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Claude Fable 5.1 vs GLM-5.3-Flash

Claude Fable 5.1Anthropic
GLM-5.3-FlashZ.ai
Our take

Claude Fable 5.1 wins 4 of 4 categories, but GLM-5.3-Flash is 84.2× cheaper for everyday text work. Pick Claude Fable 5.1 when quality matters most, GLM-5.3-Flash at volume.

Overall92Best55
Coding89Best69
Writing90Best64
Support83Best67
Value73Best60
Input / 1M$10.00$0.15Best
Output / 1M$50.00$0.50Best
Blended / 1M$20.00$0.24Best
Context window1M1M
Open weightsNoYes
Released1 Sept 202626 Aug 2026

Your monthly bill

50k
Claude Fable 5.1$4.0k
GLM-5.3-Flash$47.50Cheapest
List prices, a quarter of the tokens as output. Scores are provisional, from Arena and Epoch AI.