GPT-6.1 Terra vs GLM-5.3 vs Claude Sonnet 5.5
GPT-6.1 Terra comes out ahead, 76 to 72 and 63 on our weighted score, and it is the cheaper option too.
- Our pick
OpenAIGPT-6.1 Terra
76/100- ECI168.1
- Price$1.00 / $5.00
- Context1.05M
Z.ai (Zhipu)GLM-5.3
63/100- ECI156.2
- Price$1.40 / $4.40
- Context1M
AnthropicClaude Sonnet 5.5
72/100- ECI166.7
- Price$2.00 / $10.00
- Context1M
GPT-6.1 Terra is our pick
GPT-6.1 Terra is the better all-round choice, scoring 76/100 against Claude Sonnet 5.5 (72) and GLM-5.3 (63). It leads on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-6.1 TerraCapabilities Index (ECI): GPT-6.1 Terra 168.1 · Claude Sonnet 5.5 166.7 · GLM-5.3 156.2
- Lowest priceGPT-6.1 TerraGPT-6.1 Terra $2.00 · GLM-5.3 $2.15 · Claude Sonnet 5.5 $4.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6.1 TerraGPT-6.1 Terra 1,050,000 · GLM-5.3 1,000,000 · Claude Sonnet 5.5 1,000,000 tokens
- Widest inputsGPT-6.1 Terra and Claude Sonnet 5.5GPT-6.1 Terra: Text, Images, PDFs · GLM-5.3: Text · Claude Sonnet 5.5: Text, Images, PDFs
- Self-hostingGLM-5.3Publishes downloadable weights
| Measure | Weight | GPT-6.1 Terra | GLM-5.3 | Claude Sonnet 5.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 99 | 84 | 97 |
| Price | 25% | 34 | 33 | 20 |
| Inputs & features | 15% | 80 | 45 | 80 |
| Context window | 10% | 61 | 60 | 60 |
| Overall | 100% | 76/100 | 63/100 | 72/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-6.1 TerraOpenAI | GLM-5.3Z.ai (Zhipu) | Claude Sonnet 5.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 168.1 (best) | 156.2 | 166.7 |
| ECI rank | #3 of 165 (best) | #33 of 165 | #5 of 165 |
| GPQA DiamondGraduate-level science questions | 94.3% | 90.9% | 95.6% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 90.9% (best) | 68.8% | 88.8% |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | 91.1% | 100% (best) |
| SimpleQA VerifiedShort factual questions | 57.3% (best) | 41.0% | 46.5% |
| Price per million tokens | |||
| Input | $1.00 (best) | $1.40 | $2.00 |
| Output | $5.00 | $4.40 (best) | $10.00 |
| Cached input | $0.05 (best) | $0.26 | $0.10 |
| Blended (3:1) | $2.00 (best) | $2.15 | $4.00 |
| Long-context rate | Over 272K: $2.00 / $7.50 | Same rate | Same rate |
| Price source | Official OpenAI API | Official Z.AI API | Official Anthropic API |
| Limits | |||
| Context window | 1,050,000 tokens (best) | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 131,072 tokens (best) | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | No | Yes |
| PDFs | Yes | No | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · high · max | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | gpt-6.1-terra | glm-5.3 | claude-sonnet-5-5 |
| API providers | 22 | 83 (best) | 34 |
| Released | Oct 26, 2026 | Aug 14, 2026 | Sep 28, 2026 |
| Knowledge cutoff | Jun 1, 2026 | — | Jun 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-6.1 Terra$20.00
- GLM-5.3$22.80
- Claude Sonnet 5.5$40.00
Which should you choose?
Which is better: GPT-6.1 Terra, GLM-5.3 or Claude Sonnet 5.5?
GPT-6.1 Terra is the better all-round choice, scoring 76/100 against Claude Sonnet 5.5 (72) and GLM-5.3 (63). It leads on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-6.1 Terra, GLM-5.3 or Claude Sonnet 5.5?
GPT-6.1 Terra is cheaper at $1.00 input / $5.00 output per million tokens (official OpenAI API price). GLM-5.3 costs $1.40 input / $4.40 output per million tokens (official Z.AI API price); Claude Sonnet 5.5 costs $2.00 input / $10.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for GPT-6.1 Terra versus $2.15 for GLM-5.3 (1.1× as much) and $4.00 for Claude Sonnet 5.5 (2× as much).
Which scores higher on benchmarks?
GPT-6.1 Terra scores higher on the Capabilities Index (ECI): GPT-6.1 Terra 168.1 (#3 of 165), Claude Sonnet 5.5 166.7 (#5 of 165) and GLM-5.3 156.2 (#33 of 165). The confidence ranges of the top two overlap (164.9–172.9 vs 163.6–171.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — Claude Sonnet 5.5 95.6%, GPT-6.1 Terra 94.3%, GLM-5.3 90.9%; FrontierMath Tiers 1–3 — GPT-6.1 Terra 90.9%, Claude Sonnet 5.5 88.8%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — GPT-6.1 Terra 100%, Claude Sonnet 5.5 100%, GLM-5.3 91.1%; SimpleQA Verified — GPT-6.1 Terra 57.3%, Claude Sonnet 5.5 46.5%, GLM-5.3 41.0%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-6.1 Terra, GLM-5.3 and Claude Sonnet 5.5 yet, so there is no like-for-like coding score. On overall capability, GPT-6.1 Terra leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
GPT-6.1 Terra has the largest context window at 1,050,000 tokens, against 1,000,000 for GLM-5.3 and 1,000,000 for Claude Sonnet 5.5. Maximum output per response: GPT-6.1 Terra up to 128,000, GLM-5.3 up to 131,072, Claude Sonnet 5.5 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GPT-6.1 Terra accepts text, images and PDFs; GLM-5.3 accepts text; Claude Sonnet 5.5 accepts text, images and PDFs. GPT-6.1 Terra handles the widest range of inputs.
Are any of these open source?
GLM-5.3 publishes its weights and can be self-hosted; GPT-6.1 Terra and Claude Sonnet 5.5 is proprietary.
Which is newer?
GPT-6.1 Terra is the newest, released Oct 26, 2026. Claude Sonnet 5.5 came out Sep 28, 2026; GLM-5.3 came out Aug 14, 2026. Knowledge cutoff: GPT-6.1 Terra Jun 1, 2026, Claude Sonnet 5.5 Jun 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
