Verdict
computed from the published numbersGLM 5.1 wins on price. GPT-5.5 wins on coding, on intelligence and on context window.
Price
GLM 5.1
Coding
GPT-5.5
Intelligence
GPT-5.5
Context window
GPT-5.5
Key takeaways
who wins on what, from the published numbersGLM 5.1 wins
- Cheaper input ($0.97 vs $5.00 /1M)
- Cheaper output ($3.04 vs $30.00 /1M)
- Higher max output (131K vs 128K)
- More serving providers (5 vs 3)
GPT-5.5 wins
- Larger context window (205K vs 1.1M)
- Supports vision
- Has web search
Cheaper overall
GLM 5.1
$0.97 + $3.04 /1M
Larger context
GPT-5.5
1.1M
More providers
GLM 5.1
5 providers
Pricing & specs
cheapest serving route · per 1M tokens| GLM 5.1 | GPT-5.5 | |
|---|---|---|
| Input $/1M | $0.97 best | $5.00 |
| Output $/1M | $3.04 best | $30.00 |
| Context window | 205K | 1.1M best |
| Max output | 131K best | 128K |
| Serving providers | 5 best | 3 |
| Released | 2026-04-07 | 2026-04-23 |
Benchmarks
Artificial Analysis indices, side by side| GLM 5.1 | GPT-5.5 | |
|---|---|---|
| Intelligence | 41.0 | 56.3 best |
| Coding | 55.8 | 74.9 best |
| GPQA Diamond | 87% | 94% best |
| Output speed | 61 t/s | 83 t/s best |
| Latency (TTFT) | 1.70s best | 59.21s |
Cost calculator
choose a serving route for each sideInput tokens / month
Output tokens / month
GLM 5.1
via OpenRouter
$7.87
GPT-5.5
via Azure
$55
Capabilities
feature support, side by side| Feature | GLM 5.1 | GPT-5.5 |
|---|---|---|
| Vision | — | ✓ |
| Tool use | ✓ | ✓ |
| Reasoning | ✓ | ✓ |
| Audio | — | — |
| Prompt caching | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Web search | — | ✓ |
Related comparisons
Frequently asked questions
Which is cheaper, GLM 5.1 or GPT-5.5?
GLM 5.1 is cheaper for input ($0.97 vs $5.00 per 1M tokens). GLM 5.1 is cheaper for output ($3.04 vs $30.00 per 1M tokens).
What is the context window difference between GLM 5.1 and GPT-5.5?
GLM 5.1 has a 205K-token context window and GPT-5.5 has 1.1M tokens, so GPT-5.5 can take a larger prompt.
How do GLM 5.1 and GPT-5.5 compare on benchmarks?
On the tracked Artificial Analysis indices, GPT-5.5 leads on coding, and GPT-5.5 leads on intelligence.
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