# Claude Fable 5.1 vs Claude Haiku 4.5

Claude Fable 5.1 is one of Anthropic's newest models and Claude Haiku 4.5 an earlier one, so this is also what moving up costs or saves. Claude Haiku 4.5 is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Claude Fable 5.1 costs 10 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-fable-5-1-vs-claude-haiku-4-5
- Makers: Claude Fable 5.1 from Anthropic, Claude Haiku 4.5 from Anthropic

## Price per million tokens, in US dollars

| | Claude Fable 5.1 | Claude Haiku 4.5 |
| --- | --: | --: |
| Input | $10 | $1 |
| Cached input | $0.25 | $0.10 |
| Cache write | $12.50 | $1.25 |
| Output | $50 | $5 |
| Blend, 3 read for each 1 written | $20 | $2 |
| Batch input | $5 | $0.50 |
| Batch output | $25 | $2.50 |
| Context window, tokens | 1M | 200K |
| Capability score (Epoch Capabilities Index; GPT-5 is 150) | 165 | 142 |
| Longest answer, tokens | 128K | 64K |

## 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 Fable 5.1 | Claude Haiku 4.5 |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $84.00 | $8.40 |
| A hard question, with thinking | 300, 1,400, 100 | $219 | $21.90 |
| A long report, summarised | 60,000, 2,000, 20 | $420 | $42.00 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $1,629 | $220 |
| A support bot's reply | 4,000, 300, 2,000 | $2,130 | $222 |
| Sort a message into a category | 250, 5, 50,000 | $4,125 | $413 |
| Read an invoice into fields | 1,500, 250, 1,000 | $825 | $82.50 |
| Review a pull request | 25,000, 4,500, 50 | $713 | $71.25 |

## Questions

### Which is cheaper, Claude Fable 5.1 or Claude Haiku 4.5?

Claude Haiku 4.5 is cheaper: $1 per million tokens read and $5 per million written, against $10 and $50 on Claude Fable 5.1. On a mix of 3 tokens read for each 1 written, Claude Fable 5.1 costs 10 times as much.

### Which is better, Claude Fable 5.1 or Claude Haiku 4.5?

On the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks, Claude Fable 5.1 scores 165 and Claude Haiku 4.5 142, above the top of the range of doubt around Claude Haiku 4.5'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 Fable 5.1 and Claude Haiku 4.5?

At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $2,130 a month on Claude Fable 5.1 and $222 on Claude Haiku 4.5: Claude Fable 5.1 costs 9.6 times as much for this job.

### What does an AI agent task cost on Claude Fable 5.1 and Claude Haiku 4.5?

One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs $5.43 on Claude Fable 5.1 and 73 cents on Claude Haiku 4.5. At 10 tasks a day that is $1,629 and $220 a month.

### Which has the larger context window, Claude Fable 5.1 or Claude Haiku 4.5?

Claude Fable 5.1, with 1M tokens against 200K on Claude Haiku 4.5. 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 Claude Fable 5.1 and Claude Haiku 4.5?

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 Haiku 4.5 to Claude Fable 5.1?

No, it costs more per token: Claude Fable 5.1 charges $10 per million tokens read and $50 written, against $1 and $5 on Claude Haiku 4.5, 10 times as much for the same tokens. It pays off only if better answers save more than that, for example in fewer retries.

### Can I pay less on Claude Fable 5.1 and Claude Haiku 4.5 for work that can wait?

Yes, on both. With a batch, where you collect the answers later instead of at once, Claude Fable 5.1 costs $5 per million tokens read and $25 written, and Claude Haiku 4.5 $0.50 and $2.50.

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