Claude Opus 5.5 vs DeepSeek V4.1 Flash
DeepSeek V4.1 Flash is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Claude Opus 5.5 costs 15 times as much. Below are both price lists, what 8 everyday jobs cost a month on each, and how many tokens the same text takes on each, which can change the answer.
- For the same tokens
- DeepSeek V4.1 Flash is cheaper; Claude Opus 5.5 costs 15 times as much
- Cheaper to read
- DeepSeek V4.1 Flash, $0.30 against $4
- Cheaper to write
- DeepSeek V4.1 Flash, $1.20 against $20
- Scores higher
- Claude Opus 5.5, 167 against 156
- Larger window
- The same, 1M tokens each
Price per million tokens, side by side
In US dollars, as each maker prints them. The better figure in each row is green.
| Claude Opus 5.5Anthropic | DeepSeek V4.1 FlashDeepSeek | |
|---|---|---|
| InputTokens the model reads | $4 | $0.30 |
| Cached inputRead again from the cache | $0.20 | $0.006 |
| Cache writePutting text in the cache | $5 | Not listed |
| OutputTokens it writes, thinking included | $20 | $1.20 |
| Blend 3:13 tokens read for each 1 written | $8 | $0.525 |
| Batch inputAnswers collected later | $2 | Not listed |
| Batch output | $10 | Not listed |
| Context windowTokens it holds at once | 1M | 1M |
| Capability scoreEpoch Capabilities Index; GPT-5 is 150 | 167 | 156 |
| Longest answerTokens it writes in 1 reply | 128K | Not listed |
Read before you choose
- DeepSeek V4.1 Flash: The peak-hours price. Off-peak hours are half. Peak is 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays.
The same text, counted by each maker
A price per token means little until you know how many tokens your text is. Here is our lesson How AI writes, about 1,700 words of English, counted the way each maker counts it, and what it costs to send it once.
Claude Opus 5.5
about 2,100 to 3,600 tokens
Sent once: 0.82 cents to 1.4 cents at $4 per million
Anthropic does not publish its tokenizer. It says Claude 4.7 and later produce about 30 percent more tokens for the same text than earlier models, and an independent test counted TypeScript at 1.73 times OpenAI's figure. The range runs from OpenAI's count to 1.75 times it.
DeepSeek V4.1 Flash
2,063 tokens
Sent once: 0.062 cents at $0.30 per million
Counted with the tokenizer DeepSeek publishes with V4-Pro and V4.1 Flash, the same models its API serves.
What 8 everyday jobs cost a month on each
Each job at its usual number of runs a day, for 30 days, at the standard price. The cheaper of the 2 is green; open any job in the calculator to change it. Sizes are in tokens, and Claude Opus 5.5 can need up to 1.7 times as many as DeepSeek V4.1 Flash for the same words, so its bill for the same work can be up to that much higher.
| Job | Claude Opus 5.5 | DeepSeek V4.1 Flash | Difference |
|---|---|---|---|
| A chat question300 in, 500 out, 100 a day | $33.601.1 cents a run | $2.070.069 cents a run | 16 times |
| A hard question, with thinking300 in, 1,400 out, 100 a day | $87.602.9 cents a run | $5.310.18 cents a run | 16 times |
| A long report, summarised60,000 in, 2,000 out, 20 a day | $16828 cents a run | $12.242 cents a run | 14 times |
| A 40-turn agent task2,800,000 in, 40,000 out, 10 a day | $727$2.42 a run | $44.1415 cents a run | 16 times |
| A support bot's reply4,000 in, 300 out, 2,000 a day | $8641.4 cents a run | $58.320.097 cents a run | 15 times |
| Sort a message into a category250 in, 5 out, 50,000 a day | $1,6500.11 cents a run | $1220.0081 cents a run | 14 times |
| Read an invoice into fields1,500 in, 250 out, 1,000 a day | $3301.1 cents a run | $22.500.075 cents a run | 15 times |
| Review a pull request25,000 in, 4,500 out, 50 a day | $28519 cents a run | $19.351.3 cents a run | 15 times |
Your own job on both
Start from a job, then set its size, how often it runs and whether the answers can wait. Both bills follow every change.
A short question and a few paragraphs back.
about 230 words
Instructions or documents the model has read before cost far less the second time.
about 380 words
A month of this job
- Claude Opus 5.5$33.60
1.1 cents a run
- DeepSeek V4.1 Flash$2.07
0.069 cents a run
DeepSeek V4.1 Flash saves $31.53 a month; Claude Opus 5.5 costs 16 times as much.
This job on every modelWhy the price per token is only the start
Every maker prints 2 main prices: one for the tokens a model reads (input) and one for the tokens it writes (output). On most current models writing costs 3 to 5 times as much as reading, so which model is cheaper can depend on the job. A job that reads a long document and writes a line pays mostly the input price; a chat that writes paragraphs pays mostly the output price. That is why each comparison prices 8 jobs and not one figure.
The same text is not the same number of tokens on every model. Each maker cuts text its own way, and Anthropic says its models from Claude 4.7 on produce about 30 percent more tokens for the same text than earlier ones. A model with the lower price per token can still send the larger bill, so each comparison counts one of our lessons the way both makers count it.
Discounts change the order too. Work that can wait costs half on a batch at the makers that offer one, and text read again from a cache costs a quarter of the input price or less on every current model here. The price table on each comparison shows who offers what.
Thinking is billed as output, and models differ in how much they think and how long they answer. A price list cannot show that. Before you switch, run the same 10 tasks on both models and compare the bills.
Questions
- Which is cheaper, Claude Opus 5.5 or DeepSeek V4.1 Flash?
- DeepSeek V4.1 Flash is cheaper: $0.30 per million tokens read and $1.20 per million written, against $4 and $20 on Claude Opus 5.5. On a mix of 3 tokens read for each 1 written, Claude Opus 5.5 costs 15 times as much.
- Which is better, Claude Opus 5.5 or DeepSeek V4.1 Flash?
- On the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks, Claude Opus 5.5 scores 167 and DeepSeek V4.1 Flash 156, above the top of the range of doubt around DeepSeek V4.1 Flash's score (GPT-5 is 150). One score is an average; test both on your own work before you switch.
- What does a support bot cost a month on Claude Opus 5.5 and DeepSeek V4.1 Flash?
- At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $864 a month on Claude Opus 5.5 and $58.32 on DeepSeek V4.1 Flash: Claude Opus 5.5 costs 15 times as much for this job.
- What does an AI agent task cost on Claude Opus 5.5 and DeepSeek V4.1 Flash?
- One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs $2.42 on Claude Opus 5.5 and 15 cents on DeepSeek V4.1 Flash. At 10 tasks a day that is $727 and $44.14 a month.
- Which has the larger context window, Claude Opus 5.5 or DeepSeek V4.1 Flash?
- Neither: both hold 1M tokens at once, about 1,500 pages of English text.
- Does the same text take the same number of tokens on Claude Opus 5.5 and DeepSeek V4.1 Flash?
- No. Our lesson "How AI writes", 1,700 words long, is about 2,100 to 3,600 tokens on Claude Opus 5.5 and 2,063 on DeepSeek V4.1 Flash. Each maker cuts text its own way, and every extra token is paid for at the model's price.
- Can I pay less on Claude Opus 5.5 and DeepSeek V4.1 Flash for work that can wait?
- On Claude Opus 5.5 only: with a batch, where you collect the answers later, it costs $2 per million tokens read and $10 written. DeepSeek's price page lists no batch price for DeepSeek V4.1 Flash.
Sources