Claude Sonnet 5 vs GLM 5.3 Flash
Claude Sonnet 5 vs GLM 5.3 Flash: which AI model is cheaper, has the larger context window and more capabilities? Side-by-side comparison updated daily.
Quick verdict
- GLM 5.3 Flash is 17× cheaper than Claude Sonnet 5 for the same mix of input and output tokens.
- GLM 5.3 Flash has the larger context window (1M), useful for long documents and big codebases.
- GLM 5.3 Flash is the more recent release (Aug 26, 2026).
- Only GLM 5.3 Flash has openly published weights you can run yourself.
- Claude Sonnet 5 scores higher on independent tests (overall index 156.3 vs 151.9).
- Choose GLM 5.3 Flash if cost matters most; choose Claude Sonnet 5 if you need its specific strengths above. For the best results, test both on your own prompts.
| Claude Sonnet 5 | GLM 5.3 Flash | |
|---|---|---|
| Company | Anthropic | Z.ai (Zhipu) |
| Released | Jun 30, 2026 | Aug 26, 2026 ● |
| Overall index | 156.3 ● | 151.9 |
| GPQA Diamond | 90.5% ● | 90.2% |
| AIME math | 94.7% ● | 93.9% |
| FrontierMath | 65.6% ● | 55.8% |
| SimpleQA Verified | 33.7% | — |
| Input (per 1M tokens) | $2 | $0.15 ● |
| Output (per 1M tokens) | $10 | $0.50 ● |
| Cost for 1M input + 1M output tokens | $12.00 | $0.65 ● |
| Providers | 10 | 33 ● |
| Context | 1M | 1M ● |
| Max output | 128K | 944K ● |
| Inputs | Text, Image, Files | Text, Image, Video |
| Outputs | Text | Text |
| Reasoning | ✓ | ✓ |
| Tool use | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Open weights | — | ✓ |