Claude Opus 5.5 vs GLM-5.3-Flash
Claude Opus 5.5 (Anthropic) and GLM-5.3-Flash (Z.ai (Zhipu AI)) compared on benchmarks, pricing, context window, and use-case rankings.
- Claude Opus 5.5 leads on overall intelligence (ECI 167 vs 153).
- GLM-5.3-Flash is cheaper on input tokens: $0.13 vs $4.00 per 1M.
- Claude Opus 5.5 ranks higher for coding (100th vs 75th percentile).
| Attribute | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 167 | 153 |
| Coding | 100 | 75 |
| Math | 88 | 52 |
| Reasoning & Knowledge | 90 | 52 |
| Agentic & Tools | 97 | 69 |
| Specifications | ||
| Developer | Anthropic | Z.ai (Zhipu AI) |
| Family | Claude | — |
| Released | Sep 22, 2026 | Aug 20, 2026 |
| Parameters | — | 320B |
| Availability | API access | Open weights (unrestricted) |
| Context window | 1M | 1M |
| Price — $/M input | $4.00 | $0.13 |
| Price — $/M output | $20.00 | $0.44 |
| Inputs | text, image, file | text, image, video |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 100% | 94% |
| APEX | 74% | 53% |
| ARC-AGI | 99% | 91% |
| ARC-AGI-2 | 93% | 66% |
| GPQA Diamond | 91% | 90% |
| Humanity's Last Exam | 61% | 40% |
| SciCode | 67% | 52% |
| SimpleQA Verified | 72% | 32% |
| WebDev Arena | 1820 | 1607 |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is Claude Opus 5.5 better than GLM-5.3-Flash?
On Epoch AI's Capabilities Index, Claude Opus 5.5 scores higher (167) than GLM-5.3-Flash (153). The right pick depends on your task, so compare their coding, math, and reasoning scores in the table above.
Which is cheaper, Claude Opus 5.5 or GLM-5.3-Flash?
GLM-5.3-Flash is cheaper on input tokens at $0.13 per million, versus $4.00 (representative OpenRouter pricing).
Which has a larger context window, Claude Opus 5.5 or GLM-5.3-Flash?
Neither: both support up to 1M tokens.
Which is better for coding, Claude Opus 5.5 or GLM-5.3-Flash?
Claude Opus 5.5 ranks higher across coding benchmarks like WebDev Arena and SciCode: 100th vs 75th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.