GLM-5.1 is getting attention because of its long-horizon coding performance, but the pricing question is less straightforward than it first appears. Teams evaluating it in May 2026 are really choosing between two very different buying models: standard API billing on one side, and Z.AI’s GLM Coding Plan for supported coding tools on the other.
If you miss that distinction, budgeting gets messy fast. The API path is token-metered. The Coding Plan path is quota-based, restricted to supported tools, and treats premium models like GLM-5.1 differently from cheaper defaults.
What GLM-5.1 API pricing costs in 2026
On Z.AI’s pricing page, GLM-5.1 is listed at $1.40 per 1 million input tokens and $4.40 per 1 million output tokens. Cached input is priced at $0.26 per 1 million tokens, and cached input storage is currently listed as limited-time free.
That makes GLM-5.1 a model that can look reasonable on input-heavy workloads, but get more expensive when your agent writes a lot, retries often, or spends long stretches reasoning and producing code, tests, and explanations.
| GLM-5.1 API item | Official price |
|---|---|
| Input | $1.40 / 1M tokens |
| Cached input | $0.26 / 1M tokens |
| Cached input storage | Limited-time free |
| Output | $4.40 / 1M tokens |
| Web Search tool | $0.01 per use |
That extra web search fee matters more than many teams expect. A tool-using coding or research workflow can stay modest on base tokens and still drift upward once search usage starts stacking across runs.
What the GLM Coding Plan actually includes
Z.AI also sells GLM through the GLM Coding Plan, which is designed for supported coding tools rather than general API usage. This is the path most people comparing it with Claude Code-style subscriptions are really looking for.
The current monthly plan pricing shown in Z.AI’s plan materials is:
| GLM Coding Plan | Monthly price | 5-hour limit | Weekly limit |
|---|---|---|---|
| Lite | $18 | Up to ~80 prompts | Up to ~400 prompts |
| Pro | $72 | Up to ~400 prompts | Up to ~2,000 prompts |
| Max | $160 | Up to ~1,600 prompts | Up to ~8,000 prompts |
Z.AI says one prompt is estimated to invoke the model around 15 to 20 times, and it frames the monthly quota as roughly 15x to 30x the subscription fee in API-equivalent value after weekly caps are factored in. That is useful directionally, but it is still not the same as having a guaranteed token allowance.
The other big detail is that the Coding Plan is not a general replacement for API billing. It is intended for approved tools such as Claude Code, Cline, and OpenCode. Z.AI explicitly notes that separate API calls are billed separately and do not consume Coding Plan quota.
Why GLM-5.1 can burn Coding Plan quota faster than expected
The most important fine print is that GLM-5.1 is treated as a premium model inside the plan. Z.AI says usage for GLM-5.1 and GLM-5-Turbo is deducted at 3x during peak hours and 2x during off-peak hours, because they are positioned closer to Opus-class usage than routine coding models.
There is also a temporary promotional carveout: off-peak GLM-5.1 usage is currently listed as 1x quota through the end of June 2026. That makes the plan materially more attractive for teams willing to batch heavier work outside peak windows.
In practice, this means the headline plan price can be misleading if you assume every prompt costs the same. It does not. A team using GLM-4.7 for most work and reserving GLM-5.1 for hard tasks will stretch a plan much further than a team that runs GLM-5.1 as the default for everything.
API vs Coding Plan: which pricing path is better?
Choose API billing if:
- you need GLM-5.1 outside approved coding tools
- you are building your own product or agent backend
- you want predictable token-level metering
- you need to mix GLM with custom orchestration, agents, or pipelines
Choose GLM Coding Plan if:
- your main use case is inside supported coding tools
- you want a lower-friction subscription instead of variable token bills
- you can manage model selection carefully
- you are comfortable using GLM-4.7 for routine work and GLM-5.1 selectively
For most individual developers and small teams, the Coding Plan is the better answer if the workflow fits the supported-tool boundary. For product teams and agent builders, API billing is usually the cleaner choice because it avoids plan restrictions and makes cost modeling easier inside software.
What teams should actually budget for GLM-5.1
A practical way to think about GLM-5.1 pricing is to separate three scenarios.
Light experimentation: start with Lite if your work is mostly personal coding inside a supported tool and you only need GLM-5.1 occasionally.
Serious day-to-day coding: Pro is the more realistic floor for teams or power users, but only if they avoid running GLM-5.1 as the default on every prompt.
Production agents or productized workflows: use the API rate card and model token economics directly. The Coding Plan is not designed to be your backend billing layer.
The broader takeaway is simple: GLM-5.1 is not expensive in only one way. It can be cheap on cached, input-heavy workflows, costly on output-heavy agent runs, and surprisingly efficient on the Coding Plan if you use it as a premium escalation model rather than your default.
That is the budgeting mindset that matters most in 2026.