text model comparison
GLM-5.3-Flash vs GPT-6 Astra
GLM-5.3-Flash and GPT-6 Astra are both current text models, from Z.ai and OpenAI. GLM-5.3-Flash is 99% cheaper per 1M input tokens than GPT-6 Astra, $0.15 vs $10. On Arena Text, GLM-5.3-Flash scores 1475 Elo and GPT-6 Astra 1475 Elo (Arena, measured October 8, 2026). GPT-6 Astra has the larger context window, 1,050,000 vs 1,000,000 tokens.
Data verified October 13, 2026 · Dataset 2026-10-13
Side by side
Standard-tier prices in effect today. The better value in each row is highlighted.
| Fact | GLM-5.3-Flash | GPT-6 Astra |
|---|---|---|
| Price per 1M input tokens | $0.15 (better) | $10 |
| Price per 1M output tokens | $0.50 (better) | $50 |
| Cost of 10M input and 2M output tokens | $2.50 (better) | $200 |
| Arena Text | 1475 Elo (#21 of 49) | 1475 Elo (#21 of 49) |
| GPQA Diamond | 90.2% (#27 of 40) | 95.8% (#1 of 40) (better) |
| FrontierMath Tiers 1-3 (v2) | 55.8% (#31 of 40) | 93.7% (#1 of 40) (better) |
| SimpleQA Verified | Not measured | 75.6% (#1 of 36) |
| Provider | Z.ai | OpenAI |
| Release date | August 26, 2026 | September 3, 2026 |
| Access | API and open weights | API only |
| Context window | 1,000,000 tokens | 1,050,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Input | text, image, video | text, image |
| Output | text | text |
When to choose each
GLM-5.3-Flash
Best for
- Low-cost coding from screenshots or screen recordings
- Document and research agents on a budget
Watch out for
- Thinking cannot be disabled
- A faster GLM-5.3-FlashX is a separate model id at $0.37 input and $1.25 output per 1M tokens
GPT-6 Astra
Best for
- Frontier reasoning and agentic evaluations where deep-context retrieval accuracy is the binding constraint
- Workloads that can be kept under the long-context threshold, where the effective rate stays at $10 / $50
Watch out for
- Long-context billing is a cliff, not a taper: a request over the long-context threshold is rebilled in full at $20 per million input and $75 per million output, so a prompt that crosses it costs roughly double
- GPT-6 Astra is the first publicly released model OpenAI classifies as crossing the Critical cybersecurity threshold under its own Preparedness Framework, which carries additional deployment safeguards
- Vendor-reported benchmark figures come from OpenAI’s own launch material and its own harness; they are not independently reproduced here
GLM-5.3-Flash vs GPT-6 Astra FAQ
Which is cheaper, GLM-5.3-Flash or GPT-6 Astra?
GLM-5.3-Flash is 99% cheaper per 1M input tokens than GPT-6 Astra, $0.15 vs $10. For 10M input and 2M output tokens, GLM-5.3-Flash costs $2.50 and GPT-6 Astra $200 at standard rates.
Which scores higher on independent benchmarks, GLM-5.3-Flash or GPT-6 Astra?
Both score 1475 Elo on Arena Text; GPT-6 Astra leads on GPQA Diamond, 95.8% to 90.2%; GPT-6 Astra leads on FrontierMath Tiers 1-3 (v2), 93.7% to 55.8%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, GLM-5.3-Flash or GPT-6 Astra?
GPT-6 Astra has the larger context window, 1,050,000 vs 1,000,000 tokens.
Can I run GLM-5.3-Flash or GPT-6 Astra myself?
GLM-5.3-Flash is released as open weights you can run yourself; GPT-6 Astra is available through its provider's API only.
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Production evaluation
Choosing between GLM-5.3-Flash and GPT-6 Astra?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
- Routing between models by cost and difficulty