# Claude Sonnet 5 vs Claude Sonnet 5.5

Claude Sonnet 5.5 is one of Anthropic's newest models and Claude Sonnet 5 an earlier one, so this is also what moving up costs or saves. Claude Sonnet 5 and Claude Sonnet 5.5 charge the same per token: $2 per million tokens read and $10 per million written. The bill can still differ, because the same text can be a different number of tokens on each. Below are both price lists, 8 everyday jobs priced on each, and the count for one text.

- Page, with a calculator for your own job: https://tecyfy.com/prices/compare/claude-sonnet-5-vs-claude-sonnet-5-5
- Makers: Claude Sonnet 5 from Anthropic, Claude Sonnet 5.5 from Anthropic

## Price per million tokens, in US dollars

| | Claude Sonnet 5 | Claude Sonnet 5.5 |
| --- | --: | --: |
| Input | $2 | $2 |
| Cached input | $0.20 | $0.10 |
| Cache write | $2.50 | $2.50 |
| Output | $10 | $10 |
| Blend, 3 read for each 1 written | $4 | $4 |
| Batch input | $1 | $1 |
| Batch output | $5 | $5 |
| Context window, tokens | 1M | 1M |
| Capability score (Epoch Capabilities Index; GPT-5 is 150) | 156 | 164 |
| Longest answer, tokens | 128K | 128K |

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.

## 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 | Claude Sonnet 5.5 |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $16.80 | $16.80 |
| A hard question, with thinking | 300, 1,400, 100 | $43.80 | $43.80 |
| A long report, summarised | 60,000, 2,000, 20 | $84.00 | $84.00 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $439 | $364 |
| A support bot's reply | 4,000, 300, 2,000 | $444 | $432 |
| Sort a message into a category | 250, 5, 50,000 | $825 | $825 |
| Read an invoice into fields | 1,500, 250, 1,000 | $165 | $165 |
| Review a pull request | 25,000, 4,500, 50 | $143 | $143 |

## Questions

### Which is cheaper, Claude Sonnet 5 or Claude Sonnet 5.5?

Per token, neither: both charge $2 per million tokens read and $10 per million written. The same text can still be a different number of tokens on each, so the bills can differ.

### Which is better, Claude Sonnet 5 or Claude Sonnet 5.5?

On the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks, Claude Sonnet 5.5 scores 164 and Claude Sonnet 5 156, above the top of the range of doubt around Claude Sonnet 5'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 Sonnet 5 and Claude Sonnet 5.5?

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 Claude Sonnet 5 and $432 on Claude Sonnet 5.5: Claude Sonnet 5 costs 1 times as much for this job.

### What does an AI agent task cost on Claude Sonnet 5 and Claude Sonnet 5.5?

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 Claude Sonnet 5 and $1.21 on Claude Sonnet 5.5. At 10 tasks a day that is $439 and $364 a month.

### Which has the larger context window, Claude Sonnet 5 or Claude Sonnet 5.5?

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 Sonnet 5 and Claude Sonnet 5.5?

Yes, both are counted the same way: our lesson "How AI writes", 1,700 words long, is about 2,100 to 3,600 tokens on each.

### Is it cheaper to move from Claude Sonnet 5 to Claude Sonnet 5.5?

Per token it costs the same: $2 per million tokens read and $10 written on both. The newer model may still use a different number of tokens for the same work.

### Can I pay less on Claude Sonnet 5 and Claude Sonnet 5.5 for work that can wait?

Yes, on both. With a batch, where you collect the answers later instead of at once, Claude Sonnet 5 costs $1 per million tokens read and $5 written, and Claude Sonnet 5.5 $1 and $5.

## Sources

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

## Other comparisons

- [Claude Mythos 5.1 vs Claude Sonnet 5.5](https://tecyfy.com/prices/compare/claude-mythos-5-1-vs-claude-sonnet-5-5.md)
- [Claude Fable 5 vs Claude Sonnet 5.5](https://tecyfy.com/prices/compare/claude-fable-5-vs-claude-sonnet-5-5.md)
- [Claude Mythos 5 vs Claude Sonnet 5.5](https://tecyfy.com/prices/compare/claude-mythos-5-vs-claude-sonnet-5-5.md)
- [Claude Opus 5 vs Claude Sonnet 5.5](https://tecyfy.com/prices/compare/claude-opus-5-vs-claude-sonnet-5-5.md)
- [Claude Opus 4.8 vs Claude Sonnet 5.5](https://tecyfy.com/prices/compare/claude-opus-4-8-vs-claude-sonnet-5-5.md)
- [Claude Opus 4.7 vs Claude Sonnet 5.5](https://tecyfy.com/prices/compare/claude-opus-4-7-vs-claude-sonnet-5-5.md)