Claude Opus 5 vs DeepSeek V4 Flash 0731

Claude Opus 5 leads DeepSeek V4 Flash 0731 on coding, 83.0 to 51.8 on the Vibe Coding Index, and DeepSeek V4 Flash 0731 costs 89.3x less per output token ($0.28 vs $25.00 per million). Updated October 21, 2026; 55 benchmarks have a result for both.

Replace Claude Opus 5 Replace DeepSeek V4 Flash 0731

Claude Opus 5Anthropic

Coding: 83.0
Overall: 81.6
Output $/M: $25.00

DeepSeek V4 Flash 0731DeepSeek

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

vs boards won of 55 shared

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

Pick Claude Opus 5 for coding: it scores 83.0 on the Vibe Coding Index against 51.8 for DeepSeek V4 Flash 0731.

Pick DeepSeek V4 Flash 0731 for output tokens 89.3x cheaper ($0.28 vs $25.00 per million) and a lower cost per solved task ($0.01 against $1.33).

Model AClaude Opus 5Anthropic83.0/1006 independent benchmarks$1.33 per solved task Model BDeepSeek V4 Flash 0731DeepSeek51.8/1004 independent benchmarks$0.01 per solved task

5576

Shared results: 55
Claude Opus 5 only: 76
DeepSeek V4 Flash 0731 only: 0
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 Opus 5
Claude Opus 5 scores 83.0 against 51.8.
6 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Opus 5
Claude Opus 5 leads, 50.8 against 34.3.
Same board, both measured
Agentic work
AA Agentic Index
Claude Opus 5
Claude Opus 5 leads, 56.5 against 41.0.
Same board, both measured
Reasoning
GPQA Diamond
Claude Opus 5
Claude Opus 5 leads, 93.4% against 89.9%.
Same board, both measured
Knowledge
MMLU Pro
Claude Opus 5
Claude Opus 5 leads, 91.6% against 86.2%.
Same board, both measured
Web design
Design Arena: websites
Claude Opus 5
Claude Opus 5 leads, 1309 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 Opus 5 $0.018, 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 Opus 5 $1.33, DeepSeek V4 Flash 0731 $0.01.
Published attempt cost and pass rate

At a glance

Coding index: Claude Opus 5 83.0 from 6 benchmarks, DeepSeek V4 Flash 0731 51.8 from 4 benchmarks.
Widest category: Math, 31.1 points apart on average over 4 shared benchmarks.
Widest single gap: FrontierCode: Claude Opus 5 53.4% against DeepSeek V4 Flash 0731 18.8%, 53.2 points apart on a 0 to 100 scale.
Output price: Claude Opus 5 $25.00 against DeepSeek V4 Flash 0731 $0.28 per million output tokens, 89.3x apart.
Context window: Claude Opus 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 Opus 5	DeepSeek V4 Flash 0731
Coding	14	1
Intelligence	2	0
Agentic work	7	0
Reasoning	9	0
Math	4	0
Knowledge	6	0
Web design	8	0
General	4	0
All shared boards	54	1

CodingLike-for-likeSix of these boards feed the Vibe Coding Index141

Coding benchmarks for Claude Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
LiveBench coding	90.8%	Not measured	Only Claude Opus 5 measured
LMArena WebDev	1689	Not measured	Only Claude Opus 5 measured
AA Coding Index	78.0	69.1	Claude Opus 5
LiveCodeBench (Vals AI)	89.0%	87.3%	Claude Opus 5
SWE-bench Verified (Vals AI)	97.0%	88.8%	Claude Opus 5
Terminal-Bench 4 (Vals AI)	53.5%	18.7%	Claude Opus 5
Vibe Code Bench (Vals AI)	88.4%	74.7%	Claude Opus 5
Code migration (Vals AI)	57.5%	38.6%	Claude Opus 5
ProgramBench (Vals AI)	3.0%	0.0%	Claude Opus 5
IOI (Vals AI)	84.3%	32.7%	Claude Opus 5
Terminal-Bench 2.1 (Vals AI)	84.6%	67.0%	Claude Opus 5
Vibe Code Bench 1-100 (Vals AI)	28.5%	Not measured	Only Claude Opus 5 measured
SkillsBench (Vals AI)	60.4%	50.7%	Claude Opus 5
CyberBench (Vals AI)	65.4%	72.1%	DeepSeek V4 Flash 0731
SciCode	56.4%	50.3%	Claude Opus 5
FrontierCode	53.4%	18.8%	Claude Opus 5
FrontierSWE	52.0%	Not measured	Only Claude Opus 5 measured
WeirdML	91.8%	63.0%	Claude Opus 5
ALE-Bench	2164.6	1306.1	Claude Opus 5
LMArena Text: coding	1533	Not measured	Only Claude Opus 5 measured
LMArena Text: software and IT	1527	Not measured	Only Claude Opus 5 measured
LMArena WebDev: React	1711	Not measured	Only Claude Opus 5 measured
LMArena WebDev: HTML	1680	Not measured	Only Claude Opus 5 measured
LMArena WebDev: from an image	1662	Not measured	Only Claude Opus 5 measured
SciCode	13.8%	Not measured	Only Claude Opus 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 Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
AA Intelligence Index	50.8	34.3	Claude Opus 5
Epoch Capabilities Index	163.9	154.8	Claude Opus 5

Agentic workLike-for-likePublic boards, shown as published, kept out of the index70

Agentic work benchmarks for Claude Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
AA Agentic Index	56.5	41.0	Claude Opus 5
Design Arena: agents building web apps	1266	Not measured	Only Claude Opus 5 measured
Design Arena: agents building full-stack apps	1306	Not measured	Only Claude Opus 5 measured
Design Arena: agents building mobile apps	1348	Not measured	Only Claude Opus 5 measured
Design Arena: agents building Android apps	1254	Not measured	Only Claude Opus 5 measured
Design Arena: agents building Godot games	1279	Not measured	Only Claude Opus 5 measured
Design Arena: agents building games	1261	Not measured	Only Claude Opus 5 measured
Design Arena: PowerPoint slides	1265	Not measured	Only Claude Opus 5 measured
LiveBench research	88.9%	Not measured	Only Claude Opus 5 measured
LiveBench browser	84.0%	Not measured	Only Claude Opus 5 measured
LiveBench long agentic	62.1%	Not measured	Only Claude Opus 5 measured
SREBench (Vals AI)	12.2%	Not measured	Only Claude Opus 5 measured
Finance Agent (Vals AI)	58.6%	49.5%	Claude Opus 5
Tax Agent Bench (Vals AI)	45.5%	28.1%	Claude Opus 5
Legal Research Bench (Vals AI)	55.3%	30.3%	Claude Opus 5
Excel Modeling Benchmark (Vals AI)	73.6%	57.0%	Claude Opus 5
BioMysteryBench (Vals AI)	79.3%	64.4%	Claude Opus 5
Terminal-Bench-Science (Vals AI)	27.1%	4.3%	Claude Opus 5
Vals Science Index	47.9%	Not measured	Only Claude Opus 5 measured
Time Horizon Index (Vals AI)	18.8%	Not measured	Only Claude Opus 5 measured
CUA-bench (Vals AI)	9.0%	Not measured	Only Claude Opus 5 measured
APEX-Agents	65.8%	Not measured	Only Claude Opus 5 measured
OSWorld 2.0	31.4%	Not measured	Only Claude Opus 5 measured
BALROG	63.4%	Not measured	Only Claude Opus 5 measured
PostTrainBench	35.0%	Not measured	Only Claude Opus 5 measured
Vending-Bench 2	$11,182	Not measured	Only Claude Opus 5 measured
LMArena Search	1242	Not measured	Only Claude Opus 5 measured
Neither model has a result on the other 14 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index90

Reasoning benchmarks for Claude Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
GPQA Diamond	93.4%	89.9%	Claude Opus 5
LiveBench reasoning	91.2%	Not measured	Only Claude Opus 5 measured
MysteryMechanism (Vals AI)	37.4%	Not measured	Only Claude Opus 5 measured
MMMU Pro (Vals AI)	89.9%	Not measured	Only Claude Opus 5 measured
GPQA Diamond (Artificial Analysis run)	93.7%	90.8%	Claude Opus 5
Humanity's Last Exam (Artificial Analysis run)	54.9%	38.6%	Claude Opus 5
GPQA Diamond (Epoch AI run)	93.9%	91.0%	Claude Opus 5
ARC-AGI	97.5%	89.0%	Claude Opus 5
ARC-AGI-2	90.4%	61.4%	Claude Opus 5
SimpleBench	80.6%	61.1%	Claude Opus 5
Chess puzzles	43.0%	32.0%	Claude Opus 5
Mystery game puzzles	59.0%	34.0%	Claude Opus 5
EBR-bench	45.7%	Not measured	Only Claude Opus 5 measured
LMArena Text: hard prompts	1527	Not measured	Only Claude Opus 5 measured
LMArena Text: expert	1554	Not measured	Only Claude Opus 5 measured
LMArena Text: hard prompts in English	1523	Not measured	Only Claude Opus 5 measured
LMArena Vision: diagrams	1348	Not measured	Only Claude Opus 5 measured
LMArena Vision: homework	1338	Not measured	Only Claude Opus 5 measured
Neither model has a result on the other 4 boards here

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

Math benchmarks for Claude Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
OTIS Mock AIME	98.9%	94.4%	Claude Opus 5
FrontierMath, tiers 1 to 3	85.6%	57.5%	Claude Opus 5
FrontierMath, tier 4	73.2%	24.4%	Claude Opus 5
ProofBench	99.0%	56.0%	Claude Opus 5
LMArena Text: math	1533	Not measured	Only Claude Opus 5 measured
LMArena Text: mathematical work	1544	Not measured	Only Claude Opus 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 Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
MMLU Pro	91.6%	86.2%	Claude Opus 5
LegalBench (Vals AI)	87.0%	77.7%	Claude Opus 5
CorpFin (Vals AI)	73.2%	61.9%	Claude Opus 5
TaxEval (Vals AI)	75.1%	70.7%	Claude Opus 5
MortgageTax (Vals AI)	72.1%	Not measured	Only Claude Opus 5 measured
MedCode (Vals AI)	63.6%	41.4%	Claude Opus 5
SimpleQA Verified	59.9%	33.6%	Claude Opus 5
LMArena Text: science	1531	Not measured	Only Claude Opus 5 measured
LMArena Text: medicine and healthcare	1525	Not measured	Only Claude Opus 5 measured
LMArena Text: legal and government	1530	Not measured	Only Claude Opus 5 measured
LMArena Text: business and finance	1501	Not measured	Only Claude Opus 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 Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
Design Arena: websites	1309	1238	Claude Opus 5
Design Arena: UI components	1349	1235	Claude Opus 5
Design Arena: game dev	1338	1208	Claude Opus 5
Design Arena: data viz	1329	1180	Claude Opus 5
Design Arena: 3D	1335	1209	Claude Opus 5
Design Arena: all code categories	1324	1230	Claude Opus 5
Design Arena: SVG	1311	1185	Claude Opus 5
Design Arena: ASCII art	1352	1090	Claude Opus 5
LiveBench design	83.0%	Not measured	Only Claude Opus 5 measured

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

General benchmarks for Claude Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 5	DeepSeek V4 Flash 0731	Leader
LiveBench data analysis	74.6%	Not measured	Only Claude Opus 5 measured
Public Benefits Bench (Vals AI)	76.9%	Not measured	Only Claude Opus 5 measured
SAGE (Vals AI)	49.4%	Not measured	Only Claude Opus 5 measured
MedScribe (Vals AI)	91.0%	80.4%	Claude Opus 5
Vals Multimodal Index	73.9%	Not measured	Only Claude Opus 5 measured
Long context reasoning (AA-LCR)	82.0%	79.7%	Claude Opus 5
DTBench	97.9%	90.9%	Claude Opus 5
LMCA	64.5%	41.7%	Claude Opus 5
Furniture assembly	60.8%	Not measured	Only Claude Opus 5 measured
LMArena Text	1509	Not measured	Only Claude Opus 5 measured
LMArena Text: instruction following	1518	Not measured	Only Claude Opus 5 measured
LMArena Text: creative writing	1493	Not measured	Only Claude Opus 5 measured
LMArena Vision	1320	Not measured	Only Claude Opus 5 measured
LMArena Text: English	1508	Not measured	Only Claude Opus 5 measured
LMArena Text: non-English	1502	Not measured	Only Claude Opus 5 measured
LMArena Text: Chinese	1573	Not measured	Only Claude Opus 5 measured
LMArena Text: German	1527	Not measured	Only Claude Opus 5 measured
LMArena Text: Japanese	1520	Not measured	Only Claude Opus 5 measured
LMArena Text: Korean	1517	Not measured	Only Claude Opus 5 measured
LMArena Text: French	1519	Not measured	Only Claude Opus 5 measured
LMArena Text: Spanish	1523	Not measured	Only Claude Opus 5 measured
LMArena Text: Russian	1507	Not measured	Only Claude Opus 5 measured
LMArena Text: Polish	1522	Not measured	Only Claude Opus 5 measured
LMArena Text: multi-turn	1500	Not measured	Only Claude Opus 5 measured
LMArena Text: longer queries	1517	Not measured	Only Claude Opus 5 measured
LMArena Text: writing and language	1499	Not measured	Only Claude Opus 5 measured
LMArena Text: entertainment and media	1481	Not measured	Only Claude Opus 5 measured
LMArena Vision: English	1315	Not measured	Only Claude Opus 5 measured
LMArena Vision: Chinese	1400	Not measured	Only Claude Opus 5 measured
LMArena Vision: reading text	1329	Not measured	Only Claude Opus 5 measured
LMArena Vision: humor	1293	Not measured	Only Claude Opus 5 measured
LMArena Vision: creative writing	1313	Not measured	Only Claude Opus 5 measured
LMArena Document	1516	Not measured	Only Claude Opus 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 Opus 5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 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 Opus 5$0.018Fits 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 Opus 5$0.325Fits 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 Opus 5$1.25Fits 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 Opus 5 and DeepSeek V4 Flash 0731
Specification	Anthropic Claude Opus 5	DeepSeek V4 Flash 0731
Maker	Anthropic	DeepSeek
Weights	No public weights listed	Open weights
Released	July 24, 2026	July 31, 2026
Context window	1M	1.05M
Input $/Mtok	$5.00	$0.14
Output $/Mtok	$25.00	$0.28
Coding index	83.0	51.8
Independent measurements behind it	6	4
Cost per solved task	$1.33	$0.01
Source	OpenRouter listing	OpenRouter listing

Questions

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

Pick Claude Opus 5 for coding: it scores 83.0 on the Vibe Coding Index against 51.8 for DeepSeek V4 Flash 0731. Pick DeepSeek V4 Flash 0731 for output tokens 89.3x cheaper ($0.28 vs $25.00 per million) and a lower cost per solved task ($0.01 against $1.33).

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

Claude Opus 5 costs $5.00 per million input tokens and $25.00 per million output tokens; DeepSeek V4 Flash 0731 costs $0.14 and $0.28. Per solved SWE-bench Verified task, Claude Opus 5 costs $1.33 and DeepSeek V4 Flash 0731 $0.01.

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

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

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

55 benchmarks have a result for both models as of October 21, 2026. Claude Opus 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 Opus 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