Model comparison
Claude Sonnet 5.5 vs GLM 5.3: which is cheaper, and which should you use?
GLM 5.3 is cheaper: a support chatbot handling 1,000 requests a day costs about $91.40 a month on it against $169.57 on Claude Sonnet 5.5 (1.9×). Claude Sonnet 5.5 lists $2 input and $10 output per million tokens; GLM 5.3 lists $1.40 and $4.40. Context: 1,000,000 vs 1,048,576 tokens. Prices checked 2026-10-16.
Sonnet is Anthropic’s everyday model; GLM 5.3 is Z.ai’s open-weight flagship, popular as a cheaper option in coding tools. One is only on Anthropic’s API and its partners, the other you can also host yourself.
- Input / 1M
- $2
- Output / 1M
- $10
- Context
- 1,000,000
- Max output
- 128,000
- Input / 1M
- $1.40
- Output / 1M
- $4.40
- Context
- 1,048,576
- Max output
- Not published
This is Z.ai’s own API price, with cached input at $0.26 per million tokens. GLM 5.3 has open weights, so other hosts set their own prices.
Full GLM 5.3 pricing and specsVerdict
Which should you pick, Claude Sonnet 5.5 or GLM 5.3?
GLM 5.3 has the lower list prices: 1.4× cheaper per input token and 2.3× per output token. On our data, Claude Sonnet 5.5 has the edge for non-text inputs, repeated prompts and batch jobs, and GLM 5.3 for very long prompts and self-hosting. For scale, a support chatbot handling 1,000 requests a day costs about $169.57 a month on Claude Sonnet 5.5 and $91.40 on GLM 5.3.
- Lowest bill for typical workloadsEither
- It depends on the shape of the work: Claude Sonnet 5.5 is cheaper for the document summariser; GLM 5.3 for the support chatbot, RAG app and coding agent.
- Very long prompts (whole codebases, long documents)Pick GLM 5.3
- Both read about 1,000,000 tokens per request. One 800,000-token prompt with a 2,000-token reply costs $1.62 on Claude Sonnet 5.5 and $1.13 on GLM 5.3. Neither has a long-prompt surcharge in our data.
- Long replies (reports, large code files)Either
- Claude Sonnet 5.5 caps a reply at 128,000 tokens; GLM 5.3 publishes no separate cap, so we can’t say which allows longer replies.
- Images, audio, video or files in the promptPick Claude Sonnet 5.5
- Claude Sonnet 5.5 also accepts images and files, which GLM 5.3 doesn’t.
- Repeated long prompts (prompt caching)Pick Claude Sonnet 5.5
- Claude Sonnet 5.5 bills cached input at $0.10 per 1M (5% of its input price), against $0.26 per 1M (19% of its input price) for GLM 5.3.
- Overnight batch jobsPick Claude Sonnet 5.5
- Claude Sonnet 5.5 has a batch price ($1 in, $5 out per 1M); GLM 5.3 has none in our data.
- Self-hosting or choosing your own hostPick GLM 5.3
- GLM 5.3 has open weights, so you can run it yourself or pick a host; Claude Sonnet 5.5 is API-only.
Criteria use only list prices, published limits and the features each provider declares. We don’t rank answer quality; test both models on your own prompts before you commit.
Specs
How do Claude Sonnet 5.5 and GLM 5.3 compare on specs?
| Spec | Claude Sonnet 5.5 | GLM 5.3 |
|---|---|---|
| Provider | Anthropic | Z.ai |
| Input / 1M tokens | $2 | $1.40 (better) |
| Output / 1M tokens | $10 | $4.40 (better) |
| Cached input / 1M | $0.10 (better) | $0.26 |
| Cache write / 1M | $2.50 | No write charge listed |
| Batch in / out | $1 / $5 (better) | No batch price |
| Long-prompt price | None | None |
| Context window | 1,000,000 | 1,048,576 |
| Max output | 128,000 | Not published |
| Accepts | text, images, files | text |
| Image input | Yes (better) | No |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
| Prompt caching | Yes | Yes |
| Structured output | Yes | Yes |
| Open weights | No | Yes |
| Knowledge cutoff | Not published | Not published |
| First listed | 2026-09-28 | 2026-08-18 |
Prices in US dollars per million tokens. Highlighted: the lower price or larger limit where the difference is over 5%. Features are as declared by each provider’s API; “First listed” is when our data source first listed the model. Long-prompt prices apply to the whole request once the prompt passes the threshold.
Costs
What do Claude Sonnet 5.5 and GLM 5.3 cost for real workloads?
| Workload | Tokens in / out | Requests/day | Claude Sonnet 5.5 / month | GLM 5.3 / month | Cheaper |
|---|---|---|---|---|---|
| Support chatbotCalculator: Claude Sonnet 5.5 · GLM 5.3 | 1,500 / 400 | 1,000 | $169.5750% cached | $91.4050% cached | GLM 5.3 (1.9×) |
| RAG appCalculator: Claude Sonnet 5.5 · GLM 5.3 | 6,000 / 500 | 500 | $223.8720% cached | $140.4020% cached | GLM 5.3 (1.6×) |
| Coding agentCalculator: Claude Sonnet 5.5 · GLM 5.3 | 40,000 / 2,000 | 200 | $238.4780% cached | $172.2880% cached | GLM 5.3 (1.4×) |
| Document summariserCalculator: Claude Sonnet 5.5 · GLM 5.3 | 8,000 / 600 | 300 | $100.38batch | $126.29no batch price | Claude Sonnet 5.5 (1.3×) |
Each row uses the same token counts for both models and list prices (for an open-weight model, the top-ranked host’s price on OpenRouter), with caching and batch discounts only where the provider publishes them. A month is 365 ÷ 12 days. The support chatbot reads 50% of its prompt from the cache. The RAG app reads 20% of its prompt from the cache. The coding agent reads 80% of its prompt from the cache. The document summariser runs as a batch job where a batch price exists. Open either model in the LLM cost calculator to change any number.
Tokenizers
Are their per-token prices comparable?
Not exactly. Each model splits text into tokens its own way, so the same prompt can be a different number of tokens on Claude Sonnet 5.5 and GLM 5.3, and the cheaper per-token price isn’t always the cheaper bill. Where a tokenizer isn’t public or measured we say so rather than guess.
| Model | Tokenizer | Tokens per 1,000 words | Output per 1M words |
|---|---|---|---|
| Claude Sonnet 5.5 | Claude (Opus 4.7 and later)Provider’s published figure | 1,802 | $18.02 |
| GLM 5.3 | We haven’t measured GLM 5.3’s tokenizer, so its count for a given text isn’t known here. | ||
English prose, measured on the Universal Declaration of Human Rights (2026-10-11) or taken from the provider’s published words-per-token figure. Code, JSON and other languages use more tokens per word. Count your own text in the token counter or convert with tokens to words.
FAQ
Claude Sonnet 5.5 vs GLM 5.3 questions
Is Claude Sonnet 5.5 cheaper than GLM 5.3?
Claude Sonnet 5.5 costs $2 per million input tokens and $10 per million output tokens; GLM 5.3 costs $1.40 and $4.40. For a support chatbot handling 1,000 requests a day, that is about $169.57 a month on Claude Sonnet 5.5 against $91.40 on GLM 5.3, so GLM 5.3 is 1.9× cheaper there. Try your own numbers in the LLM cost calculator.
Which has the bigger context window, Claude Sonnet 5.5 or GLM 5.3?
Their context windows are about the same size. Claude Sonnet 5.5 reads up to 1,000,000 tokens (roughly 750,000 English words) and writes up to 128,000 tokens per reply. GLM 5.3 reads up to 1,048,576 tokens (roughly 786,432 English words) and publishes no separate cap on reply length. The window is shared between your prompt and the reply. Word counts use a rough 0.75 words per token; real ratios depend on the tokenizer.
Is Claude Sonnet 5.5 better than GLM 5.3?
We don’t score answer quality, so no page of ours can honestly say one is better overall. On what we can measure, Claude Sonnet 5.5 has the edge for non-text inputs, repeated prompts and batch jobs, and GLM 5.3 has the edge for very long prompts and self-hosting. Run both on a sample of your own prompts and compare the answers and the bill before you choose.
Can Claude Sonnet 5.5 and GLM 5.3 read images?
Claude Sonnet 5.5 accepts images and files as well as text. GLM 5.3 accepts text only. Only Claude Sonnet 5.5 can read screenshots, photos or scanned pages, so for image work the choice is made for you. This is what each provider declares for its API, not a measure of how well it works.
Can I switch from Claude Sonnet 5.5 to GLM 5.3 without rewriting my code?
Through OpenRouter, yes: both use the same OpenAI-compatible API, so you only change the model ID (anthropic/claude-sonnet-5.5 to z-ai/glm-5.3). Calling Anthropic and Z.ai directly, the request formats differ; the chat format converter translates between them. Re-test your prompts either way.
Are Claude Sonnet 5.5 and GLM 5.3 open source?
GLM 5.3 has open weights, so you can run it yourself or choose between hosting providers; its price here is a typical hosted price. Claude Sonnet 5.5 is closed: it’s only available through Anthropic’s API and its cloud partners. Check the licence before commercial use.
Do Claude Sonnet 5.5 and GLM 5.3 count tokens the same way?
Not necessarily. Each model splits text into tokens with its own tokenizer, so the same prompt can be a different number of tokens on each, and per-token prices aren’t directly comparable. Claude Sonnet 5.5 uses about 1,802 tokens per 1,000 English words (the provider’s published figure). We haven’t measured GLM 5.3’s tokenizer, so its count for a given text isn’t known here. Count your own text with the token counter or convert with tokens to words.