Google: Gemini 3.8 Flash (batch) vs Z.ai: GLM 5.3 Flash
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-09-27.
| Google: Gemini 3.8 Flash (batch) | Z.ai: GLM 5.3 Flash | |
|---|---|---|
| Vendor | z-ai | |
| Quality Score | 100 | 100 |
| Benchmark Score | 69.0 | 70.6 |
| Input Price | $0.38/M | $0.04/M |
| Output Price | $1.88/M | $0.14/M |
| Context Window | 1,048,576 | 1,310,720 |
| Max Output | 65,536 | 128,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | ✓ | - |
| Benchmark Scores | ||
| ai_index | 67.5 | 69.0 |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, GLM 5.3 Flash costs $0.080 and Gemini 3.8 Flash (batch) costs $0.84, so GLM 5.3 Flash is about 10.5 times cheaper for the same work.
Both take in a similar amount of text: 1,048,576 and 1,310,720 tokens, about 1,573 and 1,966 pages.
Only Gemini 3.8 Flash (batch) offers audio input.
On our blended benchmark score GLM 5.3 Flash leads 70.6 to 69.0.
Across the 18 tasks where they differ, GLM 5.3 Flash on 18 (SQL Generation, Code Review, Code Completion and others).
Gemini 3.8 Flash (batch) was released in September 2026 and GLM 5.3 Flash in August 2026.
Pick Gemini 3.8 Flash (batch) if you need audio input; pick GLM 5.3 Flash if you need lower cost, benchmark performance or the stronger all-round task scores.
Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.
Who wins by task?
| Task | Google: Gemini 3.8 Flash (batch) | Z.ai: GLM 5.3 Flash |
|---|---|---|
| SQL Generation | 141 | 142 |
| Code Review | 144 | 145 |
| Code Completion | 132 | 133 |
| Code Refactoring | 146 | 147 |
| Bug Fixing | 148 | 149 |
| Unit Test Generation | 132 | 132 |
| Code Documentation | 137 | 138 |
| Regex Writing | 126 | 126 |
| CI/CD Pipelines | 128 | 128 |
| Frontend Component Design | 130 | 130 |
| Data Analysis | 134 | 134 |
| CSV / Spreadsheet Cleanup | 136 | 136 |
| ETL Scripting | 137 | 137 |
| JSON Extraction | 131 | 132 |
| Bulk Data Labeling | 129 | 129 |
| Long-Document Summarization | 148 | 149 |
| Short-Form Summarization | 126 | 127 |
| Blog Post Writing | 129 | 130 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →