AnthropicDeepSeekLLM matchup

Claude Opus 5.5vs.DeepSeek-V4-Flash

Which one is better?

DeepSeek-V4-Flash does not have enough benchmark results yet. DeepSeek-V4-Flash is cheaper: Claude Opus 5.5 costs 28.6 times (input) and 71.4 times (output) as much.

IntelligenceOverall index, 100 points = average

126.1

Claude Opus 5.5

Rank 1

n/a

DeepSeek-V4-Flash

not ranked yet

about as fast

SpeedTokens per second

106

Claude Opus 5.5

123

DeepSeek-V4-Flash

DeepSeek-V4-Flash cheaper

Price$ per 1M tokens

Claude Opus 5.5

$0.18

DeepSeek-V4-Flash

about as popular

Popularity0 to 100

Claude Opus 5.5

Rank 8 of 785

DeepSeek-V4-Flash

Rank 17 of 785

Choose Claude Opus 5.5 for

Agents

Choose DeepSeek-V4-Flash for

No clear advantage

Where is the difference?

Opus 5.5 is ahead in 1 of 10 areas, DeepSeek-V4-Flash in none.

Opus 5.5 ahead: 1too little data: 9

Areas in the overall index

AgentsOpus 5.5 +34117.2 to 83.2

Codingonly Opus 5.5 has a score

Reasoningonly Opus 5.5 has a score

Mathematicsonly Opus 5.5 has a score

Knowledgeonly Opus 5.5 has a score

Generalonly Opus 5.5 has a score

Multimodalonly Opus 5.5 has a score

Specialist fields

Financeonly Opus 5.5 has a score

Legalonly Opus 5.5 has a score

Healthonly Opus 5.5 has a score

Bar length shows the gap in index points (full width 15 points, one standard deviation of the reference group). Solid means clearly ahead, hatched not certain yet, a thin grey bar level.

Show 4 more areas that do not count toward the overall index

Cybersecurityonly Opus 5.5 has a score

Searchonly Opus 5.5 has a score

Productivityonly Opus 5.5 has a score

Educationonly Opus 5.5 has a score

Bar length shows the gap in index points (full width 15 points, one standard deviation of the reference group). Solid means clearly ahead, hatched not certain yet, a thin grey bar level.

Which model for which task?

Everyday tasks, translated from the area values above. Each row names the values it rests on.

TaskBetter choicebased on

Writing and debugging codeopenCoding without a score for DeepSeek-V4-Flash

Maths and data analysisopenMathematics without a score for DeepSeek-V4-Flash, Reasoning without a score for DeepSeek-V4-Flash

Facts and researchopenKnowledge without a score for DeepSeek-V4-Flash, Search without a score for DeepSeek-V4-Flash

Agents and workflowsOpus 5.5Agents 117.2 to 83.2

Fast chat repliesabout the same106 to 123 tokens per second

Security analysisopenCybersecurity without a score for DeepSeek-V4-Flash

Many requests on a small budgetDeepSeek-V4-Flash$8 to $0.18 per 1M tokens

Finance, legal and medical textsopenFinance without a score for DeepSeek-V4-Flash, Legal without a score for DeepSeek-V4-Flash, Health without a score for DeepSeek-V4-Flash

Images, screenshots and PDFsopenMultimodal without a score for DeepSeek-V4-Flash

See for yourself: same task, one attempt

The same prompt for both models. We show the latest attempt without fixes; it does not count toward the overall index.

Pelican on a bicycle

Prompt

Generate an SVG of a pelican riding a bicycle

Task origin: Simon Willison

Claude Opus 5.5

Oct 1, 2026 · 33 s · $0.07

Test details

Run date: Oct 1, 2026
API provider: openrouter
Requested API model: anthropic/claude-opus-5.5
Reasoning setting: high
Token limit including reasoning: 8,192 tokens
Output tokens: 3,536 tokens
Cost of the attempt: $0.0708
Response time: 33.2 s
API model reported in response: anthropic/claude-opus-5.5
Pinned endpoint: Anthropic | anthropic/claude-opus-5.5-20260921
Temperature: Provider default
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating

Visually reviewed. This individual test does not establish overall model quality.

DeepSeek-V4-Flash

The response reached the token limit. No complete recording is available.

Oct 5, 2026 · 98 s · $0.0011

Not yet visually reviewed. A successful recording does not confirm correct physics or full compliance with the prompt.

Test details

Run date: Oct 5, 2026
API provider: openrouter
Requested API model: deepseek/deepseek-v4-flash-0731
Reasoning setting: high
Token limit including reasoning: 8,192 tokens
Output tokens: 8,192 tokens
Cost of the attempt: $0.0011
Response time: 97.8 s
API model reported in response: deepseek/deepseek-v4-flash-0731
Pinned endpoint: StreamLake | deepseek/deepseek-v4-flash-20260731
Temperature: Provider default
Test protocol: community-visual-tests-v1
Technical checks: Failed

Earlier attempts (3)

Oct 2, 2026API request failedReasoning setting: high
Oct 1, 2026API request failedReasoning setting: high
Sep 7, 2026API request failedReasoning setting: high

SVG short test

One SVG task with the same fixed settings for every model, without hidden thinking.

Prompt

Return only one standalone SVG of a pelican riding a bicycle. Use viewBox="0 0 800 600", simple shapes, two clearly visible wheels and a recognizable pelican with a long beak. At most 30 SVG elements and 1800 characters. No Markdown, explanations, comments, scripts, animation, CSS or external resources.

Claude Opus 5.5

Unavailable in this round

DeepSeek-V4-Flash

Popularity compared

How often the models are searched for, used and mentioned, on a scale from 0 to 100.

Both are about as popular: Claude Opus 5.5 68, DeepSeek-V4-Flash 64 out of 100.

Over time

Weekly values from October 18, 2026 to November 7, 2026

Claude Opus 5.5DeepSeek-V4-Flash

All data side by side

The better value is bold. For the overall index only when the gap is clear.

Metric	Claude Opus 5.5	DeepSeek-V4-Flash
Intelligence
Overall indexpoints, 100 = reference group average, higher is better	126.1	n/a
Rank	Rank 1 of 92	not ranked yet
Price per 1M tokens
Inputwhat you send	$4	$0.14
Outputwhat the model writes	$20	$0.28
Cost per task (own tests)average of 2 original-protocol tasks both models passed (SVG short test not included)	$0.12	$0.002
Speed
Tokens per second	106	123
Popularity
Popularitysearch, usage and mentions, 0 to 100	68Rank 8 of 785	64Rank 17 of 785
Technical
Context windowhow much text the model reads at once	1 M tokens≈ 1,500 A4 pages	1 M tokens≈ 1,500 A4 pages
Knowledge cutoff	June 2026	n/a
Released	Sep 22, 2026	Apr 24, 2026
Availability	Active	Limited access
Open weights	no	yes

Prices without caching or batch discounts · Page count as a rule of thumb from Artificial Analysis

Is there a better choice?

Successor of DeepSeek-V4-FlashDeepSeek-V4.1-Flash

Overall index 99.7, rank 29$0.15 input and $0.60 output per 1M tokens

Opus 5.5 vs. DeepSeek-V4.1-Flash

Shared benchmarks

Single results from the same benchmark version, task and metric. A value is bold only with the same test setup and a clear gap.

A: Claude Opus 5.5B: DeepSeek-V4-Flash

LMArena Code Arena WebDevOverall · higher is betterTest setup not documented as identical1,8101,582LMArenaAs of 10/28/2026

LMArena Text, Style ControlOverall · higher is better1,5091,439LMArenaAs of 10/28/2026

LMArena Code Arena WebDevHTML development · higher is betterTest setup not documented as identical1,7531,558LMArenaAs of 10/28/2026

LMArena Text, Style ControlBusiness, management and finance · higher is better1,4951,435LMArenaAs of 10/28/2026

LMArena Code Arena WebDevReact development · higher is betterTest setup not documented as identical1,8601,585LMArenaAs of 10/28/2026

LMArena Text, Style ControlChinese · higher is better1,5741,480LMArenaAs of 10/28/2026

LMArena Code Arena WebDevWeb development · higher is betterTest setup not documented as identical1,8101,582LMArenaAs of 10/28/2026

LMArena Text, Style ControlCoding · higher is better1,5511,480LMArenaAs of 10/28/2026

LMArena Text, Style ControlCreative writing · higher is better1,5201,410LMArenaAs of 10/28/2026

LMArena Text, Style ControlEnglish · higher is better1,5161,450LMArenaAs of 10/28/2026

Show 21 more benchmarks

LMArena Text, Style ControlEntertainment, sports and media · higher is better1,5011,407LMArenaAs of 10/28/2026

LMArena Text, Style ControlExcluding ties · higher is better1,5301,436LMArenaAs of 10/28/2026

LMArena Text, Style ControlExpert prompts · higher is better1,5381,467LMArenaAs of 10/28/2026

LMArena Text, Style ControlFrench prompts · higher is better1,4951,458LMArenaAs of 10/28/2026

LMArena Text, Style ControlGerman prompts · higher is better1,4921,434LMArenaAs of 10/28/2026

LMArena Text, Style ControlHard prompts · higher is better1,5351,458LMArenaAs of 10/28/2026

LMArena Text, Style ControlHard prompts, English · higher is better1,5381,465LMArenaAs of 10/28/2026

LMArena Text, Style ControlInstruction following · higher is better1,5221,434LMArenaAs of 10/28/2026

LMArena Text, Style ControlJapanese prompts · higher is better1,5351,425LMArenaAs of 10/28/2026

LMArena Text, Style ControlLegal and government · higher is better1,5001,458LMArenaAs of 10/28/2026

LMArena Text, Style ControlLife, physical and social science · higher is better1,5151,459LMArenaAs of 10/28/2026

LMArena Text, Style ControlLonger queries · higher is better1,5251,448LMArenaAs of 10/28/2026

LMArena Text, Style ControlMath · higher is better1,5121,442LMArenaAs of 10/28/2026

LMArena Text, Style ControlMathematical professions · higher is better1,5191,445LMArenaAs of 10/28/2026

LMArena Text, Style ControlMedicine and healthcare · higher is better1,5121,460LMArenaAs of 10/28/2026

LMArena Text, Style ControlMulti-turn · higher is better1,4991,447LMArenaAs of 10/28/2026

LMArena Text, Style ControlNon-English · higher is better1,4971,423LMArenaAs of 10/28/2026

LMArena Text, Style ControlRussian prompts · higher is better1,5111,436LMArenaAs of 10/28/2026

LMArena Text, Style ControlSoftware and IT services · higher is better1,5381,473LMArenaAs of 10/28/2026

LMArena Text, Style ControlSpanish prompts · higher is better1,4881,430LMArenaAs of 10/28/2026

LMArena Text, Style ControlWriting, literature and language · higher is better1,5191,422LMArenaAs of 10/28/2026

More comparisons

Compare Claude Opus 5.5 and DeepSeek-V4-Flash with the models people compare them with most often.

Claude Opus 5.5vs.DeepSeek-V4-Flash

Choose Claude Opus 5.5 for

Choose DeepSeek-V4-Flash for

Where is the difference?

Which model for which task?

See for yourself: same task, one attempt

Pelican on a bicycle

SVG short test

Claude Opus 5.5

DeepSeek-V4-Flash

Popularity compared

Over time

All data side by side

Is there a better choice?

Shared benchmarks

More comparisons

Compare another matchup

Predecessor and successor

The most popular comparisons