Claude Haiku 5.5 vs DeepSeek V4 Flash 0731
Claude Haiku 5.5 leads DeepSeek V4 Flash 0731 on coding, 70.7 to 51.8 on the Vibe Coding Index, and DeepSeek V4 Flash 0731 costs 1.8x less per output token ($0.28 vs $0.50 per million). Updated October 22, 2026; 38 benchmarks have a result for both.
Claude Haiku 5.5 or DeepSeek V4 Flash 0731: which to pick
Pick Claude Haiku 5.5 for coding: it scores 70.7 on the Vibe Coding Index against 51.8 for DeepSeek V4 Flash 0731.
Pick DeepSeek V4 Flash 0731 for output tokens 1.8x cheaper ($0.28 vs $0.50 per million) and a larger context window (1.05M against 1M tokens).
- Shared results
- 38
- Claude Haiku 5.5 only
- 27
- DeepSeek V4 Flash 0731 only
- 17
- 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 Haiku 5.5
Claude Haiku 5.5 scores 70.7 against 51.8.
5 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Haiku 5.5
Claude Haiku 5.5 leads, 43.4 against 34.3.
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
No call
Only DeepSeek V4 Flash 0731 has a GPQA Diamond result, 89.9%.
Directional only
Knowledge
MMLU Pro
No call
Only DeepSeek V4 Flash 0731 has a MMLU Pro result, 86.2%.
Directional only
Web design
Design Arena: websites
Claude Haiku 5.5
Claude Haiku 5.5 leads, 1262 against 1237.
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 Flash 0731
DeepSeek V4 Flash 0731 takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V4 Flash 0731
Claude Haiku 5.5 $0.0003, 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 Haiku 5.5 70.7 from 5 benchmarks, DeepSeek V4 Flash 0731 51.8 from 4 benchmarks.
- Widest category
- Math, 19.2 points apart on average over 4 shared benchmarks.
- Widest single gap
- FrontierCode: Claude Haiku 5.5 46.4% against DeepSeek V4 Flash 0731 18.8%, 42.4 points apart on a 0 to 100 scale.
- Output price
- Claude Haiku 5.5 $0.50 against DeepSeek V4 Flash 0731 $0.28 per million output tokens, 1.8x apart.
- Context window
- Claude Haiku 5.5 takes 1M 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 Haiku 5.5 | Bars | DeepSeek V4 Flash 0731 | Ties |
|---|---|---|---|---|
| Coding | 8 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 6 | 0 | ||
| Reasoning | 2 | 3 | 1 tie | |
| Math | 4 | 0 | ||
| Knowledge | 1 | 1 | ||
| Web design | 6 | 0 | ||
| General | 4 | 0 | ||
| All shared boards | 33 | 4 | 1 tie |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index80
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| LiveBench coding | 91.4% | Not measured | Only Claude Haiku 5.5 measured |
| LMArena WebDev | 1586 | Not measured | Only Claude Haiku 5.5 measured |
| AA Coding Index | Not measured | 69.1 | Only DeepSeek V4 Flash 0731 measured |
| LiveCodeBench (Vals AI) | Not measured | 87.3% | Only DeepSeek V4 Flash 0731 measured |
| SWE-bench Verified (Vals AI) | Not measured | 88.8% | Only DeepSeek V4 Flash 0731 measured |
| Terminal-Bench 4 (Vals AI) | 36.4% | 18.7% | Claude Haiku 5.5 |
| Vibe Code Bench (Vals AI) | 90.4% | 74.7% | Claude Haiku 5.5 |
| Code migration (Vals AI) | 44.6% | 38.6% | Claude Haiku 5.5 |
| ProgramBench (Vals AI) | 2.5% | 0.0% | Claude Haiku 5.5 |
| IOI (Vals AI) | 47.3% | 32.7% | Claude Haiku 5.5 |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 67.0% | Only DeepSeek V4 Flash 0731 measured |
| SWE-bench Multimodal (Vals AI) | 44.0% | Not measured | Only Claude Haiku 5.5 measured |
| Vibe Code Bench 1-100 (Vals AI) | 20.4% | Not measured | Only Claude Haiku 5.5 measured |
| SkillsBench (Vals AI) | Not measured | 50.7% | Only DeepSeek V4 Flash 0731 measured |
| CyberBench (Vals AI) | 75.5% | 72.1% | Claude Haiku 5.5 |
| SciCode | 55.0% | 50.3% | Claude Haiku 5.5 |
| FrontierCode | 46.4% | 18.8% | Claude Haiku 5.5 |
| FrontierSWE | 43.8% | Not measured | Only Claude Haiku 5.5 measured |
| WeirdML | Not measured | 63.0% | Only DeepSeek V4 Flash 0731 measured |
| ALE-Bench | Not measured | 1306.1 | Only DeepSeek V4 Flash 0731 measured |
| LMArena WebDev: React | 1605 | Not measured | Only Claude Haiku 5.5 measured |
| LMArena WebDev: HTML | 1569 | Not measured | Only Claude Haiku 5.5 measured |
| SciCode | 9.2% | Not measured | Only Claude Haiku 5.5 measured |
| SWE-Bench Pro V2 | 87.2% | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 19 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| AA Intelligence Index | 43.4 | 34.3 | Claude Haiku 5.5 |
| Epoch Capabilities Index | 159.3 | 154.8 | Claude Haiku 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 41.0 | Only DeepSeek V4 Flash 0731 measured |
| LiveBench research | 81.9% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench browser | 80.0% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench long agentic | 57.6% | Not measured | Only Claude Haiku 5.5 measured |
| SREBench (Vals AI) | 5.7% | Not measured | Only Claude Haiku 5.5 measured |
| Finance Agent (Vals AI) | 54.1% | 49.5% | Claude Haiku 5.5 |
| Tax Agent Bench (Vals AI) | 31.9% | 28.1% | Claude Haiku 5.5 |
| Legal Research Bench (Vals AI) | 43.3% | 30.3% | 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% | 57.0% | Claude Haiku 5.5 |
| BioMysteryBench (Vals AI) | 70.4% | 64.4% | Claude Haiku 5.5 |
| Terminal-Bench-Science (Vals AI) | 10.0% | 4.3% | Claude Haiku 5.5 |
| Vals Science Index | 38.5% | Not measured | Only Claude Haiku 5.5 measured |
| APEX-Agents | 56.1% | Not measured | Only Claude Haiku 5.5 measured |
| Vending-Bench 2 | $3,602 | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 27 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index23
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 89.9% | Only DeepSeek V4 Flash 0731 measured |
| LiveBench reasoning | 82.4% | Not measured | Only Claude Haiku 5.5 measured |
| MysteryMechanism (Vals AI) | 35.1% | Not measured | Only Claude Haiku 5.5 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 90.8% | Only DeepSeek V4 Flash 0731 measured |
| Humanity's Last Exam (Artificial Analysis run) | 44.4% | 38.6% | Claude Haiku 5.5 |
| GPQA Diamond (Epoch AI run) | 89.6% | 91.0% | DeepSeek V4 Flash 0731 |
| ARC-AGI | 89.0% | 89.0% | Tie |
| ARC-AGI-2 | 61.3% | 61.4% | DeepSeek V4 Flash 0731 |
| SimpleBench | Not measured | 61.1% | Only DeepSeek V4 Flash 0731 measured |
| Chess puzzles | 55.0% | 32.0% | Claude Haiku 5.5 |
| Mystery game puzzles | 30.0% | 34.0% | DeepSeek V4 Flash 0731 |
| EBR-bench | 43.8% | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 11 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| OTIS Mock AIME | 98.9% | 94.4% | Claude Haiku 5.5 |
| FrontierMath, tiers 1 to 3 | 75.1% | 57.5% | Claude Haiku 5.5 |
| FrontierMath, tier 4 | 46.3% | 24.4% | Claude Haiku 5.5 |
| ProofBench | 89.0% | 56.0% | Claude Haiku 5.5 |
| Neither model has a result on the other 10 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 86.2% | Only DeepSeek V4 Flash 0731 measured |
| LegalBench (Vals AI) | Not measured | 77.7% | Only DeepSeek V4 Flash 0731 measured |
| CorpFin (Vals AI) | Not measured | 61.9% | Only DeepSeek V4 Flash 0731 measured |
| TaxEval (Vals AI) | Not measured | 70.7% | Only DeepSeek V4 Flash 0731 measured |
| MedCode (Vals AI) | 51.5% | 41.4% | Claude Haiku 5.5 |
| SimpleQA Verified | 23.8% | 33.6% | DeepSeek V4 Flash 0731 |
| Neither model has a result on the other 14 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| Design Arena: websites | 1262 | 1237 | Claude Haiku 5.5 |
| Design Arena: UI components | 1283 | 1233 | Claude Haiku 5.5 |
| Design Arena: game dev | 1315 | 1207 | Claude Haiku 5.5 |
| Design Arena: data viz | 1297 | 1180 | Claude Haiku 5.5 |
| Design Arena: 3D | 1342 | 1208 | Claude Haiku 5.5 |
| Design Arena: all code categories | 1278 | 1229 | Claude Haiku 5.5 |
| Design Arena: SVG | Not measured | 1184 | Only DeepSeek V4 Flash 0731 measured |
| Design Arena: ASCII art | Not measured | 1090 | Only DeepSeek V4 Flash 0731 measured |
| LiveBench design | 83.1% | Not measured | Only Claude Haiku 5.5 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Haiku 5.5 | DeepSeek V4 Flash 0731 | Leader |
|---|---|---|---|
| Vals Index | 58.7% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench data analysis | 53.1% | Not measured | Only Claude Haiku 5.5 measured |
| Public Benefits Bench (Vals AI) | 63.2% | Not measured | Only Claude Haiku 5.5 measured |
| SAGE (Vals AI) | 45.8% | Not measured | Only Claude Haiku 5.5 measured |
| MedScribe (Vals AI) | 89.5% | 80.4% | Claude Haiku 5.5 |
| Long context reasoning (AA-LCR) | 82.7% | 79.7% | Claude Haiku 5.5 |
| DTBench | 95.0% | 90.9% | Claude Haiku 5.5 |
| LMCA | 51.1% | 41.7% | Claude Haiku 5.5 |
| Furniture assembly | 47.5% | Not measured | Only Claude Haiku 5.5 measured |
| MultiChallenge | 67.7% | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 38 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Haiku 5.5 | 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
Claude Haiku 5.5 costs less
Agent loop
200K input + 10K output tokens
Claude Haiku 5.5 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 Flash 0731 |
|---|---|---|
| Maker | Anthropic | DeepSeek |
| Weights | No public weights listed | Open weights |
| Released | October 7, 2026 | July 31, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $0.10 | $0.14 |
| Output $/Mtok | $0.50 | $0.28 |
| Coding index | 70.7 | 51.8 |
| Independent measurements behind it | 5 | 4 |
| Cost per solved task | Not computable | $0.01 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Haiku 5.5 better than DeepSeek V4 Flash 0731 for coding?
Pick Claude Haiku 5.5 for coding: it scores 70.7 on the Vibe Coding Index against 51.8 for DeepSeek V4 Flash 0731. Pick DeepSeek V4 Flash 0731 for output tokens 1.8x cheaper ($0.28 vs $0.50 per million) and a larger context window (1.05M against 1M tokens).
Which is cheaper, Claude Haiku 5.5 or DeepSeek V4 Flash 0731?
Claude Haiku 5.5 costs $0.10 per million input tokens and $0.50 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 Haiku 5.5 or DeepSeek V4 Flash 0731?
DeepSeek V4 Flash 0731, with 1.05M tokens against 1M.
How many benchmarks is the Claude Haiku 5.5 vs DeepSeek V4 Flash 0731 comparison based on?
38 benchmarks have a result for both models as of October 22, 2026. Claude Haiku 5.5's coding index rests on 5 independent benchmarks and DeepSeek V4 Flash 0731's on 4. Where only one model has a result, the page says so instead of naming a winner.