Claude Opus 4.5 vs DeepSeek V4 Flash 0731

DeepSeek V4 Flash 0731 leads Claude Opus 4.5 on coding, 51.8 to 44.0 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; 37 benchmarks have a result for both.

Replace Claude Opus 4.5 Replace DeepSeek V4 Flash 0731

Claude Opus 4.5Anthropic

Coding: 44.0
Overall: 55.7
Output $/M: $25.00

DeepSeek V4 Flash 0731DeepSeek

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

vs boards won of 37 shared

Claude Opus 4.5 or DeepSeek V4 Flash 0731: which to pick

Pick DeepSeek V4 Flash 0731 for coding: it scores 51.8 on the Vibe Coding Index against 44.0 for Claude Opus 4.5.

Pick Claude Opus 4.5 for work measured by WeirdML or SimpleBench, where it leads.

Model AClaude Opus 4.5Anthropic44.0/1003 independent benchmarks$1.37 per solved task Model BDeepSeek V4 Flash 0731DeepSeek51.8/1004 independent benchmarks$0.01 per solved task

377118

Shared results: 37
Claude Opus 4.5 only: 71
DeepSeek V4 Flash 0731 only: 18
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
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 scores 51.8 against 44.0.
3 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 leads, 34.3 against 29.1.
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
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 leads, 89.9% against 85.9%.
Same board, both measured
Math
AIME
No call
Only Claude Opus 4.5 has a AIME result, 95.4%.
Directional only
Knowledge
MMLU Pro
Claude Opus 4.5
Claude Opus 4.5 leads, 87.3% against 86.2%.
Same board, both measured
Web design
Design Arena: websites
Claude Opus 4.5
Claude Opus 4.5 leads, 1247 against 1238.
Same board, both measured
Long documents
Listed context window
DeepSeek V4 Flash 0731
DeepSeek V4 Flash 0731 takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V4 Flash 0731
Claude Opus 4.5 $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 4.5 $1.37, DeepSeek V4 Flash 0731 $0.01.
Published attempt cost and pass rate

At a glance

Coding index: Claude Opus 4.5 44.0 from 3 benchmarks, DeepSeek V4 Flash 0731 51.8 from 4 benchmarks.
Widest category: Math, 17.8 points apart on average over 4 shared benchmarks.
Widest single gap: Vibe Code Bench (Vals AI): Claude Opus 4.5 20.6% against DeepSeek V4 Flash 0731 74.7%, 54.1 points apart on a 0 to 100 scale.
Output price: Claude Opus 4.5 $25.00 against DeepSeek V4 Flash 0731 $0.28 per million output tokens, 89.3x apart.
Context window: Claude Opus 4.5 takes 200K 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 4.5	DeepSeek V4 Flash 0731
Coding	1	3
Intelligence	0	2
Reasoning	1	8
Math	0	4
Knowledge	6	0
Web design	7	1
General	2	2
All shared boards	17	20

CodingLike-for-likeSix of these boards feed the Vibe Coding Index13

Coding benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	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	Not measured	Only Claude Opus 4.5 measured
AA Coding Index	Not measured	69.1	Only DeepSeek V4 Flash 0731 measured
LiveCodeBench (Vals AI)	83.7%	87.3%	DeepSeek V4 Flash 0731
SWE-bench Verified (Vals AI)	76.4%	88.8%	DeepSeek V4 Flash 0731
Terminal-Bench 4 (Vals AI)	Not measured	18.7%	Only DeepSeek V4 Flash 0731 measured
Vibe Code Bench (Vals AI)	20.6%	74.7%	DeepSeek V4 Flash 0731
Code migration (Vals AI)	Not measured	38.6%	Only DeepSeek V4 Flash 0731 measured
ProgramBench (Vals AI)	Not measured	0.0%	Only DeepSeek V4 Flash 0731 measured
IOI (Vals AI)	Not measured	32.7%	Only DeepSeek V4 Flash 0731 measured
Terminal-Bench 2.1 (Vals AI)	Not measured	67.0%	Only DeepSeek V4 Flash 0731 measured
SkillsBench (Vals AI)	Not measured	50.7%	Only DeepSeek V4 Flash 0731 measured
CyberBench (Vals AI)	Not measured	72.1%	Only DeepSeek V4 Flash 0731 measured
LiveCodeBench (Artificial Analysis run)	87.1%	Not measured	Only Claude Opus 4.5 measured
SciCode	Not measured	50.3%	Only DeepSeek V4 Flash 0731 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
FrontierCode	Not measured	18.8%	Only DeepSeek V4 Flash 0731 measured
GSO-Bench	26.5%	Not measured	Only Claude Opus 4.5 measured
WeirdML	63.7%	63.0%	Claude Opus 4.5
Cybench	82.0%	Not measured	Only Claude Opus 4.5 measured
ALE-Bench	Not measured	1306.1	Only DeepSeek V4 Flash 0731 measured
LMArena Text: coding	1503	Not measured	Only Claude Opus 4.5 measured
LMArena Text: software and IT	1483	Not measured	Only Claude Opus 4.5 measured
LMArena WebDev: React	1478	Not measured	Only Claude Opus 4.5 measured
LMArena WebDev: HTML	1510	Not measured	Only Claude Opus 4.5 measured
Neither model has a result on the other 11 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02

Intelligence benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	Leader
AA Intelligence Index	29.1	34.3	DeepSeek V4 Flash 0731
Epoch Capabilities Index	150.1	154.8	DeepSeek V4 Flash 0731

Agentic workDirectional onlyPublic boards, shown as published, kept out of the index20 boards, none shared

Agentic work benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	Leader
AA Agentic Index	Not measured	41.0	Only DeepSeek V4 Flash 0731 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	1175	Not measured	Only Claude Opus 4.5 measured
Finance Agent (Vals AI)	Not measured	49.5%	Only DeepSeek V4 Flash 0731 measured
Tax Agent Bench (Vals AI)	Not measured	28.1%	Only DeepSeek V4 Flash 0731 measured
Legal Research Bench (Vals AI)	Not measured	30.3%	Only DeepSeek V4 Flash 0731 measured
Excel Modeling Benchmark (Vals AI)	Not measured	57.0%	Only DeepSeek V4 Flash 0731 measured
BioMysteryBench (Vals AI)	Not measured	64.4%	Only DeepSeek V4 Flash 0731 measured
Terminal-Bench-Science (Vals AI)	Not measured	4.3%	Only DeepSeek V4 Flash 0731 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 21 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index18

Reasoning benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	Leader
GPQA Diamond	85.9%	89.9%	DeepSeek V4 Flash 0731
MMMU Pro (Vals AI)	83.0%	Not measured	Only Claude Opus 4.5 measured
GPQA Diamond (Artificial Analysis run)	86.6%	90.8%	DeepSeek V4 Flash 0731
Humanity's Last Exam (Artificial Analysis run)	30.1%	38.6%	DeepSeek V4 Flash 0731
GPQA Diamond (Epoch AI run)	86.0%	91.0%	DeepSeek V4 Flash 0731
ARC-AGI	80.0%	89.0%	DeepSeek V4 Flash 0731
ARC-AGI-2	37.6%	61.4%	DeepSeek V4 Flash 0731
SimpleBench	62.0%	61.1%	Claude Opus 4.5
Chess puzzles	14.0%	32.0%	DeepSeek V4 Flash 0731
Mystery game puzzles	22.0%	34.0%	DeepSeek V4 Flash 0731
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	Not measured	Only Claude Opus 4.5 measured
LMArena Text: expert	1487	Not measured	Only Claude Opus 4.5 measured
LMArena Text: hard prompts in English	1482	Not measured	Only Claude Opus 4.5 measured
Kagi LLM Benchmark	80.2%	Not measured	Only Claude Opus 4.5 measured
Neither model has a result on the other 6 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index04

Math benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	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%	94.4%	DeepSeek V4 Flash 0731
FrontierMath, tiers 1 to 3	34.4%	57.5%	DeepSeek V4 Flash 0731
FrontierMath, tier 4	4.9%	24.4%	DeepSeek V4 Flash 0731
ProofBench	36.0%	56.0%	DeepSeek V4 Flash 0731
LMArena Text: math	1463	Not measured	Only Claude Opus 4.5 measured
LMArena Text: mathematical work	1468	Not measured	Only Claude Opus 4.5 measured
Neither model has a result on the other 3 boards here

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

Knowledge benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	Leader
MMLU Pro	87.3%	86.2%	Claude Opus 4.5
LegalBench (Vals AI)	84.6%	77.7%	Claude Opus 4.5
CaseLaw (Vals AI)	62.6%	Not measured	Only Claude Opus 4.5 measured
CorpFin (Vals AI)	65.1%	61.9%	Claude Opus 4.5
TaxEval (Vals AI)	74.9%	70.7%	Claude Opus 4.5
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%	41.4%	Claude Opus 4.5
MMLU Pro (Artificial Analysis run)	89.5%	Not measured	Only Claude Opus 4.5 measured
SimpleQA Verified	45.7%	33.6%	Claude Opus 4.5
GeoBench	75.0%	Not measured	Only Claude Opus 4.5 measured
LMArena Text: science	1454	Not measured	Only Claude Opus 4.5 measured
LMArena Text: medicine and healthcare	1444	Not measured	Only Claude Opus 4.5 measured
LMArena Text: legal and government	1459	Not measured	Only Claude Opus 4.5 measured
LMArena Text: business and finance	1448	Not measured	Only Claude Opus 4.5 measured
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 index71

Web design benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	Leader
Design Arena: websites	1247	1238	Claude Opus 4.5
Design Arena: UI components	1238	1235	Claude Opus 4.5
Design Arena: game dev	1229	1208	Claude Opus 4.5
Design Arena: data viz	1243	1180	Claude Opus 4.5
Design Arena: 3D	1214	1209	Claude Opus 4.5
Design Arena: all code categories	1242	1230	Claude Opus 4.5
Design Arena: SVG	1181	1185	DeepSeek V4 Flash 0731
Design Arena: ASCII art	1190	1090	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 index22

General benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	DeepSeek V4 Flash 0731	Leader
SAGE (Vals AI)	52.1%	Not measured	Only Claude Opus 4.5 measured
MedScribe (Vals AI)	85.3%	80.4%	Claude Opus 4.5
IFBench	58.0%	Not measured	Only Claude Opus 4.5 measured
Long context reasoning (AA-LCR)	77.3%	79.7%	DeepSeek V4 Flash 0731
DTBench	89.9%	90.9%	DeepSeek V4 Flash 0731
LMCA	44.5%	41.7%	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	Not measured	Only Claude Opus 4.5 measured
LMArena Text: instruction following	1478	Not measured	Only Claude Opus 4.5 measured
LMArena Text: creative writing	1445	Not measured	Only Claude Opus 4.5 measured
LMArena Text: English	1461	Not measured	Only Claude Opus 4.5 measured
LMArena Text: non-English	1438	Not measured	Only Claude Opus 4.5 measured
LMArena Text: Chinese	1470	Not measured	Only Claude Opus 4.5 measured
LMArena Text: German	1449	Not measured	Only Claude Opus 4.5 measured
LMArena Text: Japanese	1417	Not measured	Only Claude Opus 4.5 measured
LMArena Text: Korean	1424	Not measured	Only Claude Opus 4.5 measured
LMArena Text: French	1471	Not measured	Only Claude Opus 4.5 measured
LMArena Text: Spanish	1457	Not measured	Only Claude Opus 4.5 measured
LMArena Text: Russian	1447	Not measured	Only Claude Opus 4.5 measured
LMArena Text: Polish	1439	Not measured	Only Claude Opus 4.5 measured
LMArena Text: multi-turn	1466	Not measured	Only Claude Opus 4.5 measured
LMArena Text: longer queries	1479	Not measured	Only Claude Opus 4.5 measured
LMArena Text: writing and language	1452	Not measured	Only Claude Opus 4.5 measured
LMArena Text: entertainment and media	1434	Not measured	Only Claude Opus 4.5 measured
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

Image generation benchmarks for Claude Opus 4.5 and DeepSeek V4 Flash 0731
Benchmark	Claude Opus 4.5	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 4.5$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 4.5$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 4.5$1.25Exceeds the context window

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 4.5 and DeepSeek V4 Flash 0731
Specification	Anthropic Claude Opus 4.5	DeepSeek V4 Flash 0731
Maker	Anthropic	DeepSeek
Weights	No public weights listed	Open weights
Released	November 24, 2025	July 31, 2026
Context window	200K	1.05M
Input $/Mtok	$5.00	$0.14
Output $/Mtok	$25.00	$0.28
Coding index	44.0	51.8
Independent measurements behind it	3	4
Cost per solved task	$1.37	$0.01
Source	OpenRouter listing	OpenRouter listing

Questions

Is Claude Opus 4.5 better than DeepSeek V4 Flash 0731 for coding?

Pick DeepSeek V4 Flash 0731 for coding: it scores 51.8 on the Vibe Coding Index against 44.0 for Claude Opus 4.5. Pick Claude Opus 4.5 for work measured by WeirdML or SimpleBench, where it leads.

Which is cheaper, Claude Opus 4.5 or DeepSeek V4 Flash 0731?

Claude Opus 4.5 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 4.5 costs $1.37 and DeepSeek V4 Flash 0731 $0.01.

Which has the bigger context window, Claude Opus 4.5 or DeepSeek V4 Flash 0731?

DeepSeek V4 Flash 0731, with 1.05M tokens against 200K.

How many benchmarks is the Claude Opus 4.5 vs DeepSeek V4 Flash 0731 comparison based on?

37 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.5's coding index rests on 3 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 4.5 or DeepSeek V4 Flash 0731: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Math

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