Cheaper alternatives to Claude Fable 5.1
Claude Fable 5.1 costs $10 / $50 per 1M input / output tokens and scores 166 on Epoch AI’s Capabilities Index. 6 current models score within its margin of error for less, the cheapest being Claude Haiku 5.5 at 99% less. Prices checked 13 Oct – 6 Nov 2026.
Similar capability, lower price
Highest score first
| Model | Capability | Input / output per 1M | Cheaper by | Customer chat assistant, a month | Compare |
|---|---|---|---|---|---|
 GPT-6.1 TerraOpenAI |
168level, within the margin | $1.00 / $5.00 | 90% | $153 | Compare |
| GPT-6.1 SolOpenAI |
168level, within the margin | $2.00 / $10.00 | 80% | $305 | Compare |
 Claude Opus 5.5Anthropic |
168level, within the margin | $4.00 / $20.00 | 60% | $610 | Compare |
| Claude Sonnet 5.5Anthropic |
167level, within the margin | $2.00 / $10.00 | 80% | $305 | Compare |
 Gemini 4 ArgonGoogle |
166level, within the margin | $2.00 / $10.00 | 80% | $305 | Compare |
| Claude Haiku 5.5Anthropic |
160level, within the margin | $0.10 / $0.50 | 99% | $15.50 | Compare |
A step down, for much less
Highest score first
| Model | Capability | Input / output per 1M | Cheaper by | Customer chat assistant, a month | Compare |
|---|---|---|---|---|---|
| Gemini 3.8 FlashGoogle |
1588 below | $0.75 / $3.75 | 93% | $116 | Compare |
 Qwen3.8 MaxAlibaba |
1588 below | $2.00 / $6.00 | 85% | $320 | Compare |
 Kimi K3Moonshot AI · open weights |
1588 below | $3.00 / $15.00 | 70% | $465 | Compare |
| GPT-6 LunaOpenAI |
1579 below | $0.10 / $0.50 | 99% | $15.50 | Compare |
 Muse Spark 1.3Meta |
1579 below | $1.25 / $4.25 | 90% | $155 | Compare |
 DeepSeek V4.1 FlashDeepSeek |
15610 below | $0.30 / $1.20 | 97% | $39.30 | Compare |
 GLM-5.3Z.ai |
15610 below | $1.40 / $4.40 | 89% | $171 | Compare |
 Grok 4.7xAI |
15511 below | $2.00 / $6.00 | 85% | $245 | Compare |
| Gemini 3.1 ProGoogle |
15511 below | $2.00 / $12.00 | 78% | $350 | Compare |
Other frontier models, not yet scored
| Model | Capability | Input / output per 1M | Cheaper by | Customer chat assistant, a month | Compare |
|---|---|---|---|---|---|
| Kimi K3.1 ProMoonshot AI |
Not scored | $2.00 / $10.00 | 80% | $310 | Compare |
What switching saves on three workloads
Per month, list prices
| Workload | Claude Fable 5.1 | Claude Haiku 5.5 | Claude Opus 5.5 | Gemini 3.8 Flash |
|---|---|---|---|---|
| Customer chat assistant100M in, 20M out, 50% cached | $1,513 | $15.50 | $610 | $116 |
| Document Q&A (RAG)240M in, 12M out, 30% cached | $2,298 | $23.52 | $926 | $176 |
| Coding agent750M in, 8M out, 85% cached | $1,684 | $21.63 | $738 | $162 |
Monthly cost at list prices with no batch discount. Your own numbers: open these models in the cost calculator.
How to choose
- Same quality, smaller bill: Claude Haiku 5.5 scores level with Claude Fable 5.1 and costs 99% less. Test it on your hardest prompts first.
- Stay with Anthropic: Claude Opus 5.5 keeps the same API, tools and data terms at $4 / $20.
- Mix models: send routine requests to a cheaper model and keep Claude Fable 5.1 for the hard ones. How much that saves depends on your traffic, so measure quality on a sample before switching everything.
- Cut the bill without switching: batch processing and prompt caching often save more than changing model. See how to cut your API bill in half.
Questions
What is the cheapest alternative to Claude Fable 5.1 with similar capability?
Claude Haiku 5.5 from Anthropic, at $0.10 / $0.50 per 1M input / output tokens, 99% less than Claude Fable 5.1 at a typical 3:1 mix. On Epoch AI’s Capabilities Index it scores 160 against 166, within the margin of error.
Is GPT-6.1 Terra as good as Claude Fable 5.1?
On general benchmarks, they’re level: Epoch AI’s Capabilities Index gives GPT-6.1 Terra 168 (range 165–173) and Claude Fable 5.1 166 (164–171). Benchmarks don’t cover every task, so run both on a sample of your own work before switching.
How much would I save by switching from Claude Fable 5.1?
For a customer chat assistant (100M input and 20M output tokens a month, half the input cached), Claude Fable 5.1 costs $1,513 a month. Claude Haiku 5.5 costs $15.50, Claude Opus 5.5 $610.
Is there a cheaper Anthropic model than Claude Fable 5.1?
Yes: Claude Opus 5.5 ($4 / $20, capability 168), Claude Sonnet 5.5 ($2 / $10, capability 167), Claude Haiku 5.5 ($0.10 / $0.50, capability 160). Staying with Anthropic keeps your prompts, tools and billing the same.
Why isn’t every cheaper model listed?
We list current models that cost less than Claude Fable 5.1 at a 3:1 input-to-output mix and either score within about 12 points of it on Epoch AI’s index or are in the same tier without a score yet. Much weaker models are cheaper still but rarely a like-for-like swap.
Capability: Epoch Capabilities Index by Epoch AI, CC BY 4.0, read 4 Nov 2026. Prices from each provider’s own page, linked on every model page.