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Claude Sonnet 5.5 vs GLM-5.3

Claude Sonnet 5.5Anthropic
GLM-5.3Z.ai
Our take

Claude Sonnet 5.5 wins 4 of 4 categories, but GLM-5.3 is 1.9× cheaper for everyday text work. Pick Claude Sonnet 5.5 when quality matters most, GLM-5.3 at volume.

Overall79Best61
Coding87Best68
Writing74Best70
Support69Best67
Value69Best54
Input / 1M$2.00$1.40Best
Output / 1M$10.00$4.40Best
Blended / 1M$4.00$2.15Best
Context window1M1M
Open weightsNoYes
Released28 Sept 202614 Aug 2026

Your monthly bill

50k
Claude Sonnet 5.5$800
GLM-5.3$430Cheapest
List prices, a quarter of the tokens as output. Scores are provisional, from Arena and Epoch AI.