 26.6% | Only DeepSeek V4.1 Flash measured |
| Legal Research Bench (Vals AI) | Not measured | 41.4% | Only DeepSeek V4.1 Flash measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 57.2% | Only DeepSeek V4.1 Flash measured |
| BioMysteryBench (Vals AI) | Not measured | 67.8% | Only DeepSeek V4.1 Flash measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 0.0% | Only DeepSeek V4.1 Flash measured |
| Vals Science Index | Not measured | 29.6% | Only DeepSeek V4.1 Flash measured |
| APEX-Agents | Not measured | 39.5% | Only DeepSeek V4.1 Flash 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 26 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| GPQA Diamond | 76.3% | Not measured | Only Claude Opus 4.1 measured |
| LiveBench reasoning | Not measured | 86.7% | Only DeepSeek V4.1 Flash measured |
| MysteryMechanism (Vals AI) | Not measured | 21.2% | Only DeepSeek V4.1 Flash measured |
| MMMU Pro (Vals AI) | 77.5% | Not measured | Only Claude Opus 4.1 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 39.2% | Only DeepSeek V4.1 Flash measured |
| GPQA Diamond (Epoch AI run) | 77.3% | 89.8% | DeepSeek V4.1 Flash |
| ARC-AGI | Not measured | 94.5% | Only DeepSeek V4.1 Flash measured |
| ARC-AGI-2 | Not measured | 72.9% | Only DeepSeek V4.1 Flash measured |
| SimpleBench | 60.0% | Not measured | Only Claude Opus 4.1 measured |
| Chess puzzles | Not measured | 48.0% | Only DeepSeek V4.1 Flash measured |
| Mystery game puzzles | 21.0% | 43.0% | DeepSeek V4.1 Flash |
| 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 | 1483 | DeepSeek V4.1 Flash |
| LMArena Text: expert | 1438 | 1501 | DeepSeek V4.1 Flash |
| LMArena Text: hard prompts in English | 1451 | 1488 | DeepSeek V4.1 Flash |
| LMArena Vision: diagrams | Not measured | 1297 | Only DeepSeek V4.1 Flash measured |
| LMArena Vision: homework | Not measured | 1307 | Only DeepSeek V4.1 Flash measured |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | 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% | 98.3% | DeepSeek V4.1 Flash |
| FrontierMath, tiers 1 to 3 | 12.6% | 67.4% | DeepSeek V4.1 Flash |
| FrontierMath, tier 4 | 2.4% | 26.8% | DeepSeek V4.1 Flash |
| ProofBench | Not measured | 54.0% | Only DeepSeek V4.1 Flash measured |
| LMArena Text: math | 1431 | 1478 | DeepSeek V4.1 Flash |
| LMArena Text: mathematical work | 1434 | 1485 | DeepSeek V4.1 Flash |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index24
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| MMLU Pro | 87.9% | Not measured | Only Claude Opus 4.1 measured |
| LegalBench (Vals AI) | 83.5% | 83.3% | Claude Opus 4.1 |
| TaxEval (Vals AI) | 73.7% | Not measured | Only Claude Opus 4.1 measured |
| 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% | 41.2% | Claude Opus 4.1 |
| SimpleQA Verified | Not measured | 42.9% | Only DeepSeek V4.1 Flash measured |
| LMArena Text: science | 1422 | 1469 | DeepSeek V4.1 Flash |
| LMArena Text: medicine and healthcare | 1416 | 1484 | DeepSeek V4.1 Flash |
| LMArena Text: legal and government | 1421 | 1443 | DeepSeek V4.1 Flash |
| LMArena Text: business and finance | 1406 | 1461 | DeepSeek V4.1 Flash |
| FACTS Benchmark Suite | 40.4% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 6 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index08
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| Design Arena: websites | 1176 | 1308 | DeepSeek V4.1 Flash |
| Design Arena: UI components | 1162 | 1312 | DeepSeek V4.1 Flash |
| Design Arena: game dev | 1171 | 1330 | DeepSeek V4.1 Flash |
| Design Arena: data viz | 1166 | 1291 | DeepSeek V4.1 Flash |
| Design Arena: 3D | 1152 | 1355 | DeepSeek V4.1 Flash |
| Design Arena: all code categories | 1170 | 1320 | DeepSeek V4.1 Flash |
| Design Arena: SVG | 1152 | 1245 | DeepSeek V4.1 Flash |
| Design Arena: ASCII art | 1167 | 1265 | DeepSeek V4.1 Flash |
| LiveBench design | Not measured | 79.2% | Only DeepSeek V4.1 Flash measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index021
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| LiveBench data analysis | Not measured | 79.3% | Only DeepSeek V4.1 Flash measured |
| Public Benefits Bench (Vals AI) | Not measured | 64.3% | Only DeepSeek V4.1 Flash measured |
| SAGE (Vals AI) | 31.4% | 47.9% | DeepSeek V4.1 Flash |
| MedScribe (Vals AI) | 73.9% | 85.5% | DeepSeek V4.1 Flash |
| Long context reasoning (AA-LCR) | Not measured | 84.0% | Only DeepSeek V4.1 Flash measured |
| DTBench | 80.0% | 89.9% | DeepSeek V4.1 Flash |
| LMCA | 37.1% | 47.0% | DeepSeek V4.1 Flash |
| Creative writing (Lech Mazur) | 84.7% | Not measured | Only Claude Opus 4.1 measured |
| Surface Evolver Bench | Not measured | 46.3% | Only DeepSeek V4.1 Flash measured |
| Furniture assembly | Not measured | 34.2% | Only DeepSeek V4.1 Flash measured |
| LMArena Text | 1419 | 1464 | DeepSeek V4.1 Flash |
| LMArena Text: instruction following | 1435 | 1473 | DeepSeek V4.1 Flash |
| LMArena Text: creative writing | 1412 | 1437 | DeepSeek V4.1 Flash |
| LMArena Vision | Not measured | 1278 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: English | 1433 | 1473 | DeepSeek V4.1 Flash |
| LMArena Text: non-English | 1405 | 1449 | DeepSeek V4.1 Flash |
| LMArena Text: Chinese | 1427 | 1501 | DeepSeek V4.1 Flash |
| LMArena Text: German | 1413 | 1470 | DeepSeek V4.1 Flash |
| LMArena Text: Japanese | 1377 | 1432 | DeepSeek V4.1 Flash |
| LMArena Text: Korean | 1381 | 1436 | DeepSeek V4.1 Flash |
| LMArena Text: French | 1433 | 1465 | DeepSeek V4.1 Flash |
| LMArena Text: Spanish | 1448 | 1459 | DeepSeek V4.1 Flash |
| LMArena Text: Russian | 1422 | 1467 | DeepSeek V4.1 Flash |
| LMArena Text: Polish | 1413 | 1457 | DeepSeek V4.1 Flash |
| LMArena Text: multi-turn | 1444 | 1461 | DeepSeek V4.1 Flash |
| LMArena Text: longer queries | 1455 | 1473 | DeepSeek V4.1 Flash |
| LMArena Text: writing and language | 1418 | 1450 | DeepSeek V4.1 Flash |
| LMArena Text: entertainment and media | 1398 | 1445 | DeepSeek V4.1 Flash |
| LMArena Vision: English | Not measured | 1288 | Only DeepSeek V4.1 Flash measured |
| LMArena Vision: Chinese | Not measured | 1327 | Only DeepSeek V4.1 Flash measured |
| LMArena Vision: reading text | Not measured | 1282 | Only DeepSeek V4.1 Flash measured |
| LMArena Vision: humor | Not measured | 1260 | Only DeepSeek V4.1 Flash measured |
| LMArena Vision: creative writing | Not measured | 1275 | Only DeepSeek V4.1 Flash measured |
| Neither model has a result on the other 13 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.1 | DeepSeek V4.1 Flash | 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 V4.1 Flash costs less
Repository review
50K input + 3K output tokens
DeepSeek V4.1 Flash costs less
Agent loop
200K input + 10K output tokens
DeepSeek V4.1 Flash 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 V4.1 Flash |
|---|---|---|
| Maker | Anthropic | DeepSeek |
| Weights | No public weights listed | Open weights |
| Released | August 5, 2025 | September 10, 2026 |
| Context window | 200K | 1.05M |
| Input $/Mtok | $15.00 | $0.2225 |
| Output $/Mtok | $75.00 | $0.84 |
| Coding index | Not benchmarked | 62.5 |
| Independent measurements behind it | 1 | 5 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.1 better than DeepSeek V4.1 Flash for coding?
Only DeepSeek V4.1 Flash has a coding score, 62.5 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 LegalBench (Vals AI) or MedCode (Vals AI), where it leads.
Which is cheaper, Claude Opus 4.1 or DeepSeek V4.1 Flash?
Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; DeepSeek V4.1 Flash costs $0.2225 and $0.84. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Opus 4.1 or DeepSeek V4.1 Flash?
DeepSeek V4.1 Flash, with 1.05M tokens against 200K.
How many benchmarks is the Claude Opus 4.1 vs DeepSeek V4.1 Flash comparison based on?
51 benchmarks have a result for both models as of October 22, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and DeepSeek V4.1 Flash's on 5. Where only one model has a result, the page says so instead of naming a winner.