GLM-5.3-Flash vs GPT-5.1
GLM-5.3-Flash leads the LLM Stats Score 51.1 to 36.7. GLM-5.3-Flash is 14.5x cheaper per token.
Zhipu AI · OpenAI · Updated for 2026
Which is better?
GLM-5.3-Flash leads the overall LLM Stats Score 51.1 to 36.7, ranking #13 overall.
On price, GLM-5.3-Flash is roughly 14.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GLM-5.3-Flash also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GLM-5.3-Flash
- overall performance matters — it scores 51.1 and ranks #13 on LLM Stats
- your work emphasizes reasoning — it leads those capability indexes
- cost matters — it's about 14.5x cheaper per token
- you process long inputs — it offers a 1,048,576 token context window
- you want the most recent training data — it shipped Aug 2026
- you need open weights you can self-host or fine-tune
Choose GPT-5.1
- you want predictable pricing at $1.25/M input and $10.00/M output
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
15 reported for GLM-5.3-Flash · 9 for GPT-5.1
GLM-5.3-Flash and GPT-5.1don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GLM-5.3-Flash ($0.15/1M tokens) is 8.3x cheaper than GPT-5.1 ($1.25/1M tokens).
For output processing, GLM-5.3-Flash ($0.50/1M tokens) is 20.0x cheaper than GPT-5.1 ($10.00/1M tokens).
In conclusion, GPT-5.1 is more expensive than GLM-5.3-Flash.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GLM-5.3-Flash accepts 1,048,576 input tokens compared to GPT-5.1's 400,000 tokens. GLM-5.3-Flash can generate longer responses up to 131,072 tokens, while GPT-5.1 is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both GLM-5.3-Flash and GPT-5.1 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GLM-5.3-Flash
GPT-5.1
License
Usage and distribution terms
GLM-5.3-Flash is licensed under MIT, while GPT-5.1 uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
MIT
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
GLM-5.3-Flash was released on 2026-08-26, while GPT-5.1 was released on 2025-11-13.
GLM-5.3-Flash is 10 months newer than GPT-5.1.
Aug 26, 2026
1 weeks ago
9mo newerNov 13, 2025
9 months ago
Knowledge Cutoff
When training data ends
GPT-5.1 has a documented knowledge cutoff of 2024-09-30, while GLM-5.3-Flash's cutoff date is not specified.
We can confirm GPT-5.1's training data extends to 2024-09-30, but cannot make a direct comparison without GLM-5.3-Flash's cutoff date.
—
Sep 2024
Provider Availability
GLM-5.3-Flash is available from DeepInfra, FriendliAI, Novita, ZAI. GPT-5.1 is available from OpenAI.
GLM-5.3-Flash
GPT-5.1
Outputs Comparison
Judge for yourself.
Run your own prompts against GLM-5.3-Flash and GPT-5.1 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GLM-5.3-Flash vs GPT-5.1.