Price
GLM-5.3 FlashFlash costs $0.0052 / $0.1985 per million tokens against $0.079 / $1.40 for GLM-5.3.
compare/glm-5-3-vs-glm-5-3-flash
Comparison · inside the family
GLM-5.3 vs GLM-5.3 Flash
Our free chat runs both GLM-5.3 and GLM-5.3 Flash, so this is the comparison you can test immediately. They share a context window but differ in size, price, inputs and licence. We also place FlashX and Prime on the same sheet.
Data-backed verdicts
GLM-5.3
1
GLM-5.3 Flash
4
Tie: 1 · counted from the six verdicts below
§ 01Specs
Specification matrix
OpenRouter data for the models compared on this page. Lowest prices and largest limits are highlighted.
| Model | GLM-5.3 | GLM-5.3 Flash | GLM-5.3 FlashX | GLM-5.3 Prime |
|---|---|---|---|---|
| Developer | Z.ai | Z.ai | Z.ai | Z.ai |
| Released | Aug 18, 2026 | Aug 26, 2026 | Sep 18, 2026 | Sep 23, 2026 |
| Context window | 1.05M | 1.05M | 1.05M | 1M |
| Max output | 944K | 944K | 131K | 131K |
| Input price | $0.079 | $0.0052 | $0.37 | $2.80 |
| Output price | $1.40 | $0.1985 | $1.25 | $8.80 |
| Inputs | Text | Text, Image, Video | Text, Image, Video | Text |
| Open weights | Yes (Hugging Face) | Yes (Hugging Face) | No | No |
| Free chat here | In our chat | In our chat | — | — |
Prices are USD per 1 million tokens as listed by OpenRouter; the best value in each row is highlighted. Source: OpenRouter model list and the official Hugging Face model cards.
§ 02Analysis
What the numbers mean
Two different models, not one model in two sizes
GLM-5.3 uses the same base model as GLM-5.2 and gains everything from post-training, according to Z.ai. GLM-5.3 Flash starts from a newly trained base model with a hybrid sparse and linear attention design, 320 billion parameters in total and 18 billion active per token, and native multimodal input.
Z.ai positions GLM-5.3 for the hardest software engineering and long-horizon agent tasks, and GLM-5.3 Flash for efficient coding and agents at a much lower cost. Z.ai says Flash outperforms GLM-5.2, the model GLM-5.3 is built on, at one-tenth of the price.
Price, inputs and licence
On OpenRouter, GLM-5.3 costs $0.079 per million input tokens and $1.40 per million output tokens. GLM-5.3 Flash costs $0.0052 and $0.1985 — about fifteen times cheaper on input and seven times cheaper on output.
Flash reads text, images and video; GLM-5.3 reads text only. Flash is released under the MIT licence, while GLM-5.3 uses a custom licence. Both list a context of 1,048,576 tokens and a maximum output of 943,718 tokens.
FlashX and Prime: the fast lanes
Each model has an API-only speed variant. GLM-5.3 FlashX is the high-speed version of Flash, up to 200 tokens per second, at $0.37 and $1.25 per million tokens. GLM-5.3 Prime is GLM-5.3 with 1.5–2× the output throughput, at $2.80 and $8.80. Both list a maximum output of 131,072 tokens.
In our chat, GLM-5.3 Flash is the default and has generous daily limits; GLM-5.3 has a smaller daily quota because it costs more to run.
- Everyday tasks, images, translation: GLM-5.3 Flash.
- Hard code, long reasoning: GLM-5.3.
- Need speed over price: FlashX or Prime via API.
§ 03Verdicts
Six questions, six answers
Image and video input
GLM-5.3 FlashFlash reads images and video; GLM-5.3 is text-only.
Hardest coding and long tasks
GLM-5.3Z.ai positions GLM-5.3 as its model for complex software engineering and long-horizon agents.
Permissive licence
GLM-5.3 FlashFlash is MIT-licensed; GLM-5.3 uses a custom licence.
Context window
TieBoth list 1,048,576 tokens of context and 943,718 output tokens.
Daily availability here
GLM-5.3 FlashFlash is the default with generous limits; GLM-5.3 has a smaller daily quota in our chat.
Bottom line
Use GLM-5.3 Flash by default — it is cheaper, reads images and is fully MIT. Switch to GLM-5.3 when a problem is hard enough that you want Z.ai's strongest reasoning model on it.
Pick GLM-5.3 if…
- you are debugging tricky code or refactoring across files
- you need careful multi-step reasoning
- quality matters more than speed or cost
Pick GLM-5.3 Flash if…
- you want fast answers for everyday work
- you want to ask about images or video
- you need the MIT licence for the weights
- you send large volumes of text
§ 04FAQ
Common questions
Q01Is GLM-5.3 Flash a smaller GLM-5.3?
Not exactly. It is a separate model trained from a new base, with a different attention architecture and native multimodal input.
Q02Which one should I use in the chat?
Start with GLM-5.3 Flash. If an answer is not good enough on a hard problem, regenerate it with GLM-5.3.
Q03Why is GLM-5.3 limited per day here?
It costs more to run than Flash, so each visitor gets a smaller free daily quota for GLM-5.3. Flash keeps working when the quota is used.
Q04Can GLM-5.3 read images?
No. When you attach an image, our chat sends it to GLM-5.3 Flash.
§ 05More
Other comparisons
Try it now
Ask GLM-5.3 something real.
No account, no card, no install. Type a question and watch GLM-5.3 Flash answer in seconds — switch to GLM-5.3 for the hardest problems.
Open the free chatFree daily limits apply so the chat stays open for everyone.