AI model comparison
Mercury 2 vs GLM 4.5 Air
Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.
Inception
Mercury 2
Mercury 2 is an extremely fast reasoning LLM, and the first reasoning diffusion LLM (dLLM).
- Input / 1M
- $0.25
- Output / 1M
- $0.75
- Context
- 128K
Z.ai
GLM 4.5 Air
GLM-4.5-Air is the lightweight variant of our latest flagship model family, also purpose-built for agent-centric applications.
- Input / 1M
- $0.13
- Output / 1M
- $0.85
- Context
- 131K
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
GLM 4.5 Air
1.3x cheaper for a typical chat
Higher intelligence score
Mercury 2
13.8 vs 11.1 on Artificial Analysis
Larger context window
GLM 4.5 Air
131K vs 128K tokens
Newer release
Mercury 2
Released March 4, 2026
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
Mercury 213.8Coding index
Mercury 231.1Agentic index
Mercury 21.6Pricing
Mercury 2 vs GLM 4.5 Air API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | Mercury 2 | |
|---|---|---|
| Input tokensPer 1M tokens | $0.25 | $0.13 |
| Output tokensPer 1M tokens | $0.75 | $0.85 |
| Cached input (read)Per 1M tokens | $0.03 | $0.03 |
| Cache writePer 1M tokens | Not available | Not available |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
Mercury 2$0.88Coding task
30K in, 4K out
Mercury 2$10.50$3.75 cachedLong document summary
150K in, 2K out
Mercury 2$39$5.25 cachedSpecs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | Mercury 2 | |
|---|---|---|
| Context window | 128K tokens | 131K tokens |
| Max output | 50K tokens | 98K tokens |
| Input types | Text | Text |
| Output types | Text | Text |
| Reasoning effort levels | High, Medium, Low, None | Not available |
| Default reasoning effort | Medium | Not available |
| Release date | March 4, 2026 | July 25, 2025 |
Features
Supported features
API features available for each model.
| Metric | Mercury 2 | |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Not supported |
| JSON mode | Supported | Not supported |
| Reasoning | Supported | Supported |
| Temperature | Supported | Supported |
| Stop sequences | Supported | Supported |
| Deterministic seed | Not supported | Supported |
| Verbosity control | Not supported | Not supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
- GLM 4.5 Air vs Gemini 2.5 Flash Lite
- GLM 4.5 Air vs GPT-4.1 Mini
- GLM 4.5 Air vs Qwen3 235B A22B Instruct 2507
- GLM 4.5 Air vs GLM 4.7 Flash
- GLM 4.5 Air vs GLM 4.5
- GLM 4.5 Air vs Qwen3 Coder 480B A35B
- GLM 4.5 Air vs Qwen3 Coder Next
- GLM 4.5 Air vs Mistral Small 4
- GLM 4.5 Air vs Qwen3 Next 80B A3B Instruct
- GLM 4.5 Air vs GLM 4.6V
- GLM 4.5 Air vs Qwen3 Next 80B A3B Thinking
- GLM 4.5 Air vs Trinity Large Thinking
- GLM 4.5 Air vs Llama 4 Maverick
- GLM 4.5 Air vs GLM 4.5V
Our take
GLM 4.5 Air is 1.3x cheaper for a typical chat. Mercury 2 scores higher on the Artificial Analysis Intelligence Index (13.8 vs 11.1). GLM 4.5 Air has the larger context window (131K vs 128K tokens). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.
FAQ
Frequently asked questions
Is Mercury 2 or GLM 4.5 Air cheaper?
GLM 4.5 Air is cheaper for a typical chat (2K input tokens and 500 output tokens). GLM 4.5 Air costs $0.13 per 1M input tokens and $0.85 per 1M output tokens, while Mercury 2 costs $0.25 per 1M input tokens and $0.75 per 1M output tokens.
Which has a bigger context window, Mercury 2 or GLM 4.5 Air?
GLM 4.5 Air supports up to 131K tokens of context, compared with 128K for Mercury 2.
Is Mercury 2 smarter than GLM 4.5 Air?
On the Artificial Analysis Intelligence Index, Mercury 2 scores 13.8 and GLM 4.5 Air scores 11.1, putting Mercury 2 ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.
Can I use Mercury 2 and GLM 4.5 Air at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Mercury 2 and GLM 4.5 Air answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to Mercury 2 and GLM 4.5 Air at the same time. Compare the answers side by side and keep the best one.