Solar Pro 4 vs Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite comes out ahead, 73 to 55 on our weighted score, though Solar Pro 4 is 7% cheaper per token.
Upstage
Solar Pro 4
55/100- ECI—
- Price$0.30 / $1.20
- Context524K
- Our pick
GoogleGemini 3.1 Flash Lite
73/100- ECI—
- Price$0.25 / $1.50
- Context1.05M
Add a model
Make it a three-way comparison.
Gemini 3.1 Flash Lite is our pick
Gemini 3.1 Flash Lite is the better all-round choice, scoring 73/100 against Solar Pro 4 (55). It leads on inputs & features and context window. 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 4Solar Pro 4 $0.525 · Gemini 3.1 Flash Lite $0.563 per 1M tokens (3:1 blend)
- Longest contextGemini 3.1 Flash LiteGemini 3.1 Flash Lite 1,048,576 · Solar Pro 4 524,288 tokens
- Widest inputsGemini 3.1 Flash LiteSolar Pro 4: Text · Gemini 3.1 Flash Lite: Text, Images, PDFs, Audio, Video
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Solar Pro 4 | Gemini 3.1 Flash Lite |
|---|---|---|---|
| Price | 50% | 63 | 62 |
| Inputs & features | 30% | 45 | 100 |
| Context window | 20% | 49 | 61 |
| Overall | 100% | 55/100 | 73/100 |
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 4Upstage | Gemini 3.1 Flash LiteGoogle |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.30 | $0.25 (best) |
| Output | $1.20 (best) | $1.50 |
| Cached input | $0.06 | $0.025 (best) |
| Blended (3:1) | $0.525 (best) | $0.563 |
| Long-context rate | Same rate | Same rate |
| Price source | Official Upstage API | Official Google API |
| Limits | ||
| Context window | 524,288 tokens | 1,048,576 tokens (best) |
| Max output | 131,072 tokens (best) | 65,536 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | Yes |
| PDFs | No | Yes |
| Audio | No | Yes |
| Video | No | Yes |
| Reasoning | Yesminimal · low · medium · high · xhigh · max | Yesminimal · low · medium · high |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | solar-pro4 | gemini-3.1-flash-lite |
| API providers | 3 | 23 (best) |
| Released | Aug 6, 2026 | May 7, 2026 |
| Knowledge cutoff | Feb 2026 | Jan 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 4$5.40
- Gemini 3.1 Flash Lite$5.50
Which should you choose?
Which is better: Solar Pro 4 or Gemini 3.1 Flash Lite?
Gemini 3.1 Flash Lite is the better all-round choice, scoring 73/100 against Solar Pro 4 (55). It leads on inputs & features and context window. 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 4 or Gemini 3.1 Flash Lite?
Solar Pro 4 is cheaper at $0.30 input / $1.20 output per million tokens (official Upstage API price). Gemini 3.1 Flash Lite costs $0.25 input / $1.50 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $0.525 per million tokens for Solar Pro 4 versus $0.563 for Gemini 3.1 Flash Lite (1.1× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Solar Pro 4 has not been scored yet and Gemini 3.1 Flash Lite has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Solar Pro 4 and Gemini 3.1 Flash Lite 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?
Gemini 3.1 Flash Lite has the largest context window at 1,048,576 tokens, against 524,288 for Solar Pro 4. Maximum output per response: Solar Pro 4 up to 131,072, Gemini 3.1 Flash Lite up to 65,536 tokens.
Which can read images, PDFs, audio or video?
Solar Pro 4 accepts text; Gemini 3.1 Flash Lite accepts text, images, PDFs, audio and video. Gemini 3.1 Flash Lite handles the widest range of inputs.
Are any of these open source?
No. Solar Pro 4 and Gemini 3.1 Flash Lite are proprietary and only available through APIs and apps.
Which is newer?
Solar Pro 4 is the newest, released Aug 6, 2026. Gemini 3.1 Flash Lite came out May 7, 2026. Knowledge cutoff: Solar Pro 4 Feb 2026, Gemini 3.1 Flash Lite Jan 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 Oct 4, 2026.
