Claude Haiku 5.5 vs DeepSeek V4.1 Flash
Updated October 21, 2026. 57 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Claude Haiku 5.5 and DeepSeek V4.1 Flash are level for coding, 75.9 against 77.2 on the Vibe Coding Index, so price and context decide.
Pick Claude Haiku 5.5 when output tokens cost 1.1x less, or when what matters is LiveBench coding or Terminal-Bench 4 (Vals AI), where it leads. Pick DeepSeek V4.1 Flash when the context window is larger, 1.05M against 1M tokens, or when what matters is LMArena WebDev or Code migration (Vals AI), where it leads.
- Shared results
- 57
- Claude Haiku 5.5 only
- 5
- DeepSeek V4.1 Flash only
- 44
- Like-for-like categories
- 8 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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, four public coding benchmarks
No call
Level: 75.9 against 77.2, inside 2 points.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Haiku 5.5
Claude Haiku 5.5 leads, 43.4 against 24.7.
Same board, both measured
Web design
Design Arena: websites
DeepSeek V4.1 Flash
DeepSeek V4.1 Flash leads, 1309 against 1263.
Same board, both measured
General
Vals Index
No call
Only Claude Haiku 5.5 has a Vals Index result, 58.7%.
Directional only
Long documents
Listed context window
DeepSeek V4.1 Flash
DeepSeek V4.1 Flash takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V4.1 Flash
Claude Haiku 5.5 $0.0003, DeepSeek V4.1 Flash $0.0003 per turn.
List prices
At a glance
- Coding index
- Claude Haiku 5.5 75.9 from 2 benchmarks, DeepSeek V4.1 Flash 77.2 from 2 benchmarks.
- Widest category
- Math, 15.7 points apart on average over 4 shared benchmarks.
- Widest single gap
- ProofBench: Claude Haiku 5.5 89.0% against DeepSeek V4.1 Flash 54.0%, 35.0 points apart on a 0 to 100 scale.
- Output price
- Claude Haiku 5.5 $0.50 against DeepSeek V4.1 Flash $0.525 per million output tokens, 1.1x apart.
- Context window
- Claude Haiku 5.5 takes 1M 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 Haiku 5.5 | Bars | DeepSeek V4.1 Flash | Ties |
|---|---|---|---|---|
| Coding | 9 | 5 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 10 | 2 | ||
| Reasoning | 3 | 5 | ||
| Math | 4 | 0 | ||
| Knowledge | 1 | 1 | ||
| Web design | 2 | 5 | ||
| General | 4 | 4 | ||
| All shared boards | 35 | 22 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index95
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| LiveBench coding | 91.4% | 90.2% | Claude Haiku 5.5 |
| LMArena WebDev | 1586 | 1618 | DeepSeek V4.1 Flash |
| Terminal-Bench 4 (Vals AI) | 36.4% | 19.7% | Claude Haiku 5.5 |
| Vibe Code Bench (Vals AI) | 90.4% | 84.7% | Claude Haiku 5.5 |
| Code migration (Vals AI) | 44.6% | 45.6% | DeepSeek V4.1 Flash |
| ProgramBench (Vals AI) | 2.5% | 0.5% | Claude Haiku 5.5 |
| IOI (Vals AI) | 47.3% | 40.3% | Claude Haiku 5.5 |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 74.5% | Only DeepSeek V4.1 Flash measured |
| SWE-bench Multimodal (Vals AI) | 44.0% | 46.5% | DeepSeek V4.1 Flash |
| Vibe Code Bench 1-100 (Vals AI) | 20.4% | 16.4% | Claude Haiku 5.5 |
| SkillsBench (Vals AI) | Not measured | 69.8% | Only DeepSeek V4.1 Flash measured |
| CyberBench (Vals AI) | 75.5% | 73.7% | Claude Haiku 5.5 |
| SciCode | 55.0% | 51.9% | Claude Haiku 5.5 |
| FrontierCode | 46.4% | 43.9% | Claude Haiku 5.5 |
| FrontierSWE | 43.8% | Not measured | Only Claude Haiku 5.5 measured |
| ALE-Bench | Not measured | 1092.3 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: coding | Not measured | 1502 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: software and IT | Not measured | 1496 | Only DeepSeek V4.1 Flash measured |
| LMArena WebDev: React | 1605 | 1628 | DeepSeek V4.1 Flash |
| LMArena WebDev: HTML | 1569 | 1612 | DeepSeek V4.1 Flash |
| LMArena WebDev: from an image | Not measured | 1606 | Only DeepSeek V4.1 Flash measured |
| Neither model has a result on the other 17 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| AA Intelligence Index | 43.4 | 24.7 | Claude Haiku 5.5 |
| Epoch Capabilities Index | 159.3 | 155.9 | Claude Haiku 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index102
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| LiveBench research | 81.9% | 86.8% | DeepSeek V4.1 Flash |
| LiveBench browser | 80.0% | 84.0% | DeepSeek V4.1 Flash |
| LiveBench long agentic | 57.6% | 40.1% | Claude Haiku 5.5 |
| SREBench (Vals AI) | 5.7% | 0.8% | Claude Haiku 5.5 |
| Finance Agent (Vals AI) | 54.1% | 53.5% | Claude Haiku 5.5 |
| Tax Agent Bench (Vals AI) | 31.9% | 26.6% | Claude Haiku 5.5 |
| Legal Research Bench (Vals AI) | 43.3% | 41.4% | Claude Haiku 5.5 |
| Harvey's Legal Agent Benchmark (Vals AI) | 4.2% | Not measured | Only Claude Haiku 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 59.0% | 57.2% | Claude Haiku 5.5 |
| BioMysteryBench (Vals AI) | 70.4% | 67.8% | Claude Haiku 5.5 |
| Terminal-Bench-Science (Vals AI) | 10.0% | 0.0% | Claude Haiku 5.5 |
| Vals Science Index | 38.5% | 29.6% | Claude Haiku 5.5 |
| APEX-Agents | 56.1% | 39.5% | Claude Haiku 5.5 |
| Vending-Bench 2 | $3,602 | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 25 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index35
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| LiveBench reasoning | 82.4% | 86.7% | DeepSeek V4.1 Flash |
| MysteryMechanism (Vals AI) | 35.1% | 21.2% | Claude Haiku 5.5 |
| Humanity's Last Exam (Artificial Analysis run) | 44.4% | 39.2% | Claude Haiku 5.5 |
| GPQA Diamond (Epoch AI run) | 89.6% | 89.8% | DeepSeek V4.1 Flash |
| ARC-AGI | 89.0% | 94.5% | DeepSeek V4.1 Flash |
| ARC-AGI-2 | 61.3% | 72.9% | DeepSeek V4.1 Flash |
| Chess puzzles | 55.0% | 48.0% | Claude Haiku 5.5 |
| Mystery game puzzles | 30.0% | 43.0% | DeepSeek V4.1 Flash |
| EBR-bench | 43.8% | Not measured | Only Claude Haiku 5.5 measured |
| LMArena Text: hard prompts | Not measured | 1483 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: expert | Not measured | 1501 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: hard prompts in English | Not measured | 1488 | Only DeepSeek V4.1 Flash measured |
| 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 7 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| OTIS Mock AIME | 98.9% | 98.3% | Claude Haiku 5.5 |
| FrontierMath, tiers 1 to 3 | 75.1% | 67.4% | Claude Haiku 5.5 |
| FrontierMath, tier 4 | 46.3% | 26.8% | Claude Haiku 5.5 |
| ProofBench | 89.0% | 54.0% | Claude Haiku 5.5 |
| LMArena Text: math | Not measured | 1478 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: mathematical work | Not measured | 1485 | Only DeepSeek V4.1 Flash measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| LegalBench (Vals AI) | Not measured | 83.3% | Only DeepSeek V4.1 Flash measured |
| MedCode (Vals AI) | 51.5% | 41.2% | Claude Haiku 5.5 |
| SimpleQA Verified | 23.8% | 42.9% | DeepSeek V4.1 Flash |
| LMArena Text: science | Not measured | 1469 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: medicine and healthcare | Not measured | 1484 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: legal and government | Not measured | 1443 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: business and finance | Not measured | 1461 | Only DeepSeek V4.1 Flash measured |
| Neither model has a result on the other 10 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index25
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| Design Arena: websites | 1263 | 1309 | DeepSeek V4.1 Flash |
| Design Arena: UI components | 1295 | 1314 | DeepSeek V4.1 Flash |
| Design Arena: game dev | 1315 | 1331 | DeepSeek V4.1 Flash |
| Design Arena: data viz | 1292 | 1290 | Claude Haiku 5.5 |
| Design Arena: 3D | 1343 | 1356 | DeepSeek V4.1 Flash |
| Design Arena: all code categories | 1279 | 1320 | DeepSeek V4.1 Flash |
| Design Arena: SVG | Not measured | 1243 | Only DeepSeek V4.1 Flash measured |
| Design Arena: ASCII art | Not measured | 1265 | Only DeepSeek V4.1 Flash measured |
| LiveBench design | 83.1% | 79.2% | Claude Haiku 5.5 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index44
| Benchmark | Claude Haiku 5.5 | DeepSeek V4.1 Flash | Leader |
|---|---|---|---|
| Vals Index | 58.7% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench data analysis | 53.1% | 79.3% | DeepSeek V4.1 Flash |
| Public Benefits Bench (Vals AI) | 63.2% | 64.3% | DeepSeek V4.1 Flash |
| SAGE (Vals AI) | 45.8% | 47.9% | DeepSeek V4.1 Flash |
| MedScribe (Vals AI) | 89.5% | 85.5% | Claude Haiku 5.5 |
| Long context reasoning (AA-LCR) | 82.7% | 84.0% | DeepSeek V4.1 Flash |
| DTBench | 95.0% | 89.9% | Claude Haiku 5.5 |
| LMCA | 51.1% | 47.0% | Claude Haiku 5.5 |
| Surface Evolver Bench | Not measured | 46.3% | Only DeepSeek V4.1 Flash measured |
| Furniture assembly | 47.5% | 34.2% | Claude Haiku 5.5 |
| LMArena Text | Not measured | 1464 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: instruction following | Not measured | 1473 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: creative writing | Not measured | 1437 | Only DeepSeek V4.1 Flash measured |
| LMArena Vision | Not measured | 1278 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: English | Not measured | 1473 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: non-English | Not measured | 1449 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: Chinese | Not measured | 1501 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: German | Not measured | 1470 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: Japanese | Not measured | 1432 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: Korean | Not measured | 1436 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: French | Not measured | 1465 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: Spanish | Not measured | 1459 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: Russian | Not measured | 1467 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: Polish | Not measured | 1457 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: multi-turn | Not measured | 1461 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: longer queries | Not measured | 1473 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: writing and language | Not measured | 1450 | Only DeepSeek V4.1 Flash measured |
| LMArena Text: entertainment and media | Not measured | 1445 | Only DeepSeek V4.1 Flash measured |
| 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 Haiku 5.5 | 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 Haiku 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Maker | Anthropic | DeepSeek |
| Weights | No public weights listed | Open weights |
| Released | October 7, 2026 | September 10, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $0.10 | $0.049 |
| Output $/Mtok | $0.50 | $0.525 |
| Coding index | 75.9 | 77.2 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Haiku 5.5 better than DeepSeek V4.1 Flash for coding?
Claude Haiku 5.5 and DeepSeek V4.1 Flash are level for coding, 75.9 against 77.2 on the Vibe Coding Index, so price and context decide. Pick Claude Haiku 5.5 when output tokens cost 1.1x less, or when what matters is LiveBench coding or Terminal-Bench 4 (Vals AI), where it leads. Pick DeepSeek V4.1 Flash when the context window is larger, 1.05M against 1M tokens, or when what matters is LMArena WebDev or Code migration (Vals AI), where it leads.
Which is cheaper, Claude Haiku 5.5 or DeepSeek V4.1 Flash?
Claude Haiku 5.5 costs $0.10 per million input tokens and $0.50 per million output tokens; DeepSeek V4.1 Flash costs $0.049 and $0.525. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Haiku 5.5 or DeepSeek V4.1 Flash?
DeepSeek V4.1 Flash, with 1.05M tokens against 1M.
How many benchmarks is the Claude Haiku 5.5 vs DeepSeek V4.1 Flash comparison based on?
57 benchmarks have a result for both models as of October 21, 2026. Claude Haiku 5.5's coding index rests on 2 independent benchmarks and DeepSeek V4.1 Flash's on 2. Where only one model has a result, the page says so instead of naming a winner.