Claude Opus 4.5 vs DeepSeek V4 Flash 0423
Claude Opus 4.5 leads DeepSeek V4 Flash 0423 on the Artificial Analysis Intelligence Index, 29.1 to 24.4, and DeepSeek V4 Flash 0423 costs 89.3x less per output token ($0.28 vs $25.00 per million). Updated October 22, 2026; 46 benchmarks have a result for both.
Claude Opus 4.5 or DeepSeek V4 Flash 0423: which to pick
Only Claude Opus 4.5 has a coding score, 44.0 on the Vibe Coding Index; DeepSeek V4 Flash 0423 has none, so the two cannot be ranked on coding.
Pick DeepSeek V4 Flash 0423 for output tokens 89.3x cheaper ($0.28 vs $25.00 per million) and a larger context window (1.05M against 200K tokens).
- Shared results
- 46
- Claude Opus 4.5 only
- 62
- DeepSeek V4 Flash 0423 only
- 3
- 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 Opus 4.5 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Claude Opus 4.5
Claude Opus 4.5 leads, 29.1 against 24.4.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only DeepSeek V4 Flash 0423 has a AA Agentic Index result, 26.3.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Opus 4.5 has a GPQA Diamond result, 85.9%.
Directional only
Math
AIME
No call
Only Claude Opus 4.5 has a AIME result, 95.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Opus 4.5 has a MMLU Pro result, 87.3%.
Directional only
Web design
Design Arena: websites
Claude Opus 4.5
Claude Opus 4.5 leads, 1247 against 1207.
Same board, both measured
Long documents
Listed context window
DeepSeek V4 Flash 0423
DeepSeek V4 Flash 0423 takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V4 Flash 0423
Claude Opus 4.5 $0.018, DeepSeek V4 Flash 0423 $0.0003 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Opus 4.5 has the number, $1.37.
Directional only
At a glance
- Coding index
- Claude Opus 4.5 44.0 from 3 benchmarks, DeepSeek V4 Flash 0423 not benchmarked.
- Widest category
- Reasoning, 12.4 points apart on average over 5 shared benchmarks.
- Widest single gap
- Kagi LLM Benchmark: Claude Opus 4.5 80.2% against DeepSeek V4 Flash 0423 52.2%, 28.0 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.5 $25.00 against DeepSeek V4 Flash 0423 $0.28 per million output tokens, 89.3x apart.
- Context window
- Claude Opus 4.5 takes 200K tokens, DeepSeek V4 Flash 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 Opus 4.5 | Bars | DeepSeek V4 Flash 0423 | Ties |
|---|---|---|---|---|
| Coding | 3 | 3 | ||
| Intelligence | 2 | 0 | ||
| Reasoning | 5 | 0 | ||
| Math | 2 | 0 | ||
| Knowledge | 3 | 1 | ||
| Web design | 8 | 0 | ||
| General | 19 | 0 | ||
| All shared boards | 42 | 4 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index33
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| SWE-bench Verified | 79.2% | Not measured | Only Claude Opus 4.5 measured |
| SWE-bench (full test set) | 52.6% | Not measured | Only Claude Opus 4.5 measured |
| SWE-bench Multilingual | 70.7% | Not measured | Only Claude Opus 4.5 measured |
| LMArena WebDev | 1494 | 1582 | DeepSeek V4 Flash 0423 |
| AA Coding Index | Not measured | 52.0 | Only DeepSeek V4 Flash 0423 measured |
| LiveCodeBench (Vals AI) | 83.7% | Not measured | Only Claude Opus 4.5 measured |
| SWE-bench Verified (Vals AI) | 76.4% | Not measured | Only Claude Opus 4.5 measured |
| Vibe Code Bench (Vals AI) | 20.6% | Not measured | Only Claude Opus 4.5 measured |
| LiveCodeBench (Artificial Analysis run) | 87.1% | Not measured | Only Claude Opus 4.5 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 47.0% | Not measured | Only Claude Opus 4.5 measured |
| Terminal-Bench | 63.1% | Not measured | Only Claude Opus 4.5 measured |
| GSO-Bench | 26.5% | Not measured | Only Claude Opus 4.5 measured |
| WeirdML | 63.7% | 45.6% | Claude Opus 4.5 |
| Cybench | 82.0% | Not measured | Only Claude Opus 4.5 measured |
| ALE-Bench | Not measured | 678.2 | Only DeepSeek V4 Flash 0423 measured |
| LMArena Text: coding | 1503 | 1457 | Claude Opus 4.5 |
| LMArena Text: software and IT | 1483 | 1453 | Claude Opus 4.5 |
| LMArena WebDev: React | 1478 | 1585 | DeepSeek V4 Flash 0423 |
| LMArena WebDev: HTML | 1510 | 1558 | DeepSeek V4 Flash 0423 |
| Neither model has a result on the other 20 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| AA Intelligence Index | 29.1 | 24.4 | Claude Opus 4.5 |
| Epoch Capabilities Index | 150.1 | 146.1 | Claude Opus 4.5 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index14 boards, none shared
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 26.3 | Only DeepSeek V4 Flash 0423 measured |
| Design Arena: agents building web apps | 1159 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: agents building full-stack apps | 1156 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: agents building mobile apps | 1189 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: agents building Android apps | 1176 | Not measured | Only Claude Opus 4.5 measured |
| τ²-Bench Telecom | 89.5% | Not measured | Only Claude Opus 4.5 measured |
| METR time horizons | 75.0% | Not measured | Only Claude Opus 4.5 measured |
| Remote Labor Index | 3.8% | Not measured | Only Claude Opus 4.5 measured |
| GDPval | 45.5% | Not measured | Only Claude Opus 4.5 measured |
| BALROG | 43.5% | Not measured | Only Claude Opus 4.5 measured |
| DeepResearch Bench | 54.8% | Not measured | Only Claude Opus 4.5 measured |
| OSWorld | 66.3% | Not measured | Only Claude Opus 4.5 measured |
| Vending-Bench 2 | $4,967 | Not measured | Only Claude Opus 4.5 measured |
| Berkeley Function Calling Leaderboard (BFCL) | 77.5% | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 27 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| GPQA Diamond | 85.9% | Not measured | Only Claude Opus 4.5 measured |
| MMMU Pro (Vals AI) | 83.0% | Not measured | Only Claude Opus 4.5 measured |
| GPQA Diamond (Artificial Analysis run) | 86.6% | Not measured | Only Claude Opus 4.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 30.1% | Not measured | Only Claude Opus 4.5 measured |
| GPQA Diamond (Epoch AI run) | 86.0% | Not measured | Only Claude Opus 4.5 measured |
| ARC-AGI | 80.0% | Not measured | Only Claude Opus 4.5 measured |
| ARC-AGI-2 | 37.6% | Not measured | Only Claude Opus 4.5 measured |
| SimpleBench | 62.0% | 46.3% | Claude Opus 4.5 |
| Chess puzzles | 14.0% | Not measured | Only Claude Opus 4.5 measured |
| Mystery game puzzles | 22.0% | Not measured | Only Claude Opus 4.5 measured |
| EBR-bench | 14.3% | Not measured | Only Claude Opus 4.5 measured |
| VPCT | 40.0% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: hard prompts | 1476 | 1444 | Claude Opus 4.5 |
| LMArena Text: expert | 1487 | 1441 | Claude Opus 4.5 |
| LMArena Text: hard prompts in English | 1482 | 1449 | Claude Opus 4.5 |
| Kagi LLM Benchmark | 80.2% | 52.2% | Claude Opus 4.5 |
| Neither model has a result on the other 6 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| AIME | 95.4% | Not measured | Only Claude Opus 4.5 measured |
| MGSM (Vals AI) | 95.2% | Not measured | Only Claude Opus 4.5 measured |
| AA Math Index | 91.3 | Not measured | Only Claude Opus 4.5 measured |
| AIME 2025 (Artificial Analysis run) | 91.3% | Not measured | Only Claude Opus 4.5 measured |
| OTIS Mock AIME | 86.1% | Not measured | Only Claude Opus 4.5 measured |
| FrontierMath, tiers 1 to 3 | 34.4% | Not measured | Only Claude Opus 4.5 measured |
| FrontierMath, tier 4 | 4.9% | Not measured | Only Claude Opus 4.5 measured |
| ProofBench | 36.0% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: math | 1463 | 1426 | Claude Opus 4.5 |
| LMArena Text: mathematical work | 1468 | 1432 | Claude Opus 4.5 |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index31
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| MMLU Pro | 87.3% | Not measured | Only Claude Opus 4.5 measured |
| LegalBench (Vals AI) | 84.6% | Not measured | Only Claude Opus 4.5 measured |
| CaseLaw (Vals AI) | 62.6% | Not measured | Only Claude Opus 4.5 measured |
| CorpFin (Vals AI) | 65.1% | Not measured | Only Claude Opus 4.5 measured |
| TaxEval (Vals AI) | 74.9% | Not measured | Only Claude Opus 4.5 measured |
| MortgageTax (Vals AI) | 68.7% | Not measured | Only Claude Opus 4.5 measured |
| MedQA (Vals AI) | 95.9% | Not measured | Only Claude Opus 4.5 measured |
| MedCode (Vals AI) | 49.2% | Not measured | Only Claude Opus 4.5 measured |
| MMLU Pro (Artificial Analysis run) | 89.5% | Not measured | Only Claude Opus 4.5 measured |
| SimpleQA Verified | 45.7% | Not measured | Only Claude Opus 4.5 measured |
| GeoBench | 75.0% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: science | 1454 | 1446 | Claude Opus 4.5 |
| LMArena Text: medicine and healthcare | 1444 | 1448 | DeepSeek V4 Flash 0423 |
| LMArena Text: legal and government | 1459 | 1439 | Claude Opus 4.5 |
| LMArena Text: business and finance | 1448 | 1425 | Claude Opus 4.5 |
| FACTS Benchmark Suite | 43.9% | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 2 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index80
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| Design Arena: websites | 1247 | 1207 | Claude Opus 4.5 |
| Design Arena: UI components | 1235 | 1162 | Claude Opus 4.5 |
| Design Arena: game dev | 1228 | 1196 | Claude Opus 4.5 |
| Design Arena: data viz | 1243 | 1127 | Claude Opus 4.5 |
| Design Arena: 3D | 1213 | 1188 | Claude Opus 4.5 |
| Design Arena: all code categories | 1242 | 1205 | Claude Opus 4.5 |
| Design Arena: SVG | 1180 | 1155 | Claude Opus 4.5 |
| Design Arena: ASCII art | 1190 | 1109 | Claude Opus 4.5 |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index190
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 0423 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 52.1% | Not measured | Only Claude Opus 4.5 measured |
| MedScribe (Vals AI) | 85.3% | Not measured | Only Claude Opus 4.5 measured |
| IFBench | 58.0% | Not measured | Only Claude Opus 4.5 measured |
| Long context reasoning (AA-LCR) | 77.3% | Not measured | Only Claude Opus 4.5 measured |
| DTBench | 89.9% | 86.4% | Claude Opus 4.5 |
| LMCA | 44.5% | 35.9% | Claude Opus 4.5 |
| CL-bench | 21.1% | Not measured | Only Claude Opus 4.5 measured |
| Furniture assembly | 28.3% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text | 1451 | 1432 | Claude Opus 4.5 |
| LMArena Text: instruction following | 1478 | 1421 | Claude Opus 4.5 |
| LMArena Text: creative writing | 1445 | 1403 | Claude Opus 4.5 |
| LMArena Text: English | 1461 | 1441 | Claude Opus 4.5 |
| LMArena Text: non-English | 1438 | 1419 | Claude Opus 4.5 |
| LMArena Text: Chinese | 1470 | 1463 | Claude Opus 4.5 |
| LMArena Text: German | 1449 | 1419 | Claude Opus 4.5 |
| LMArena Text: Japanese | 1417 | 1389 | Claude Opus 4.5 |
| LMArena Text: Korean | 1424 | 1383 | Claude Opus 4.5 |
| LMArena Text: French | 1471 | 1439 | Claude Opus 4.5 |
| LMArena Text: Spanish | 1457 | 1436 | Claude Opus 4.5 |
| LMArena Text: Russian | 1447 | 1427 | Claude Opus 4.5 |
| LMArena Text: Polish | 1439 | 1436 | Claude Opus 4.5 |
| LMArena Text: multi-turn | 1466 | 1449 | Claude Opus 4.5 |
| LMArena Text: longer queries | 1479 | 1434 | Claude Opus 4.5 |
| LMArena Text: writing and language | 1452 | 1410 | Claude Opus 4.5 |
| LMArena Text: entertainment and media | 1434 | 1400 | Claude Opus 4.5 |
| LMArena Document | 1462 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 20 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.5 | DeepSeek V4 Flash 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 Flash 0423 costs less
Repository review
50K input + 3K output tokens
DeepSeek V4 Flash 0423 costs less
Agent loop
200K input + 10K output tokens
DeepSeek V4 Flash 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 Opus 4.5 | DeepSeek V4 Flash 0423 |
|---|---|---|
| Maker | Anthropic | DeepSeek |
| Weights | No public weights listed | Open weights |
| Released | November 24, 2025 | April 24, 2026 |
| Context window | 200K | 1.05M |
| Input $/Mtok | $5.00 | $0.14 |
| Output $/Mtok | $25.00 | $0.28 |
| Coding index | 44.0 | Not benchmarked |
| Independent measurements behind it | 3 | 1 |
| Cost per solved task | $1.37 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.5 better than DeepSeek V4 Flash 0423 for coding?
Only Claude Opus 4.5 has a coding score, 44.0 on the Vibe Coding Index; DeepSeek V4 Flash 0423 has none, so the two cannot be ranked on coding. Pick DeepSeek V4 Flash 0423 for output tokens 89.3x cheaper ($0.28 vs $25.00 per million) and a larger context window (1.05M against 200K tokens).
Which is cheaper, Claude Opus 4.5 or DeepSeek V4 Flash 0423?
Claude Opus 4.5 costs $5.00 per million input tokens and $25.00 per million output tokens; DeepSeek V4 Flash 0423 costs $0.14 and $0.28. Cost per solved task is known for Claude Opus 4.5 only.
Which has the bigger context window, Claude Opus 4.5 or DeepSeek V4 Flash 0423?
DeepSeek V4 Flash 0423, with 1.05M tokens against 200K.
How many benchmarks is the Claude Opus 4.5 vs DeepSeek V4 Flash 0423 comparison based on?
46 benchmarks have a result for both models as of October 22, 2026. Claude Opus 4.5's coding index rests on 3 independent benchmarks and DeepSeek V4 Flash 0423's on 1. Where only one model has a result, the page says so instead of naming a winner.