Gemini 3.5 Flash vs GLM 5.1
API pricing, context window and capabilities for Gemini 3.5 Flash and GLM 5.1, side by side. Prices are the cheapest serving route per 1M tokens, verified against LiteLLM and OpenRouter.
Verdict
computed from the published numbersGemini 3.5 Flash wins on coding, on intelligence and on context window. GLM 5.1 wins on price.
Price
GLM 5.1
Coding
Gemini 3.5 Flash
Intelligence
Gemini 3.5 Flash
Context window
Gemini 3.5 Flash
Key takeaways
who wins on what, from the published numbersGemini 3.5 Flash wins
- Larger context window (1M vs 203K)
- More serving providers (3 vs 2)
- Supports vision
- Supports audio
- Supports structured output
- Has web search
GLM 5.1 wins
- Cheaper input ($1.50 vs $1.05 /1M)
- Cheaper output ($9.00 vs $3.50 /1M)
- Higher max output (66K vs 128K)
Cheaper overall
GLM 5.1
$1.05 + $3.50 /1M
Larger context
Gemini 3.5 Flash
1M
More providers
Gemini 3.5 Flash
3 providers
Pricing & specs
cheapest serving route · per 1M tokens| Gemini 3.5 Flash | GLM 5.1 | |
|---|---|---|
| Input $/1M | $1.50 | $1.05 best |
| Output $/1M | $9.00 | $3.50 best |
| Context window | 1M best | 203K |
| Max output | 66K | 128K best |
| Serving providers | 3 best | 2 |
| Released | 2026-05-22 | 2026-04-07 |
Benchmarks
Artificial Analysis indices, side by side| Gemini 3.5 Flash | GLM 5.1 | |
|---|---|---|
| Intelligence | 50.2 best | 40.2 |
| Coding | 70.1 best | 55.8 |
| GPQA Diamond | 92% best | 87% |
| Output speed | 188 t/s best | 91 t/s |
| Latency (TTFT) | 18.79s | 10.49s best |
Cost calculator
choose a serving route for each sideInput tokens / month
Output tokens / month
Gemini 3.5 Flash
via Vertex AI
$17
GLM 5.1
via OpenRouter
$8.75
Capabilities
feature support, side by side| Feature | Gemini 3.5 Flash | GLM 5.1 |
|---|---|---|
| Vision | ✓ | — |
| Tool use | ✓ | ✓ |
| Reasoning | ✓ | ✓ |
| Audio | ✓ | — |
| Prompt caching | ✓ | ✓ |
| Structured output | ✓ | — |
| Web search | ✓ | — |
Related comparisons
Frequently asked questions
Which is cheaper, Gemini 3.5 Flash or GLM 5.1?
GLM 5.1 is cheaper for input ($1.50 vs $1.05 per 1M tokens). GLM 5.1 is cheaper for output ($9.00 vs $3.50 per 1M tokens).
What is the context window difference between Gemini 3.5 Flash and GLM 5.1?
Gemini 3.5 Flash has a 1M-token context window and GLM 5.1 has 203K tokens, so Gemini 3.5 Flash can take a larger prompt.
How do Gemini 3.5 Flash and GLM 5.1 compare on benchmarks?
On the tracked Artificial Analysis indices, Gemini 3.5 Flash leads on coding, and Gemini 3.5 Flash leads on intelligence.
Pricing verified against LiteLLM + OpenRouter + provider pages · refreshed daily
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