DeepSeek V4.1 Flash vs Claude Opus 5.5: Price & Benchmarks

22x Cheaper, 19 Points Behind: Comparing DeepSeek V4.1 Flash and Claude Opus 5.5

DeepSeek V4.1 Flash costs about 22x less per task than Claude Opus 5.5 and runs nearly twice as fast, but Claude Opus 5.5 leads on overall intelligence, scoring 58 to 39 on the Artificial Analysis Intelligence Index. Which one to pick comes down to whether your workload is limited by budget and throughput or by how often the model gets the hard task right on the first try. DeepSeek V4.1 Flash is an open-weight, MIT-licensed 552B MoE model released September 10, 2026, with a 1017 checkpoint shipped on October 17, 2026. Claude Opus 5.5 is Anthropic's proprietary flagship, launched September 22, 2026.

Key Takeaways

• Cost gap: Artificial Analysis measures $0.27 per Intelligence Index task for DeepSeek V4.1 Flash (Max) against $5.98 for Claude Opus 5.5 (Max).
• Capability gap: Claude Opus 5.5 scores 58 on the same index, 19 points above DeepSeek V4.1 Flash's 39.
• Speed: DeepSeek V4.1 Flash outputs 176 tokens/s versus 97 for Opus 5.5 at max effort.
• Token pricing: $0.15/$0.60 per million tokens off-peak for DeepSeek, versus $4/$20 for Opus 5.5.
• Openness: DeepSeek V4.1 Flash ships open weights under MIT. Opus 5.5 is closed.
• Benchmark caveat: DeepSeek's headline "beats Opus" claims compare against Claude Opus 5, not Opus 5.5.

DeepSeek V4.1 Flash vs Claude Opus 5.5 at a Glance

Dimension	DeepSeek V4.1 Flash	Claude Opus 5.5
Release	Sep 10, 2026 (1017 checkpoint Oct 17)	Sep 22, 2026
License	Open weights, MIT	Proprietary
Architecture	552B MoE, 8B active on prefill / 16B on decode, plus 196B Engram memory	Not published
Context window	1M tokens	1M tokens
Input / output modality	Text + image / text	Text + image / text
API price (input / output per 1M)	$0.15 / $0.60 off-peak; $0.30 / $1.20 peak	$4 / $20
Cache read per 1M	$0.003 off-peak; $0.006 peak	Not yet confirmed in primary sources
AA Intelligence Index (max effort)	39	58
AA cost per index task (max)	$0.27	$5.98
AA output speed (max)	176 tokens/s	97 tokens/s
ARC-AGI-2	72.9% (ARC Prize verified, per community reports)	Not yet confirmed

Third-party numbers come from the Artificial Analysis release comparison. DeepSeek's architecture and pricing come from its official launch post and the Hugging Face model card.

Benchmarks: Where Each Model Leads

The most direct head-to-head comes from Artificial Analysis, which ran both models under the same harness. Opus 5.5 leads on every capability index it publishes. Finance & Accounting scores 61 vs 45, Strategy & Ops 64 vs 52, Legal 63 vs 41, and Healthcare & Medical 61 vs 41. Even Opus 5.5 at low effort (42) edges past DeepSeek V4.1 Flash at max effort (39).

Coding tells a similar story on independent tests. On Artificial Analysis's FrontierCode 1.1 board, which grades whether AI-written code meets open-source maintainer merge standards, Claude Opus 5.5 ranked first at 52.2% while DeepSeek V4.1 Flash scored 44%, according to a summary of the release. That same report put Opus 5.5's cost at $10.15 per task.

Source: @0xLogicrw

Terminal work is the clearest gap. Anthropic's Opus 5.5 launch reported 66.4% on Terminal-Bench 4.0, up from 57.9% on Opus 5, per a launch recap. DeepSeek's official figure for the 1017 checkpoint is 42.3%, up from 31.2% on the original V4.1 Flash.

DeepSeek's own wins are real but scoped. The 1017 checkpoint reports 77.0 on DeepSWE v1.1, 60.5 on Automation-Bench and 35.4 on Agents' Last Exam, all ahead of the Claude Opus 5 figures DeepSeek chose to compare against (74.0, 50.3 and 28.6), as listed in a breakdown of the release table. None of those official tables include Opus 5.5.

Source: @kimmonismus

DeepSeek V4.1 Flash beats Claude Opus 5 on several agent benchmarks, but the published data does not show it beating Claude Opus 5.5.

Community impressions, which are not controlled measurements, run in both directions. One heavy user claims DeepSeek tops Opus 5.5 in LiveBench's agentic coding category; that is unverified here. A 10-round YouTube comparison built on Artificial Analysis, Vals AI, Epoch AI and Mercor data gave Opus 5.5 the brainpower, coding, math, real-work and honesty rounds. DeepSeek took price, speed and openness. Agent Arena reports the top five agent models now confirm 94% of tasks done, led by Claude Opus 5.5, while DeepSeek V4.1 Flash matches the older Claude Fable 5 at 96% lower cost per task.

Pricing and Cost per Task

List prices understate nothing here: the gap is large at every layer. Off-peak, Opus 5.5 output costs about 33x more per token ($20 vs $0.60); at DeepSeek's peak rate the multiple drops to about 17x ($20 vs $1.20). DeepSeek's peak window runs Monday to Friday, 01:00–04:00 and 06:00–10:00 UTC, as VentureBeat documented.

Cost per finished task is the fairer metric, because DeepSeek V4.1 Flash is verbose. Artificial Analysis flags it as "very verbose," with about 250M output tokens across its index run. Even so, per-task cost lands at $0.27 versus $5.98 for Opus 5.5 at max effort, roughly 22x. At low effort, Opus 5.5 drops to $0.55 per task, still about 2x the DeepSeek max-effort figure.

Effort setting	Intelligence Index	Cost per task	Output speed
Opus 5.5 Max	58	$5.98	97 t/s
Opus 5.5 High	54	$1.82	83 t/s
Opus 5.5 Low	42	$0.55	84 t/s
DeepSeek V4.1 Flash Max	39	$0.27	176 t/s
DeepSeek V4.1 Flash Non-reasoning	25	$0.15	163 t/s

Source: Artificial Analysis comparison page. Anthropic says Opus 5.5 typical workloads cost 40% less than on Opus 5, per the launch recap above.

Context, Speed and Deployment

Both models offer a 1M-token context window. DeepSeek's Causal Encoder-Decoder (CED) design and its compressed KV cache, which DeepSeek puts at 890 bytes per token, aim specifically at making long-context agent loops cheap. Its DSpark speculative decoding and Engram conditional memory are what let community builders fit the 510 GB checkpoint onto two to four DGX Sparks. Our first look at DeepSeek V4.1 Flash covers that architecture in more depth.

Latency differs sharply at max effort. Artificial Analysis records 1.23 seconds to first token for DeepSeek and 728.27 seconds for Opus 5.5 (Max), which reflects Opus's long reasoning phase. Opus 5.5 at low effort drops to 6.69 seconds. Real-world DeepSeek API speed varies; community reports range from about 150 to over 300 tokens/s depending on load.

Access routes:

Route	DeepSeek V4.1 Flash	Claude Opus 5.5
Vendor app / web	DeepSeek Web and App	Anthropic Claude apps
Vendor API	DeepSeek API, model name deepseek-flash	Anthropic API
kie.ai API	DeepSeek-V4.1-Flash on kie.ai	Claude Opus 5.5 on kie.ai
Self-hosting	Yes, MIT open weights	No

kie.ai offers DeepSeek V4.1 Flash via API, which puts it next to Opus 5.5 under one account for teams that want to route between them.

Which One Should You Use?

Choose DeepSeek V4.1 Flash if:

• You run high-volume agent loops where 22x lower cost per task outweighs a 19-point index gap.
• You need open weights for on-prem, data-residency or fine-tuning reasons.
• Throughput and fast first tokens matter more than first-attempt accuracy on the hardest tasks.

Choose Claude Opus 5.5 if:

• Your tasks resemble Terminal-Bench or FrontierCode, where Opus 5.5 leads by 24 and 8 points respectively.
• You work in legal, finance or healthcare domains, where Artificial Analysis shows 16 to 22 point gaps.
• A failed attempt costs more than the extra $5.71 per task.

A common pattern in community reports is a hybrid: Opus 5.5 for planning and review, DeepSeek V4.1 Flash for bulk execution. For context on another budget challenger against the same flagship, see our Nemotron 3.5 Super VL vs Claude Opus 5.5 comparison.

Frequently Asked Questions

Is DeepSeek V4.1 Flash better than Claude Opus 5.5?

No, not overall. Claude Opus 5.5 scores 58 on the Artificial Analysis Intelligence Index versus 39 for DeepSeek V4.1 Flash. DeepSeek wins on cost per task ($0.27 vs $5.98) and output speed (176 vs 97 tokens/s).

Is DeepSeek V4.1 Flash cheaper than Claude Opus 5.5?

Yes, by a wide margin. DeepSeek V4.1 Flash costs $0.15 input and $0.60 output per million tokens off-peak, or $0.30/$1.20 at peak. Claude Opus 5.5 costs $4 input and $20 output.

Which is better for coding, DeepSeek V4.1 Flash or Claude Opus 5.5?

Claude Opus 5.5 leads the independent coding data: 52.2% vs 44% on FrontierCode 1.1, and 66.4% vs 42.3% on Terminal-Bench 4.0. DeepSeek V4.1 Flash is the cost-efficient pick for high-volume agent loops.

Do DeepSeek V4.1 Flash and Claude Opus 5.5 have the same context window?

Yes. Both support 1M tokens of context and accept text and image input with text output.

Can I run Claude Opus 5.5 locally like DeepSeek V4.1 Flash?

No. Claude Opus 5.5 is proprietary and API-only. DeepSeek V4.1 Flash ships MIT-licensed open weights, and community builds run it on two to four DGX Sparks.

Is DeepSeek V4.1 Flash faster than Claude Opus 5.5?

Yes. Artificial Analysis measures 176 output tokens/s for DeepSeek V4.1 Flash versus 97 for Opus 5.5 at max effort, with time to first token of about 1.23 seconds versus about 728 seconds.

What to Watch Next

Three signals will move this comparison. First, independent Artificial Analysis and FrontierCode scores for the 1017 checkpoint, since DeepSeek's own tables only compare against Opus 5. Second, DeepSeek V4.1 Pro, which DeepSeek has said will follow the Flash release and could narrow the capability gap. Third, whether ARC Prize publishes an Opus 5.5 result to set against DeepSeek's 72.9% on ARC-AGI-2.

Try related models on Kie.ai: DeepSeek-V4.1-Flash, Claude Opus 5.5 and Gemini 4 Argon.