text model comparison
Claude Sonnet 5 vs GLM-5.3-Flash
Claude Sonnet 5 and GLM-5.3-Flash are both current text models, from Anthropic and Z.ai. GLM-5.3-Flash is 93% cheaper per 1M input tokens than Claude Sonnet 5, $0.15 vs $2. On Arena Text, Claude Sonnet 5 scores 1461 Elo and GLM-5.3-Flash 1475 Elo (Arena, measured October 8, 2026). Both accept 1,000,000 tokens of context.
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 | Claude Sonnet 5 | GLM-5.3-Flash |
|---|---|---|
| Price per 1M input tokens | $2 | $0.15 (better) |
| Price per 1M output tokens | $10 | $0.50 (better) |
| Cost of 10M input and 2M output tokens | $40 | $2.50 (better) |
| Arena Text | 1461 Elo (#30 of 49) | 1475 Elo (#21 of 49) (better) |
| GPQA Diamond | 90.5% (#25 of 40) (better) | 90.2% (#27 of 40) |
| FrontierMath Tiers 1-3 (v2) | 65.6% (#25 of 40) (better) | 55.8% (#31 of 40) |
| SimpleQA Verified | 33.7% (#29 of 36) | Not measured |
| LiveBench Overall | 74.85 points (#4 of 5) | Not measured |
| Provider | Anthropic | Z.ai |
| Release date | June 30, 2026 | August 26, 2026 |
| Access | API only | API and open weights |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Input | text | text, image, video |
| Output | text | text |
Scores:Arena · 2026-10-12Epoch AI · 2026-10-12LiveBench · 2026-06-25
When to choose each
Claude Sonnet 5
Best for
- Agentic coding evaluations with current introductory API pricing
Watch out for
- The launch price is introductory through 2026-08-31; refresh pricing before evaluating workloads after that date
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
Claude Sonnet 5 vs GLM-5.3-Flash FAQ
Which is cheaper, Claude Sonnet 5 or GLM-5.3-Flash?
GLM-5.3-Flash is 93% cheaper per 1M input tokens than Claude Sonnet 5, $0.15 vs $2. For 10M input and 2M output tokens, Claude Sonnet 5 costs $40 and GLM-5.3-Flash $2.50 at standard rates.
Which scores higher on independent benchmarks, Claude Sonnet 5 or GLM-5.3-Flash?
GLM-5.3-Flash leads on Arena Text, 1475 Elo to 1461 Elo; Claude Sonnet 5 leads on GPQA Diamond, 90.5% to 90.2%; Claude Sonnet 5 leads on FrontierMath Tiers 1-3 (v2), 65.6% to 55.8%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, Claude Sonnet 5 or GLM-5.3-Flash?
Both accept 1,000,000 tokens of context.
Can I run Claude Sonnet 5 or GLM-5.3-Flash myself?
GLM-5.3-Flash is released as open weights you can run yourself; Claude Sonnet 5 is available through its provider's API only.
Related comparisons
Production evaluation
Choosing between Claude Sonnet 5 and GLM-5.3-Flash?
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