GLM 5.3 Flash vs GPT-6 Astra
API pricing, context window and capabilities for GLM 5.3 Flash and GPT-6 Astra, side by side. Prices are the cheapest listed serving route per 1M tokens, from LiteLLM and OpenRouter.
Verdict
computed from the published numbersGLM 5.3 Flash wins on price. GPT-6 Astra wins on Terminal-Bench, on intelligence and on context window.
Price
GLM 5.3 Flash
Terminal-Bench
GPT-6 Astra
Intelligence
GPT-6 Astra
Context window
GPT-6 Astra
Key takeaways
who wins on what, from the published numbersGLM 5.3 Flash wins
- Cheaper input ($0.11 vs $10.00 /1M)
- Cheaper output ($0.35 vs $50.00 /1M)
- Higher max output (1M vs 128K)
- More serving providers (13 vs 5)
GPT-6 Astra wins
- Larger context window (1M vs 1.1M)
- Has web search
Cheaper overall
GLM 5.3 Flash
$0.11 + $0.35 /1M
Larger context
GPT-6 Astra
1.1M
More providers
GLM 5.3 Flash
13 providers
Pricing & specs
cheapest listed route · per 1M tokensOn-demand listed rates, OpenRouter routed quotes and Vercel reseller quotes. Enterprise commitments can be materially lower.
| GLM 5.3 Flash | GPT-6 Astra | |
|---|---|---|
| Input $/1M | $0.11via Sail best | $10.00via OpenAI |
| Output $/1M | $0.35via Sail best | $50.00via OpenAI |
| Context window | 1M | 1.1M best |
| Max output | 1M best | 128K |
| Serving providers | 13 best | 5 |
| Date | Released Aug 26, 2026 | Released Sep 4, 2026 |
Benchmarks
Benchmark scores, side by side| GLM 5.3 Flash | GPT-6 Astra | |
|---|---|---|
| Intelligence | 41.8 | 52.7 best |
| Terminal-Bench | 84% | 88% best |
| GPQA Diamond | 91% | 96% best |
| Output speed | 67 t/s best | 61 t/s |
| Latency (TTFT) | 2.80s best | 280.05s |
Cost calculator
choose a serving route for each sideInput tokens / month
Output tokens / month
GLM 5.3 Flash
via Sail
$0.90
GPT-6 Astra
via OpenAI
$100
Capabilities
feature support, side by side| Feature | GLM 5.3 Flash | GPT-6 Astra |
|---|---|---|
| Vision | ✓ | ✓ |
| Tool use | ✓ | ✓ |
| Reasoning | ✓ | ✓ |
| Audio | — | — |
| Prompt caching | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Web search | — | ✓ |
Related comparisons
Frequently asked questions
Which is cheaper, GLM 5.3 Flash or GPT-6 Astra?
GLM 5.3 Flash is cheaper for input ($0.11 vs $10.00 per 1M tokens) from Sail. GLM 5.3 Flash is cheaper for output ($0.35 vs $50.00 per 1M tokens) from Sail.
What is the context window difference between GLM 5.3 Flash and GPT-6 Astra?
GLM 5.3 Flash has a 1M-token context window and GPT-6 Astra has 1.1M tokens, so GPT-6 Astra can take a larger prompt.
How do GLM 5.3 Flash and GPT-6 Astra compare on benchmarks?
On the tracked benchmarks, GPT-6 Astra leads on Terminal-Bench, and GPT-6 Astra leads on intelligence.
Listed prices from LiteLLM, OpenRouter and Vercel · last checked Oct 14, 2026
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