# Kimi K3.1 Pro vs Qwen3.8-Flash

Qwen3.8-Flash is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Kimi K3.1 Pro costs 17 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/kimi-k3-1-pro-vs-qwen3-8-flash
- Makers: Kimi K3.1 Pro from Moonshot AI, Qwen3.8-Flash from Alibaba

## Price per million tokens, in US dollars

| | Kimi K3.1 Pro | Qwen3.8-Flash |
| --- | --: | --: |
| Input | $2 | $0.15 |
| Cached input | $0.20 | $0.016 |
| Cache write | $2 | not listed |
| Output | $10 | $0.47 |
| Blend, 3 read for each 1 written | $4 | $0.23 |
| Batch input | not listed | not listed |
| Batch output | not listed | not listed |
| Context window, tokens | 1.05M | not listed |
| Capability score (Epoch Capabilities Index; GPT-5 is 150) | not listed | not listed |
| Longest answer, tokens | not listed | not listed |

## 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:

- Kimi K3.1 Pro: about 2,100 tokens. Counted with the tokenizer Moonshot AI publishes with Kimi K3, the model its API serves.
- Qwen3.8-Flash: about 2,100 tokens. Counted with the tokenizer Alibaba publishes with its open Qwen3.8 models. Alibaba does not say its API models use the same one, so the count is 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 | Kimi K3.1 Pro | Qwen3.8-Flash |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $16.80 | 84 cents |
| A hard question, with thinking | 300, 1,400, 100 | $43.80 | $2.11 |
| A long report, summarised | 60,000, 2,000, 20 | $84.00 | $5.96 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $439 | $30.34 |
| A support bot's reply | 4,000, 300, 2,000 | $444 | $28.38 |
| Sort a message into a category | 250, 5, 50,000 | $825 | $59.77 |
| Read an invoice into fields | 1,500, 250, 1,000 | $165 | $10.27 |
| Review a pull request | 25,000, 4,500, 50 | $143 | $8.80 |

## Questions

### Which is cheaper, Kimi K3.1 Pro or Qwen3.8-Flash?

Qwen3.8-Flash is cheaper: $0.15 per million tokens read and $0.47 per million written, against $2 and $10 on Kimi K3.1 Pro. On a mix of 3 tokens read for each 1 written, Kimi K3.1 Pro costs 17 times as much.

### What does a support bot cost a month on Kimi K3.1 Pro and Qwen3.8-Flash?

At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $444 a month on Kimi K3.1 Pro and $28.38 on Qwen3.8-Flash: Kimi K3.1 Pro costs 16 times as much for this job.

### What does an AI agent task cost on Kimi K3.1 Pro and Qwen3.8-Flash?

One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs $1.46 on Kimi K3.1 Pro and 10 cents on Qwen3.8-Flash. At 10 tasks a day that is $439 and $30.34 a month.

### Does the same text take the same number of tokens on Kimi K3.1 Pro and Qwen3.8-Flash?

No. Our lesson "How AI writes", 1,700 words long, is about 2,100 tokens on Kimi K3.1 Pro and about 2,100 on Qwen3.8-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 Kimi K3.1 Pro and Qwen3.8-Flash for work that can wait?

Not with a batch price: neither maker's price page lists one for these models. A cache still lowers the price of text the model reads again.

## Sources

- [Moonshot AI: API prices](https://platform.kimi.ai/docs/pricing/chat)
- [Alibaba: API prices](https://www.qwencloud.com/pricing/api)

## Other comparisons

- [Kimi K3.1 Pro vs Kimi K3.1 Pro Highspeed](https://tecyfy.com/prices/compare/kimi-k3-1-pro-vs-kimi-k3-1-pro-highspeed.md)
- [Kimi K3 vs Kimi K3.1 Pro](https://tecyfy.com/prices/compare/kimi-k3-vs-kimi-k3-1-pro.md)
- [Kimi K2.7 Code vs Kimi K3.1 Pro](https://tecyfy.com/prices/compare/kimi-k2-7-code-vs-kimi-k3-1-pro.md)
- [Kimi K2.7 Code Highspeed vs Kimi K3.1 Pro](https://tecyfy.com/prices/compare/kimi-k2-7-code-highspeed-vs-kimi-k3-1-pro.md)
- [Kimi K2.6 vs Kimi K3.1 Pro](https://tecyfy.com/prices/compare/kimi-k2-6-vs-kimi-k3-1-pro.md)
- [Qwen3.7-Max vs Qwen3.8-Flash](https://tecyfy.com/prices/compare/qwen3-7-max-vs-qwen3-8-flash.md)