Solar Pro 2 vs GLM-4.5-Air
Too close to call on our weighted score (Solar Pro 2 51, GLM-4.5-Air 48). The right pick depends on what you value most.
UpstageSolar Pro 2
51/100- ECI—
- Price$0.25 / $0.25
- Context66K
Z.ai (Zhipu)GLM-4.5-Air
48/100- ECI—
- Price$0.20 / $1.10
- Context131K
Add a model
Make it a three-way comparison.
Too close to call
It is close. Our weighted score puts them within 3 points (Solar Pro 2 51/100, GLM-4.5-Air 48/100), so choose by what matters most for your work: Solar Pro 2 on price and GLM-4.5-Air for long inputs. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceSolar Pro 2Solar Pro 2 $0.25 · GLM-4.5-Air $0.425 per 1M tokens (3:1 blend)
- Longest contextGLM-4.5-AirGLM-4.5-Air 131,072 · Solar Pro 2 65,536 tokens
- Widest inputsSame inputsSolar Pro 2: Text · GLM-4.5-Air: Text
- Self-hostingGLM-4.5-AirPublishes downloadable weights
| Measure | Weight | Solar Pro 2 | GLM-4.5-Air |
|---|---|---|---|
| Price | 50% | 75 | 65 |
| Inputs & features | 30% | 35 | 35 |
| Context window | 20% | 12 | 25 |
| Overall | 100% | 51/100 | 48/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Solar Pro 2Upstage | GLM-4.5-AirZ.ai (Zhipu) |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.25 | $0.20 (best) |
| Output | $0.25 (best) | $1.10 |
| Cached input | — | $0.03 |
| Blended (3:1) | $0.25 (best) | $0.425 |
| Long-context rate | Same rate | Same rate |
| Price source | Official Upstage API | Official Z.AI API |
| Limits | ||
| Context window | 65,536 tokens | 131,072 tokens (best) |
| Max output | 8,192 tokens | 98,304 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | No |
| PDFs | No | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yesminimal · high | Yes |
| Tool calling | Yes | Yes |
| Structured output | No | No |
| Availability | ||
| Weights | Proprietary | Open |
| API model ID | solar-pro2 | glm-4.5-air |
| API providers | 2 | 19 (best) |
| Released | May 20, 2025 | Jul 28, 2025 |
| Knowledge cutoff | Mar 2025 | Apr 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Solar Pro 2$3.00
- GLM-4.5-Air$4.20
Which should you choose?
Which is better: Solar Pro 2 or GLM-4.5-Air?
It is close. Our weighted score puts them within 3 points (Solar Pro 2 51/100, GLM-4.5-Air 48/100), so choose by what matters most for your work: Solar Pro 2 on price and GLM-4.5-Air for long inputs. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Solar Pro 2 or GLM-4.5-Air?
Solar Pro 2 is cheaper at $0.25 input / $0.25 output per million tokens (official Upstage API price). GLM-4.5-Air costs $0.20 input / $1.10 output per million tokens (official Z.AI API price). At a typical mix of three input tokens to one output token, that is $0.25 per million tokens for Solar Pro 2 versus $0.425 for GLM-4.5-Air (1.7× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Solar Pro 2 has not been scored yet and GLM-4.5-Air has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Solar Pro 2 and GLM-4.5-Air yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
GLM-4.5-Air has the largest context window at 131,072 tokens, against 65,536 for Solar Pro 2. Maximum output per response: Solar Pro 2 up to 8,192, GLM-4.5-Air up to 98,304 tokens.
Which can read images, PDFs, audio or video?
Solar Pro 2 accepts text; GLM-4.5-Air accepts text. They handle the same number of input types.
Are any of these open source?
GLM-4.5-Air publishes its weights and can be self-hosted; Solar Pro 2 is proprietary.
Which is newer?
GLM-4.5-Air is the newest, released Jul 28, 2025. Solar Pro 2 came out May 20, 2025. Knowledge cutoff: Solar Pro 2 Mar 2025, GLM-4.5-Air Apr 2025.
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.
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