Solar Pro 3 vs Solar Pro 4
Too close to call on our weighted score (Solar Pro 4 55, Solar Pro 3 55). The right pick depends on what you value most.
Upstage
Solar Pro 3
55/100- ECI—
- Price$0.25 / $0.25
- Context131K
Upstage
Solar Pro 4
55/100- ECI—
- Price$0.30 / $1.20
- Context524K
Add a model
Make it a three-way comparison.
Too close to call
It is close. Our weighted score puts them within a point (Solar Pro 4 55/100, Solar Pro 3 55/100), so choose by what matters most for your work: Solar Pro 3 on price and Solar Pro 4 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 3Solar Pro 3 $0.25 · Solar Pro 4 $0.525 per 1M tokens (3:1 blend)
- Longest contextSolar Pro 4Solar Pro 4 524,288 · Solar Pro 3 131,072 tokens
- Widest inputsSame inputsSolar Pro 3: Text · Solar Pro 4: Text
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Solar Pro 3 | Solar Pro 4 |
|---|---|---|---|
| Price | 50% | 78 | 63 |
| Inputs & features | 30% | 35 | 45 |
| Context window | 20% | 24 | 49 |
| Overall | 100% | 55/100 | 55/100 |
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 3Upstage | Solar Pro 4Upstage |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.25 (best) | $0.30 |
| Output | $0.25 (best) | $1.20 |
| Cached input | — | $0.06 |
| Blended (3:1) | $0.25 (best) | $0.525 |
| Long-context rate | Same rate | Same rate |
| Price source | Official Upstage API | Official Upstage API |
| Limits | ||
| Context window | 131,072 tokens | 524,288 tokens (best) |
| Max output | 8,192 tokens | 131,072 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | No |
| PDFs | No | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yeslow · medium · high | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes |
| Structured output | No | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | solar-pro3 | solar-pro4 |
| API providers | 2 | 3 (best) |
| Released | Jan 2026 | Aug 6, 2026 |
| Knowledge cutoff | Mar 2025 | Feb 2026 |
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 3$3.00
- Solar Pro 4$5.40
Which should you choose?
Which is better: Solar Pro 3 or Solar Pro 4?
It is close. Our weighted score puts them within a point (Solar Pro 4 55/100, Solar Pro 3 55/100), so choose by what matters most for your work: Solar Pro 3 on price and Solar Pro 4 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 3 or Solar Pro 4?
Solar Pro 3 is cheaper at $0.25 input / $0.25 output per million tokens (official Upstage API price). Solar Pro 4 costs $0.30 input / $1.20 output per million tokens (official Upstage API price). At a typical mix of three input tokens to one output token, that is $0.25 per million tokens for Solar Pro 3 versus $0.525 for Solar Pro 4 (2.1× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Solar Pro 3 has not been scored yet and Solar Pro 4 has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Solar Pro 3 and Solar Pro 4 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?
Solar Pro 4 has the largest context window at 524,288 tokens, against 131,072 for Solar Pro 3. Maximum output per response: Solar Pro 3 up to 8,192, Solar Pro 4 up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Solar Pro 3 accepts text; Solar Pro 4 accepts text. They handle the same number of input types.
Are any of these open source?
No. Solar Pro 3 and Solar Pro 4 are proprietary and only available through APIs and apps.
Which is newer?
Solar Pro 4 is the newest, released Aug 6, 2026. Solar Pro 3 came out Jan 2026. Knowledge cutoff: Solar Pro 3 Mar 2025, Solar Pro 4 Feb 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 Oct 4, 2026.
