# Claude Sonnet 5.5 vs Qwen3.8-Flash

Qwen3.8-Flash is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Claude Sonnet 5.5 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/claude-sonnet-5-5-vs-qwen3-8-flash
- Makers: Claude Sonnet 5.5 from Anthropic, Qwen3.8-Flash from Alibaba

## Price per million tokens, in US dollars

| | Claude Sonnet 5.5 | Qwen3.8-Flash |
| --- | --: | --: |
| Input | $2 | $0.15 |
| Cached input | $0.10 | $0.016 |
| Cache write | $2.50 | not listed |
| Output | $10 | $0.47 |
| Blend, 3 read for each 1 written | $4 | $0.23 |
| Batch input | $1 | not listed |
| Batch output | $5 | not listed |
| Context window, tokens | 1M | not listed |
| Capability score (Epoch Capabilities Index; GPT-5 is 150) | 164 | not listed |
| Longest answer, tokens | 128K | not listed |

Price change, Claude Sonnet 5.5: Cached input went from $0.20 to $0.10 per million tokens. The price of a cache write did not change.

## 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:

- Claude Sonnet 5.5: about 2,100 to 3,600 tokens. 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.
- 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 | Claude Sonnet 5.5 | 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 | $364 | $30.34 |
| A support bot's reply | 4,000, 300, 2,000 | $432 | $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, Claude Sonnet 5.5 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 Claude Sonnet 5.5. On a mix of 3 tokens read for each 1 written, Claude Sonnet 5.5 costs 17 times as much.

### Which is better, Claude Sonnet 5.5 or Qwen3.8-Flash?

Claude Sonnet 5.5 scores 164 on the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks (GPT-5 is 150). Qwen3.8-Flash has no independent score yet, so the only fair test is to run the same 10 tasks on both.

### What does a support bot cost a month on Claude Sonnet 5.5 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 $432 a month on Claude Sonnet 5.5 and $28.38 on Qwen3.8-Flash: Claude Sonnet 5.5 costs 15 times as much for this job.

### What does an AI agent task cost on Claude Sonnet 5.5 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 $1.21 on Claude Sonnet 5.5 and 10 cents on Qwen3.8-Flash. At 10 tasks a day that is $364 and $30.34 a month.

### Does the same text take the same number of tokens on Claude Sonnet 5.5 and Qwen3.8-Flash?

No. Our lesson "How AI writes", 1,700 words long, is about 2,100 to 3,600 tokens on Claude Sonnet 5.5 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 Claude Sonnet 5.5 and Qwen3.8-Flash for work that can wait?

On Claude Sonnet 5.5 only: with a batch, where you collect the answers later, it costs $1 per million tokens read and $5 written. Alibaba's price page lists no batch price for Qwen3.8-Flash.

## Sources

- [Anthropic: API prices](https://platform.claude.com/docs/en/about-claude/pricing)
- [Alibaba: API prices](https://www.qwencloud.com/pricing/api)
- [Epoch Capabilities Index, by Epoch AI (CC BY 4.0)](https://epoch.ai/benchmarks/eci)

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