Head to head

GLM-5.1 vs GLM-5.3

Price, context, inputs and filters. No benchmarks theatre.

Swap sides

GLM-5.3 costs 9× less per message.

GLM-5.3 holds 5.1× more context.

Fact

GLM-5.1Z.AI

OpenChat with GLM-5.1

GLM-5.3Z.AI

OpenChat with GLM-5.3

Made by

Z.AI

Content tier

Open

Intelligence

Brilliant

Smart & Cheap

Estimated price per message

~3.77 credits≈ 26 messages for 1 €

~0.42 credits≈ 238 messages for 1 €

Context window

205K tokens≈ 315 pages of text in one go

1M tokens≈ 1,613 pages of text in one go

Reads

Text

Writes

Text

Tool use

Yes - search, memory, code and more

Served via

OpenRouter, Unbottled AI

Status

Legacy

Current

A typical message: 16K tokens in, 1.5K out. Short replies cost less. Models served via OpenRouter bill the real provider cost plus our markup, so actual charges vary. 1 credit = 0.01 €.

GLM-5.1 details GLM-5.3 details