Question 1

Which is better, GLM-5.2 or GPT-5.5?

Accepted Answer

It depends on what you measure. Of the 5 public leaderboards that rate both, GLM-5.2 scores higher on 1 and GPT-5.5 on 4. GLM-5.2's widest lead is on LMArena; GPT-5.5's widest lead is on LiveBench. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, GLM-5.2 is at 31.8 and GPT-5.5 at 52.4 (out of 100).

Question 2

Which is newer, GLM-5.2 or GPT-5.5?

Accepted Answer

GLM-5.2. It went live on June 16, 2026, 53 days after GPT-5.5 (April 24, 2026).

Question 3

Which is cheaper, GLM-5.2 or GPT-5.5?

Accepted Answer

GLM-5.2 is cheaper on both input and output. On each vendor's own API, GLM-5.2 is $1.40 input / $4.40 output per million tokens and GPT-5.5 is $5 input / $30 output per million tokens. GPT-5.5's rate rises for prompts over 272K tokens. Prices as published in the models.dev catalog, as of 2026-09-24.

Question 4

Which has the bigger context window, GLM-5.2 or GPT-5.5?

Accepted Answer

GPT-5.5, at 1.05M tokens against GLM-5.2's 1M, as each vendor lists it.

Question 5

Who makes GLM-5.2 and GPT-5.5?

Accepted Answer

GLM-5.2 is from Zhipu AI; GPT-5.5 is from OpenAI.

Question 6

Where do these numbers come from?

Accepted Answer

Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed September 24, 2026). Boards measure different things, so raw scores are only comparable within a row.

Board	GLM-5.2	GPT-5.5	Higher
LMArena Elo (community votes)	1,599.5	1,532.4	GLM-5.2
LiveBench global average (0-100)	73.2	80.2	GPT-5.5
SimpleBench AVG@5 % (private set)	58.8	76.9	GPT-5.5
Vals AI Vals Index accuracy % · weighted finance + coding tasks	53.1	57.4	GPT-5.5
Artificial Analysis intelligence index · measured runs only	33.7	38.4	GPT-5.5

GLM-5.2 vs GPT-5.5

Leaderboard by leaderboard

GLM-5.2 at a glance

GPT-5.5 at a glance

GLM-5.2 vs GPT-5.5: quick answers