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K = 0.731
All model prices

Claude Fable 5.1 vs Claude Sonnet 5.5 API pricing

For a chat message (1K input, 500 output), Claude Sonnet 5.5 costs $0.007 per request and Claude Fable 5.1 costs $0.035, so Claude Sonnet 5.5 is about 5× cheaper.

On the overall leaderboard Claude Fable 5.1 ranks #4 and Claude Sonnet 5.5 ranks #8.

Prices are the standard pay-as-you-go prices in OpenRouter's public model list, with input at the cache-miss price. Models OpenRouter does not list use the vendor's official price; those listed in CNY are converted to USD at this round's exchange rate.

Work it out for your own usageSee the model leaderboard

Prices and rankings

USD per million tokensClaude Fable 5.1Claude Sonnet 5.5
Input$10$2
Output$50$10
Cached input$0.25$0.1
ProviderAnthropicAnthropic
Release date2026-09-01—
Overall rank#4#8
Coding rank#4#12
Reasoning rank#4#6
Knowledge rank—#30
Professional work rank#4#2
Verified2026-10-192026-10-19
Price sourcePrice sourcePrice source

Cost per request by usage

Without cache discounts or batch pricing.

UsageClaude Fable 5.1Claude Sonnet 5.5Difference
Chat message1K in / 500 out$0.035$35 per 1,000$0.007$7 per 1,000Claude Sonnet 5.5 is 5× cheaper
Long document100K in / 2K out$1.1$1,100 per 1,000$0.22$220 per 1,000Claude Sonnet 5.5 is 5× cheaper
Agent session500K in / 50K out$7.5$7,500 per 1,000$1.5$1,500 per 1,000Claude Sonnet 5.5 is 5× cheaper

More price comparisons

Claude Fable 5.1 vs other models

Claude Sonnet 5.5 vs other models