Is GLM 5.3 better than GLM 5.3 Flash?

On accuracy they are statistically tied: GLM 5.3 scored 67.5% and GLM 5.3 Flash 67.5% on the same 80 questions from open datasets. Similar accuracy; GLM 5.3 Flash costs less per question.

Which is cheaper, GLM 5.3 or GLM 5.3 Flash?

GLM 5.3 Flash is cheaper: $0.00015 per question as billed, against $0.00093. List prices: GLM 5.3 $0.079 in / $1.4 out, GLM 5.3 Flash $0.15 in / $0.5 out per million tokens.

Which is faster, GLM 5.3 or GLM 5.3 Flash?

GLM 5.3 is faster at 154 output tokens per second, against 83. Time to first token: 0.8 s for GLM 5.3, 0.5 s for GLM 5.3 Flash.

Which has the larger context window, GLM 5.3 or GLM 5.3 Flash?

Both accept about the same amount of context: 1M and 1M tokens.

Head to head · tested 27 Oct 2026

GLM 5.3 vs GLM 5.3 Flash: accuracy, speed and price

Similar accuracy; GLM 5.3 Flash costs less per question.

Z.aiGLM 5.367.5% score · #28$0.00093 per question154 tok/s

Z.aiGLM 5.3 Flash67.5% score · #28$0.00015 per question83 tok/s

Verdict

Built from the measurements below

Accuracy is too close to call: GLM 5.3 scored 67.5% and GLM 5.3 Flash 67.5% on the same 80 questions, a gap within what chance alone could produce.
GLM 5.3 Flash is 6.4× cheaper per question as billed ($0.00015 vs $0.00093), reasoning tokens included.
GLM 5.3 generates text 1.8× faster: 154 tokens per second against 83.
GLM 5.3 Flash starts answering sooner: 0.5 s to the first token, against 0.8 s for GLM 5.3.

Which should you choose?

Choose GLM 5.3 for faster streaming and more hosts to choose from on OpenRouter (37 against 34). Choose GLM 5.3 Flash for the lower cost per correct answer ($0.00022 against $0.0014) and a quicker first token. The widest subject gap is in engineering: GLM 5.3 answered 10 of 15 correctly, GLM 5.3 Flash 8 of 15. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.

Accuracy gap +0.0 points (z = 0.00). A winner is called only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.

Head to head

Same questions, same prompt, same API

Measure	GLM 5.3	GLM 5.3 Flash	Edge
Verification scoreHigher is better	67.5%	67.5%	Too close to call
Cost per questionLower is better	$0.00093	$0.00015	GLM 5.3 Flash
Output speedHigher is better	154	83	GLM 5.3
Time to first tokenLower is better	0.8 s	0.5 s	GLM 5.3 Flash
End-to-end response timeLower is better	3.4 s	7.4 s	GLM 5.3
Tokens per questionLower is better	523	560	Similar
Context windowHigher is better	1M	1M	Similar

Side by side

Bars are scaled to the larger of the two values. The winner on each measure is marked in bold.

Every measure

GLM 5.3 first, GLM 5.3 Flash second

Verification scorehigher is better

GLM 5.367.5%

GLM 5.3 Flash67.5%

Cost per questionlower is better

GLM 5.3$0.00093

GLM 5.3 Flash$0.00015

Output speedhigher is better

GLM 5.3154

GLM 5.3 Flash83

Time to first tokenlower is better

GLM 5.30.8 s

GLM 5.3 Flash0.5 s

End-to-end response timelower is better

GLM 5.33.4 s

GLM 5.3 Flash7.4 s

Tokens per questionlower is better

GLM 5.3523

GLM 5.3 Flash560

Context windowhigher is better

GLM 5.31M

GLM 5.3 Flash1M

Score vs. cost per question

Both models in color, every other model in grey

Results by subject and dataset

Questions answered correctly. Small samples: a gap of one or two questions is noise.

Subject	Questions	GLM 5.3	GLM 5.3 Flash
Science	30	20/30	22/30
Engineering	15	10/15	8/15
Medicine	11	5/11	5/11
Economics	9	7/9	7/9
Law	6	4/6	4/6
Humanities & social science	9	8/9	8/9
SuperGPQA dataset	50	27/50	27/50
MMLU-Pro dataset	30	27/30	27/30

Specifications and pricing

From OpenRouter's catalogue, plus the leaderboard's test dates

Specification	GLM 5.3	GLM 5.3 Flash
Creator	Z.ai	Z.ai
Released	18 Aug 2026	26 Aug 2026
Weights	Open weights	Open weights
Reasoning	Yes	Yes
Input	text	text, image, video
Output	text	text
Context window	1M tokens	1M tokens
Knowledge cutoff	—	—
List price in / out per 1M	$0.079 / $1.4	$0.15 / $0.5
Blended price per 1M (3:1)	$0.41	$0.24
Cheapest host	Wafer · $0.0699 / $1.4	Relace · $0.0379 / $0.074
Hosts on OpenRouter	37	34
Last tested	25 Oct 2026	26 Oct 2026

Compare any two models →

GLM 5.3 vs GLM 5.3 Flash: frequently asked questions

Is GLM 5.3 better than GLM 5.3 Flash?: On accuracy they are statistically tied: GLM 5.3 scored 67.5% and GLM 5.3 Flash 67.5% on the same 80 questions from open datasets. Similar accuracy; GLM 5.3 Flash costs less per question.
Which is cheaper, GLM 5.3 or GLM 5.3 Flash?: GLM 5.3 Flash is cheaper: $0.00015 per question as billed, against $0.00093. List prices: GLM 5.3 $0.079 in / $1.4 out, GLM 5.3 Flash $0.15 in / $0.5 out per million tokens.
Which is faster, GLM 5.3 or GLM 5.3 Flash?: GLM 5.3 is faster at 154 output tokens per second, against 83. Time to first token: 0.8 s for GLM 5.3, 0.5 s for GLM 5.3 Flash.
Which has the larger context window, GLM 5.3 or GLM 5.3 Flash?: Both accept about the same amount of context: 1M and 1M tokens.