Claude Opus 5.5
- Input / 1M tokens
- $4.00
- Output / 1M tokens
- $20.00
API models · Side by side
Claude Opus 5.5 vs DeepSeek V4.1 Flash
Claude Opus 5.5 is a premium model, and DeepSeek V4.1 Flash is one of the cheapest capable models available. The price gap is enormous, so the real question is how much checking and correcting each one needs.
DeepSeek V4.1 Flash
- Input / 1M tokens
- $0.15
- Output / 1M tokens
- $0.60
The short answer
Opus charges $4 per million input tokens and $20 per million output tokens. DeepSeek charges $0.15 and $0.60 off-peak ($0.30 and $1.20 at weekday peak times), roughly 13 to 33 times cheaper. Opus reads files directly; DeepSeek takes text and images only. DeepSeek can write longer replies: about 393,000 tokens vs 128,000.
Compare the details
Compare context, supported inputs and usage costs. Highlighted rows show a difference.
| Feature | Claude Opus 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Input formats | file, image, text | image, text |
| Output formats | text | text |
| Context / position limit | 1,000,000 | 1,048,576 |
| Maximum output tokens | 128,000 | 393,216 |
| Developer features | Reasoning output, Completion limit, Output limit, Reasoning controls, Thinking effort, Response format, Stop sequences, Structured output, Tool selection, Tool calling, Response length | frequency penalty, Reasoning output, logit bias, logprobs, Output limit, min p, presence penalty, Reasoning controls, Thinking effort, repetition penalty, Response format, Seed, Stop sequences, Structured output, Temperature, Tool selection, Tool calling, top k, top logprobs, Sampling controls |
| Cached input / 1M tokens | $0.20 | $0.003000 |
| Cache write / 1M tokens | $5.00 | Unknown |
| USD input / 1M tokens | $4.00 | $0.15 |
| USD output / 1M tokens | $20.00 | $0.60 |
| Model identifier | anthropic/claude-opus-5.5 | deepseek/deepseek-v4.1-flash |
API pricing
Prices are in USD per million tokens. Input is what you send; output is what the model generates. Claude and ChatGPT subscriptions are billed separately.
DeepSeek V4.1 Flash: long-prompt rates
- Long-prompt threshold: 0 prompt tokens. Input: $0.15 / 1M. Output: $0.60 / 1M.
- Long-prompt threshold: 0 prompt tokens. Input: $0.15 / 1M. Output: $0.60 / 1M.
- Long-prompt threshold: 0 prompt tokens. Input: $0.30 / 1M. Output: $1.20 / 1M.
- Long-prompt threshold: 0 prompt tokens. Input: $0.15 / 1M. Output: $0.60 / 1M.
- Long-prompt threshold: 0 prompt tokens. Input: $0.30 / 1M. Output: $1.20 / 1M.
- Long-prompt threshold: 0 prompt tokens. Input: $0.15 / 1M. Output: $0.60 / 1M.
Tools, images and additional reasoning can add charges. The examples below cover input and output tokens only.
Compare local modelsWhat those prices mean in practice
Each example uses the same token budget for both models. These are calculations, not measured workloads. Cache discounts, media, tools and extra reasoning are excluded.
| Workload | Claude Opus 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| 1,000 short requestsPer request: 2,000 input + 500 output tokens | $18.00 | $0.60 |
| 100 document summariesPer request: 20,000 input + 1,000 output tokens | $10.00 | $0.36 |
| 10 long-document requestsPer request: 300,000 input + 2,000 output tokens | $12.40 | $0.46 |
Estimate = requests × (input tokens × input price + output tokens × output price) ÷ 1,000,000. Long-prompt rates are applied where the pricing data provides them. Real requests can use different amounts of output.
Beyond the price tag
Compare finished work
For a report, decide which sections and facts it must cover. For code, decide what must change and what must not break. Give both models the same material, then compare how much fixing each result needs. That's the real cost.
Keep the source material
Opus can read your files directly. With DeepSeek, documents are converted first, so make sure the conversion keeps what the task depends on, such as tables, figures and page structure.
Long isn't the same as complete
DeepSeek can write much longer replies, but length doesn't guarantee coverage. Ask for the specific sections you need, and check each one.
Which one should you pick?
Choose DeepSeek V4.1 Flash for high-volume work with clear checks, where the savings are huge. Choose Claude Opus 5.5 for selected difficult tasks where your tests show it saves enough correction time to justify the price.
Common questions
Is Opus automatically more accurate?
No. A higher price doesn't guarantee better answers on every task. Test with your own work.
Can DeepSeek write more in one reply?
Yes, its output limit is higher. But input and output share the context window, and a longer reply isn't automatically a better one.