# DeepSeek V4.1 Flash vs o3

DeepSeek V4.1 Flash is the cheaper of the 2: for the same tokens, 3 read for each 1 written, o3 costs 6.7 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.

- Page, with a calculator for your own job: https://tecyfy.com/prices/compare/deepseek-flash-vs-o3
- Makers: DeepSeek V4.1 Flash from DeepSeek, o3 from OpenAI

## Price per million tokens, in US dollars

| | DeepSeek V4.1 Flash | o3 |
| --- | --: | --: |
| Input | $0.30 | $2 |
| Cached input | $0.006 | $0.50 |
| Cache write | not listed | not listed |
| Output | $1.20 | $8 |
| Blend, 3 read for each 1 written | $0.525 | $3.50 |
| Batch input | not listed | $1 |
| Batch output | not listed | $4 |
| Context window, tokens | 1M | 200K |
| Capability score (Epoch Capabilities Index; GPT-5 is 150) | 156 | 147 |
| Longest answer, tokens | not listed | 100K |

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

Our lesson "How AI writes" (https://tecyfy.com/learn/how-ai-works/how-ai-writes), about 1,700 words of English:

- DeepSeek V4.1 Flash: 2,063 tokens. Counted with the tokenizer DeepSeek publishes with V4-Pro and V4.1 Flash, the same models its API serves.
- o3: about 2,100 tokens. GPT-5.6 is counted with o200k_base, the tokenizer OpenAI publishes for it, so its count is exact. OpenAI has not published the tokenizer of GPT-6, so its count is the same o200k_base figure, marked as about.

## What 8 everyday jobs cost a month on each

Each job at its usual runs a day, for 30 days, at the standard price.

| Job | Tokens in, out, runs a day | DeepSeek V4.1 Flash | o3 |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $2.07 | $13.80 |
| A hard question, with thinking | 300, 1,400, 100 | $5.31 | $35.40 |
| A long report, summarised | 60,000, 2,000, 20 | $12.24 | $81.60 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $44.14 | $642 |
| A support bot's reply | 4,000, 300, 2,000 | $58.32 | $444 |
| Sort a message into a category | 250, 5, 50,000 | $122 | $810 |
| Read an invoice into fields | 1,500, 250, 1,000 | $22.50 | $150 |
| Review a pull request | 25,000, 4,500, 50 | $19.35 | $129 |

## Questions

### Which is cheaper, DeepSeek V4.1 Flash or o3?

DeepSeek V4.1 Flash is cheaper: $0.30 per million tokens read and $1.20 per million written, against $2 and $8 on o3. On a mix of 3 tokens read for each 1 written, o3 costs 6.7 times as much.

### Which is better, DeepSeek V4.1 Flash or o3?

On the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks, DeepSeek V4.1 Flash scores 156 and o3 147, above the top of the range of doubt around o3'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 DeepSeek V4.1 Flash and o3?

At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $58.32 a month on DeepSeek V4.1 Flash and $444 on o3: o3 costs 7.6 times as much for this job.

### What does an AI agent task cost on DeepSeek V4.1 Flash and o3?

One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs 15 cents on DeepSeek V4.1 Flash and $2.14 on o3. At 10 tasks a day that is $44.14 and $642 a month.

### Which has the larger context window, DeepSeek V4.1 Flash or o3?

DeepSeek V4.1 Flash, with 1M tokens against 200K on o3. The window holds your instructions, the files you attach, the conversation so far and the answer, all at once.

### Does the same text take the same number of tokens on DeepSeek V4.1 Flash and o3?

No. Our lesson "How AI writes", 1,700 words long, is 2,063 tokens on DeepSeek V4.1 Flash and about 2,100 on o3. Each maker cuts text its own way, and every extra token is paid for at the model's price.

### Can I pay less on DeepSeek V4.1 Flash and o3 for work that can wait?

On o3 only: with a batch, where you collect the answers later, it costs $1 per million tokens read and $4 written. DeepSeek's price page lists no batch price for DeepSeek V4.1 Flash.

## Sources

- [DeepSeek: API prices](https://api-docs.deepseek.com/quick_start/pricing)
- [OpenAI: API prices](https://developers.openai.com/api/docs/pricing)
- [Epoch Capabilities Index, by Epoch AI (CC BY 4.0)](https://epoch.ai/benchmarks/eci)

## Other comparisons

- [GPT-6 Astra vs o3](https://tecyfy.com/prices/compare/gpt-6-astra-vs-o3.md)
- [GPT-6.1 Sol vs o3](https://tecyfy.com/prices/compare/gpt-6-1-sol-vs-o3.md)
- [GPT-6 Luna vs o3](https://tecyfy.com/prices/compare/gpt-6-luna-vs-o3.md)
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- [Claude Haiku 5.5 vs DeepSeek V4.1 Flash](https://tecyfy.com/prices/compare/claude-haiku-5-5-vs-deepseek-flash.md)
- [DeepSeek V4.1 Flash vs Qwen3.8-Flash](https://tecyfy.com/prices/compare/deepseek-flash-vs-qwen3-8-flash.md)