GLM 5.3 Flash vs gpt-oss-20b: pricing comparison
gpt-oss-20b is the cheaper option at $0.02/$0.09 per 1M input/output tokens — GLM 5.3 Flash ($0.15/$0.50) costs about 8.3x more per input token. Full spec-by-spec breakdown below.
| GLM 5.3 Flash | gpt-oss-20b | |
|---|---|---|
| Input /1M tokens | $0.15 | $0.02 |
| Output /1M tokens | $0.50 | $0.09 |
| Cache read /1M | $0.03 | $0.01 |
| Context window | 1.0M | 131K |
| Provider | Z-ai | OpenAI |
| Vision input | Yes | No |
| Released | Aug 2026 | Aug 2025 |
Real workload costs: GLM 5.3 Flash vs gpt-oss-20b
Cost per single request at common token profiles — the cheapest model for each workload is highlighted.
| Workload | Tokens (in / out) | GLM 5.3 Flash | gpt-oss-20b |
|---|---|---|---|
| Chatbot message | 500 / 300 | $0.0002 | <$0.0001 |
| RAG query with context | 4,000 / 500 | $0.0008 | $0.0001 |
| Document summarization | 20,000 / 1,000 | $0.0035 | $0.0004 |
| Agent coding session | 100,000 / 5,000 | $0.02 | $0.0022 |
Frequently asked questions
Which is cheaper: GLM 5.3 Flash vs gpt-oss-20b?
gpt-oss-20b is the cheapest on input tokens at $0.02 per 1M, and gpt-oss-20b is cheapest on output at $0.09 per 1M. GLM 5.3 Flash costs about 8.3x more per input token than gpt-oss-20b.
How much does GLM 5.3 Flash cost per 1M tokens?
GLM 5.3 Flash costs $0.15 per 1M input tokens and $0.50 per 1M output tokens on the Z-ai API, with a 1.0M-token context window.
How much does gpt-oss-20b cost per 1M tokens?
gpt-oss-20b costs $0.02 per 1M input tokens and $0.09 per 1M output tokens on the OpenAI API, with a 131K-token context window.
What does a typical request cost on GLM 5.3 Flash vs gpt-oss-20b?
For a typical request with 2,000 input and 500 output tokens: GLM 5.3 Flash costs $0.0006, gpt-oss-20b costs <$0.0001. At 1,000 requests/day for a month that is $16.50 for GLM 5.3 Flash vs $2.43 for gpt-oss-20b.
Estimate your own workload with the per-model calculators (GLM 5.3 Flash, gpt-oss-20b), browse all current prices on the live model pricing dashboard, or run these models head-to-head on a real prompt (free account required). Prices may differ from provider list prices for batch or tiered usage.
Pricing data via the OpenRouter models API.