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Claude Opus 5.5 vs GLM-5.3-Flash

Claude Opus 5.5Anthropic
GLM-5.3-FlashZ.ai
Our take

Claude Opus 5.5 wins 4 of 4 categories, but GLM-5.3-Flash is 33.7× cheaper for everyday text work. Pick Claude Opus 5.5 when quality matters most, GLM-5.3-Flash at volume.

Overall97Best55
Coding100Best69
Writing100Best64
Support90Best67
Value83Best60
Input / 1M$4.00$0.15Best
Output / 1M$20.00$0.50Best
Blended / 1M$8.00$0.24Best
Context window1M1M
Open weightsNoYes
Released22 Sept 202626 Aug 2026

Your monthly bill

50k
Claude Opus 5.5$1.6k
GLM-5.3-Flash$47.50Cheapest
List prices, a quarter of the tokens as output. Scores are provisional, from Arena and Epoch AI.