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compare/glm-5-vs-gpt-6

Comparison · open vs OpenAI

GLM-5 vs GPT-6

OpenAI's GPT-6 family comes in three tiers: Astra, Sol and Luna. GLM-5 answers with GLM-5.3 and GLM-5.3 Flash. Both sides offer about a million tokens of context; the differences are price, inputs and openness.
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Data-backed verdicts

GLM-5

2

vs

GPT-6

2

Tie: 2 · 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.

GLM-5 vs GPT-6
ModelGLM-5.3GLM-5.3 FlashGPT-6 AstraGPT-6 SolGPT-6 Luna
DeveloperZ.aiZ.aiOpenAIOpenAIOpenAI
ReleasedAug 18, 2026Aug 26, 2026Sep 4, 2026Sep 22, 2026Sep 22, 2026
Context window1.05M1.05M1.05M1.05M1.05M
Max output944K944K128K128K128K
Input price$0.079$0.0052$10$2$0.1
Output price$1.40$0.1985$50$10$0.5
InputsTextText, Image, VideoText, Image, FilesText, Image, FilesText, Image, Files
Open weightsYes (Hugging Face)Yes (Hugging Face)NoNoNo
Free chat hereIn our chatIn 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

Prices across the tiers

GPT-6 Astra is the premium tier at $10 per million input tokens and $50 per million output tokens. GPT-6 Sol costs $2 and $10, and GPT-6 Luna $0.10 and $0.50. On the GLM side, GLM-5.3 costs $0.079 and $1.40, and GLM-5.3 Flash $0.0052 and $0.1985.

Compared tier for tier, GLM-5.3 is cheaper than GPT-6 Sol on input by a factor of about 25 and on output by about 7. GLM-5.3 Flash undercuts GPT-6 Luna on both input and output. For high-volume work, that adds up quickly.

Inputs and limits

All three GPT-6 tiers accept text, images and files. GLM-5.3 Flash accepts text, images and video; GLM-5.3 is text-only. If you want one top-tier model that takes PDFs and screenshots directly, GPT-6 Sol or Astra is the simpler choice.

Context is a tie: GPT-6 lists 1,050,000 tokens and GLM 1,048,576. Maximum output is 128,000 tokens for GPT-6 Astra; the GLM models list 943,718, which gives far more room for long outputs.

Openness and languages

GPT-6 models are available only through OpenAI and its partners. GLM-5.3 and GLM-5.3 Flash have official open weights, so you can run them yourself if you need to.

Both families are used in many languages. We cannot honestly declare a winner for writing quality in your language from specs alone — the fastest way to decide is to ask the same question in our free GLM chat and in the assistant you use today.

  • Cheaper at every tier: GLM.
  • File input on every tier: GPT-6.
  • Context: a tie at about one million tokens.

§ 03Verdicts

Six questions, six answers

Price

GLM-5

GLM-5.3 Flash costs $0.0052 / $0.1985 per million tokens against $0.10 / $0.50 for GPT-6 Luna.

Open weights

GLM-5

GLM-5.3 and GLM-5.3 Flash have Hugging Face repositories; GPT-6 is closed.

File input

GPT-6

Every GPT-6 tier lists file input; the GLM models do not.

Image input on the flagship

GPT-6

GPT-6 Sol reads images; GLM-5.3 is text-only and leaves images to GLM-5.3 Flash.

Context window

Tie

1,050,000 tokens for GPT-6 and 1,048,576 for GLM — effectively equal.

Writing in many languages

Tie

Both are widely used across languages; quality depends on the language and task, so test your own.

Bottom line

GLM-5 offers the same context at a fraction of GPT-6's price, plus open weights. GPT-6 is more convenient when you want file and image input on a single top-tier model.

Pick GLM-5 if…

  • price per token is a deciding factor
  • you want the option to self-host
  • you need long outputs in one request
  • you want to try a strong model free without an account

Pick GPT-6 if…

  • you need file input on the flagship
  • you want image input on the top tier
  • your product is built on OpenAI's platform features

§ 04FAQ

Common questions

Q01Is GLM-5 a free alternative to GPT-6?

In our chat, yes: GLM-5.3 Flash and GLM-5.3 are free without sign-up within daily limits. Through APIs, GLM is much cheaper than GPT-6 but not free.

Q02Which has the longer context, GLM-5 or GPT-6?

They are practically equal: 1,048,576 tokens for GLM-5.3 and 1,050,000 for GPT-6.

Q03Can I switch my GPT-6 app to GLM-5?

Usually yes. Both use the OpenAI-style chat completions format, so you change the base URL and model name. See our API guide.

Q04Does GLM-5 read files like GPT-6?

Not as file attachments. Paste the text or send page images to GLM-5.3 Flash.

§ 05More

Other comparisons

GLM-5 vs DeepSeek V4GLM-5 vs Qwen3.7GLM-5 vs ClaudeGLM-5 vs GeminiGLM-5.3 vs GLM-5.3 FlashAll comparisons

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