Claude Sonnet 5 vs DeepSeek V4 Flash 0731

Claude Sonnet 5 leads DeepSeek V4 Flash 0731 on coding, 57.7 to 51.8 on the Vibe Coding Index, and DeepSeek V4 Flash 0731 costs 35.7x less per output token ($0.28 vs $10.00 per million). Updated October 21, 2026; 52 benchmarks have a result for both.

Replace Claude Sonnet 5 Replace DeepSeek V4 Flash 0731

Claude Sonnet 5Anthropic

Coding: 57.7
Overall: 63.2
Output $/M: $10.00

DeepSeek V4 Flash 0731DeepSeek

Coding: 51.8
Overall: 55.2
Output $/M: $0.28

vs boards won of 52 shared, 1 tied

Claude Sonnet 5 or DeepSeek V4 Flash 0731: which to pick

Pick Claude Sonnet 5 for coding: it scores 57.7 on the Vibe Coding Index against 51.8 for DeepSeek V4 Flash 0731.

Pick DeepSeek V4 Flash 0731 for output tokens 35.7x cheaper ($0.28 vs $10.00 per million) and a lower cost per solved task ($0.01 against $1.87).

Model AClaude Sonnet 5Anthropic57.7/1006 independent benchmarks$1.87 per solved task Model BDeepSeek V4 Flash 0731DeepSeek51.8/1004 independent benchmarks$0.01 per solved task

52693

Shared results: 52
Claude Sonnet 5 only: 69
DeepSeek V4 Flash 0731 only: 3
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 Sonnet 5
Claude Sonnet 5 scores 57.7 against 51.8.
6 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Sonnet 5
Claude Sonnet 5 leads, 38.2 against 34.3.
Same board, both measured
Agentic work
AA Agentic Index
Claude Sonnet 5
Claude Sonnet 5 leads, 43.6 against 41.0.
Same board, both measured
Reasoning
GPQA Diamond
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 leads, 89.9% against 88.9%.
Same board, both measured
Knowledge
MMLU Pro
Claude Sonnet 5
Claude Sonnet 5 leads, 87.5% against 86.2%.
Same board, both measured
Web design
Design Arena: websites
Claude Sonnet 5
Claude Sonnet 5 leads, 1274 against 1238.
Same board, both measured
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 Sonnet 5 $0.0070, DeepSeek V4 Flash 0731 $0.0003 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
DeepSeek V4 Flash 0731
Claude Sonnet 5 $1.87, DeepSeek V4 Flash 0731 $0.01.
Published attempt cost and pass rate

At a glance

Coding index: Claude Sonnet 5 57.7 from 6 benchmarks, DeepSeek V4 Flash 0731 51.8 from 4 benchmarks.
Widest category: Math, 8.6 points apart on average over 4 shared benchmarks.
Widest single gap: FrontierCode: Claude Sonnet 5 42.7% against DeepSeek V4 Flash 0731 18.8%, 36.8 points apart on a 0 to 100 scale.
Output price: Claude Sonnet 5 $10.00 against DeepSeek V4 Flash 0731 $0.28 per million output tokens, 35.7x apart.
Context window: Claude Sonnet 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.

Boards won, where both have a result
Category	Claude Sonnet 5	DeepSeek V4 Flash 0731	Ties
Coding	9	5	1 tie
Intelligence	2	0
Agentic work	6	0
Reasoning	4	3
Math	4	0
Knowledge	6	0
Web design	8	0
General	3	1
All shared boards	42	9	1 tie

CodingLike-for-likeSix of these boards feed the Vibe Coding Index95

Coding benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
LiveBench coding	74.7%	Not measured	Only Claude Sonnet 5 measured
LMArena WebDev	1540	Not measured	Only Claude Sonnet 5 measured
AA Coding Index	71.5	69.1	Claude Sonnet 5
LiveCodeBench (Vals AI)	82.4%	87.3%	DeepSeek V4 Flash 0731
SWE-bench Verified (Vals AI)	79.6%	88.8%	DeepSeek V4 Flash 0731
Terminal-Bench 4 (Vals AI)	10.6%	18.7%	DeepSeek V4 Flash 0731
Vibe Code Bench (Vals AI)	81.3%	74.7%	Claude Sonnet 5
Code migration (Vals AI)	44.4%	38.6%	Claude Sonnet 5
ProgramBench (Vals AI)	0.0%	0.0%	Tie
IOI (Vals AI)	45.0%	32.7%	Claude Sonnet 5
Terminal-Bench 2.1 (Vals AI)	74.5%	67.0%	Claude Sonnet 5
Vibe Code Bench 1-100 (Vals AI)	13.8%	Not measured	Only Claude Sonnet 5 measured
SkillsBench (Vals AI)	46.5%	50.7%	DeepSeek V4 Flash 0731
CyberBench (Vals AI)	70.3%	72.1%	DeepSeek V4 Flash 0731
SciCode	54.3%	50.3%	Claude Sonnet 5
FrontierCode	42.7%	18.8%	Claude Sonnet 5
GSO-Bench	37.3%	Not measured	Only Claude Sonnet 5 measured
WeirdML	68.8%	63.0%	Claude Sonnet 5
ALE-Bench	1463.1	1306.1	Claude Sonnet 5
LMArena Text: coding	1483	Not measured	Only Claude Sonnet 5 measured
LMArena Text: software and IT	1474	Not measured	Only Claude Sonnet 5 measured
LMArena WebDev: React	1541	Not measured	Only Claude Sonnet 5 measured
LMArena WebDev: HTML	1527	Not measured	Only Claude Sonnet 5 measured
LMArena WebDev: from an image	1540	Not measured	Only Claude Sonnet 5 measured
SciCode	10.7%	Not measured	Only Claude Sonnet 5 measured
Neither model has a result on the other 14 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20

Intelligence benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
AA Intelligence Index	38.2	34.3	Claude Sonnet 5
Epoch Capabilities Index	156.9	154.8	Claude Sonnet 5

Agentic workLike-for-likePublic boards, shown as published, kept out of the index60

Agentic work benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
AA Agentic Index	43.6	41.0	Claude Sonnet 5
Design Arena: agents building web apps	1245	Not measured	Only Claude Sonnet 5 measured
Design Arena: agents building full-stack apps	1249	Not measured	Only Claude Sonnet 5 measured
Design Arena: agents building mobile apps	1215	Not measured	Only Claude Sonnet 5 measured
Design Arena: agents building Android apps	1225	Not measured	Only Claude Sonnet 5 measured
Design Arena: agents building Godot games	1225	Not measured	Only Claude Sonnet 5 measured
Design Arena: agents building games	1227	Not measured	Only Claude Sonnet 5 measured
Design Arena: HTML slides	1218	Not measured	Only Claude Sonnet 5 measured
Design Arena: PowerPoint slides	1216	Not measured	Only Claude Sonnet 5 measured
Design Arena: spreadsheets	1021	Not measured	Only Claude Sonnet 5 measured
LiveBench research	82.8%	Not measured	Only Claude Sonnet 5 measured
LiveBench browser	72.0%	Not measured	Only Claude Sonnet 5 measured
LiveBench long agentic	39.0%	Not measured	Only Claude Sonnet 5 measured
SREBench (Vals AI)	0.4%	Not measured	Only Claude Sonnet 5 measured
Finance Agent (Vals AI)	53.9%	49.5%	Claude Sonnet 5
Tax Agent Bench (Vals AI)	29.4%	28.1%	Claude Sonnet 5
Legal Research Bench (Vals AI)	41.8%	30.3%	Claude Sonnet 5
Excel Modeling Benchmark (Vals AI)	66.3%	57.0%	Claude Sonnet 5
BioMysteryBench (Vals AI)	Not measured	64.4%	Only DeepSeek V4 Flash 0731 measured
Terminal-Bench-Science (Vals AI)	5.7%	4.3%	Claude Sonnet 5
APEX-Agents	54.5%	Not measured	Only Claude Sonnet 5 measured
Vending-Bench 2	$6,378	Not measured	Only Claude Sonnet 5 measured
Neither model has a result on the other 19 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index43

Reasoning benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
GPQA Diamond	88.9%	89.9%	DeepSeek V4 Flash 0731
LiveBench reasoning	88.7%	Not measured	Only Claude Sonnet 5 measured
MMMU Pro (Vals AI)	83.0%	Not measured	Only Claude Sonnet 5 measured
GPQA Diamond (Artificial Analysis run)	91.1%	90.8%	Claude Sonnet 5
Humanity's Last Exam (Artificial Analysis run)	41.3%	38.6%	Claude Sonnet 5
GPQA Diamond (Epoch AI run)	90.5%	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	60.6%	61.1%	DeepSeek V4 Flash 0731
Chess puzzles	45.0%	32.0%	Claude Sonnet 5
Mystery game puzzles	35.0%	34.0%	Claude Sonnet 5
LMArena Text: hard prompts	1461	Not measured	Only Claude Sonnet 5 measured
LMArena Text: expert	1489	Not measured	Only Claude Sonnet 5 measured
LMArena Text: hard prompts in English	1464	Not measured	Only Claude Sonnet 5 measured
LMArena Vision: diagrams	1293	Not measured	Only Claude Sonnet 5 measured
LMArena Vision: homework	1311	Not measured	Only Claude Sonnet 5 measured
Neither model has a result on the other 6 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index40

Math benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
OTIS Mock AIME	94.7%	94.4%	Claude Sonnet 5
FrontierMath, tiers 1 to 3	65.6%	57.5%	Claude Sonnet 5
FrontierMath, tier 4	29.3%	24.4%	Claude Sonnet 5
ProofBench	77.0%	56.0%	Claude Sonnet 5
LMArena Text: math	1467	Not measured	Only Claude Sonnet 5 measured
LMArena Text: mathematical work	1481	Not measured	Only Claude Sonnet 5 measured
Neither model has a result on the other 7 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index60

Knowledge benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
MMLU Pro	87.5%	86.2%	Claude Sonnet 5
LegalBench (Vals AI)	83.9%	77.7%	Claude Sonnet 5
CorpFin (Vals AI)	67.0%	61.9%	Claude Sonnet 5
TaxEval (Vals AI)	75.6%	70.7%	Claude Sonnet 5
MortgageTax (Vals AI)	70.0%	Not measured	Only Claude Sonnet 5 measured
MedCode (Vals AI)	47.5%	41.4%	Claude Sonnet 5
SimpleQA Verified	33.7%	33.6%	Claude Sonnet 5
LMArena Text: science	1460	Not measured	Only Claude Sonnet 5 measured
LMArena Text: medicine and healthcare	1442	Not measured	Only Claude Sonnet 5 measured
LMArena Text: legal and government	1454	Not measured	Only Claude Sonnet 5 measured
LMArena Text: business and finance	1436	Not measured	Only Claude Sonnet 5 measured
Neither model has a result on the other 7 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index80

Web design benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
Design Arena: websites	1274	1238	Claude Sonnet 5
Design Arena: UI components	1280	1235	Claude Sonnet 5
Design Arena: game dev	1278	1208	Claude Sonnet 5
Design Arena: data viz	1251	1180	Claude Sonnet 5
Design Arena: 3D	1261	1209	Claude Sonnet 5
Design Arena: all code categories	1276	1230	Claude Sonnet 5
Design Arena: SVG	1193	1185	Claude Sonnet 5
Design Arena: ASCII art	1207	1090	Claude Sonnet 5
LiveBench design	82.0%	Not measured	Only Claude Sonnet 5 measured

GeneralLike-for-likePublic boards, shown as published, kept out of the index31

General benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 5	DeepSeek V4 Flash 0731	Leader
LiveBench data analysis	71.7%	Not measured	Only Claude Sonnet 5 measured
Public Benefits Bench (Vals AI)	66.0%	Not measured	Only Claude Sonnet 5 measured
SAGE (Vals AI)	48.9%	Not measured	Only Claude Sonnet 5 measured
MedScribe (Vals AI)	76.0%	80.4%	DeepSeek V4 Flash 0731
Vals Multimodal Index	68.8%	Not measured	Only Claude Sonnet 5 measured
Long context reasoning (AA-LCR)	82.0%	79.7%	Claude Sonnet 5
DTBench	92.5%	90.9%	Claude Sonnet 5
LMCA	50.0%	41.7%	Claude Sonnet 5
Surface Evolver Bench	60.0%	Not measured	Only Claude Sonnet 5 measured
LMArena Text	1442	Not measured	Only Claude Sonnet 5 measured
LMArena Text: instruction following	1452	Not measured	Only Claude Sonnet 5 measured
LMArena Text: creative writing	1416	Not measured	Only Claude Sonnet 5 measured
LMArena Vision	1273	Not measured	Only Claude Sonnet 5 measured
LMArena Text: English	1450	Not measured	Only Claude Sonnet 5 measured
LMArena Text: non-English	1431	Not measured	Only Claude Sonnet 5 measured
LMArena Text: Chinese	1478	Not measured	Only Claude Sonnet 5 measured
LMArena Text: German	1442	Not measured	Only Claude Sonnet 5 measured
LMArena Text: Japanese	1422	Not measured	Only Claude Sonnet 5 measured
LMArena Text: Korean	1412	Not measured	Only Claude Sonnet 5 measured
LMArena Text: French	1463	Not measured	Only Claude Sonnet 5 measured
LMArena Text: Spanish	1438	Not measured	Only Claude Sonnet 5 measured
LMArena Text: Russian	1450	Not measured	Only Claude Sonnet 5 measured
LMArena Text: Polish	1425	Not measured	Only Claude Sonnet 5 measured
LMArena Text: multi-turn	1453	Not measured	Only Claude Sonnet 5 measured
LMArena Text: longer queries	1462	Not measured	Only Claude Sonnet 5 measured
LMArena Text: writing and language	1436	Not measured	Only Claude Sonnet 5 measured
LMArena Text: entertainment and media	1411	Not measured	Only Claude Sonnet 5 measured
LMArena Vision: English	1275	Not measured	Only Claude Sonnet 5 measured
LMArena Vision: Chinese	1331	Not measured	Only Claude Sonnet 5 measured
LMArena Vision: reading text	1288	Not measured	Only Claude Sonnet 5 measured
LMArena Vision: humor	1261	Not measured	Only Claude Sonnet 5 measured
LMArena Vision: creative writing	1246	Not measured	Only Claude Sonnet 5 measured
LMArena Document	1466	Not measured	Only Claude Sonnet 5 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

Image generation benchmarks for Claude Sonnet 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Sonnet 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

Claude Sonnet 5$0.0070Fits in one request

DeepSeek V4 Flash 0731$0.0003Fits in one request

DeepSeek V4 Flash 0731 costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 5$0.130Fits in one request

DeepSeek V4 Flash 0731$0.0078Fits in one request

DeepSeek V4 Flash 0731 costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 5$0.500Fits in one request

DeepSeek V4 Flash 0731$0.031Fits in one request

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.

Specifications of Claude Sonnet 5 and DeepSeek V4 Flash 0731
Specification	Anthropic Claude Sonnet 5	DeepSeek V4 Flash 0731
Maker	Anthropic	DeepSeek
Weights	No public weights listed	Open weights
Released	June 30, 2026	July 31, 2026
Context window	1M	1.05M
Input $/Mtok	$2.00	$0.14
Output $/Mtok	$10.00	$0.28
Coding index	57.7	51.8
Independent measurements behind it	6	4
Cost per solved task	$1.87	$0.01
Source	OpenRouter listing	OpenRouter listing

Questions

Is Claude Sonnet 5 better than DeepSeek V4 Flash 0731 for coding?

Pick Claude Sonnet 5 for coding: it scores 57.7 on the Vibe Coding Index against 51.8 for DeepSeek V4 Flash 0731. Pick DeepSeek V4 Flash 0731 for output tokens 35.7x cheaper ($0.28 vs $10.00 per million) and a lower cost per solved task ($0.01 against $1.87).

Which is cheaper, Claude Sonnet 5 or DeepSeek V4 Flash 0731?

Claude Sonnet 5 costs $2.00 per million input tokens and $10.00 per million output tokens; DeepSeek V4 Flash 0731 costs $0.14 and $0.28. Per solved SWE-bench Verified task, Claude Sonnet 5 costs $1.87 and DeepSeek V4 Flash 0731 $0.01.

Which has the bigger context window, Claude Sonnet 5 or DeepSeek V4 Flash 0731?

DeepSeek V4 Flash 0731, with 1.05M tokens against 1M.

How many benchmarks is the Claude Sonnet 5 vs DeepSeek V4 Flash 0731 comparison based on?

52 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 5's coding index rests on 6 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.

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Claude Sonnet 5 or DeepSeek V4 Flash 0731: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Knowledge

Web design

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

Compare next