Claude 3.5 SonnetvsGLM-5.1
Claude 3.5 Sonnet | GLM-5.1 | |
|---|---|---|
| Specifications | ||
ParametersA rough measure of how big the model is. More parameters usually means more capable and more expensive to run, though it is a poor guide on its own — a smaller, newer model often beats a larger, older one. | — | 744B |
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view. | — | 200k |
| API pricingUSD per 1M tokens · lower wins | ||
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it. | — | $1.40 |
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one. | — | $4.40 |
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again. | — | $0.26 |
| Benchmarks | ||
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 45% | 22% |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 59.4% | 86.2% |
| BenchmarksPublished by one model only | ||
SWE-Bench VerifiedCoding — Real coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 33.4% | — |
Next.js EvalsNext.js coding — Vercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | — | 75% |
Terminal-Bench 2.0Agentic terminal coding — Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? (Version 2.0 of the test.) Higher is better. | — | 63.5% |
BrowseCompWeb browsing — Can the AI browse the web and track down hard-to-find answers? Higher is better. | — | 68% |
Humanity's Last Exam · with toolsMultidisciplinary reasoning — Humanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better. | — | 52.3% |
Arena Elo (Text)Community preference — Real people chat with two anonymous AIs side by side and vote for the answer they prefer. Votes become a chess-style Elo rating on arena.ai — it measures which AI people actually like, not test scores. Higher is better. | — | 1468 |
Arena Elo (Code)Community preference (code) — Like the text arena, but people vote on which AI writes better code. The votes become a chess-style Elo rating on arena.ai. Higher is better. | — | 1510 |
| Overview | ||
| Company | Anthropic | Z.ai |
| Release date | Jun 20 2024 | Apr 7 2026 |
| Access | Proprietary | Open Weight |
Frequently asked questions
Claude 3.5 Sonnet and GLM-5.1 are evenly matched across the 2 benchmarks they both report (BullshitBench v2, GPQA Diamond). Only GLM-5.1 has a verified first-party API price: $1.40 per million input tokens and $4.40 per million output tokens. No pay-as-you-go API rate is tracked for Claude 3.5 Sonnet. Claude 3.5 Sonnet shipped 656 days before GLM-5.1, so benchmark comparisons should account for the intervening progress.
Claude 3.5 Sonnet is proprietary, while GLM-5.1 is open weight.
On BullshitBench v2, Claude 3.5 Sonnet leads at 45% vs GLM-5.1 at 22%. On GPQA Diamond, GLM-5.1 leads at 86.2% vs Claude 3.5 Sonnet at 59.4%.
Claude 3.5 Sonnet was released by Anthropic on Jun 20 2024.
GLM-5.1 was released by Z.ai on Apr 7 2026.
GLM-5.1 leads on GPQA Diamond — Claude 3.5 Sonnet 59.4% vs GLM-5.1 86.2%.
Only GLM-5.1 has a verified first-party API price: $1.40 per million input tokens and $4.40 per million output tokens. No pay-as-you-go API rate is tracked for Claude 3.5 Sonnet. Rates are pay-as-you-go API prices verified on August 18, 2026.
Claude 3.5 Sonnet is a proprietary model released by Anthropic. GLM-5.1 is an open weight model released by Z.ai.