Gemini 2.5 Flash vs Solar Pro 4
Updated October 21, 2026. 38 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick Gemini 2.5 Flash for coding: it scores 28.7 on the Vibe Coding Index against 24.4 for Solar Pro 4.
Pick Solar Pro 4 when output tokens cost 4.2x less, or when what matters is LMArena Text: coding or LMArena Text: software and IT, where it leads.
- Shared results
- 38
- Gemini 2.5 Flash only
- 31
- Solar Pro 4 only
- 7
- Like-for-like categories
- 7 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, four public coding benchmarks
Gemini 2.5 Flash
Gemini 2.5 Flash scores 28.7 against 24.4.
One benchmark behind each score
Intelligence
AA Intelligence Index
Solar Pro 4
Solar Pro 4 leads, 28.2 against 15.5.
Same board, both measured
Web design
Design Arena: websites
Solar Pro 4
Solar Pro 4 leads, 1176 against 1074.
Same board, both measured
Long documents
Listed context window
Gemini 2.5 Flash
Gemini 2.5 Flash takes 1.05M tokens against 524K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Solar Pro 4
Gemini 2.5 Flash $0.0015, Solar Pro 4 $0.0004 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 2.5 Flash has the number, $0.466.
Directional only
At a glance
- Coding index
- Gemini 2.5 Flash 28.7 from 1 benchmark, Solar Pro 4 24.4 from 1 benchmark.
- Widest category
- Web design, 16.9 points apart on average over 6 shared benchmarks.
- Widest single gap
- Design Arena: game dev: Gemini 2.5 Flash 1005 against Solar Pro 4 1170, 20.6 points apart on a 0 to 100 scale.
- Output price
- Gemini 2.5 Flash $2.50 against Solar Pro 4 $0.60 per million output tokens, 4.2x apart.
- Context window
- Gemini 2.5 Flash takes 1.05M tokens, Solar Pro 4 524K.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Gemini 2.5 Flash | Bars | Solar Pro 4 | Ties |
|---|---|---|---|---|
| Coding | 0 | 2 | ||
| Intelligence | 0 | 1 | ||
| Reasoning | 1 | 4 | ||
| Math | 0 | 2 | ||
| Knowledge | 4 | 0 | ||
| Web design | 0 | 6 | ||
| General | 17 | 1 | ||
| All shared boards | 22 | 16 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index02
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| SWE-bench Verified | 28.7% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena WebDev | Not measured | 1371 | Only Solar Pro 4 measured |
| AA Coding Index | Not measured | 52.7 | Only Solar Pro 4 measured |
| LiveCodeBench (Artificial Analysis run) | 69.5% | Not measured | Only Gemini 2.5 Flash measured |
| SciCode | Not measured | 48.0% | Only Solar Pro 4 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 13.6% | Not measured | Only Gemini 2.5 Flash measured |
| Terminal-Bench | 17.1% | Not measured | Only Gemini 2.5 Flash measured |
| ALE-Bench | Not measured | 179.3 | Only Solar Pro 4 measured |
| LMArena Text: coding | 1423 | 1438 | Solar Pro 4 |
| LMArena Text: software and IT | 1425 | 1431 | Solar Pro 4 |
| LMArena WebDev: React | Not measured | 1363 | Only Solar Pro 4 measured |
| LMArena WebDev: HTML | Not measured | 1371 | Only Solar Pro 4 measured |
| Neither model has a result on the other 26 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| AA Intelligence Index | 15.5 | 28.2 | Solar Pro 4 |
| Epoch Capabilities Index | 142.9 | Not measured | Only Gemini 2.5 Flash measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | Not measured | 1105 | Only Solar Pro 4 measured |
| τ²-Bench Telecom | 31.6% | Not measured | Only Gemini 2.5 Flash measured |
| BALROG | 33.5% | Not measured | Only Gemini 2.5 Flash measured |
| Vending-Bench 2 | $549 | Not measured | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 35 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index14
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | 79.0% | 89.1% | Solar Pro 4 |
| Humanity's Last Exam (Artificial Analysis run) | 12.1% | 29.8% | Solar Pro 4 |
| ARC-AGI | 33.3% | Not measured | Only Gemini 2.5 Flash measured |
| ARC-AGI-2 | 2.5% | Not measured | Only Gemini 2.5 Flash measured |
| SimpleBench | 41.2% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text: hard prompts | 1422 | 1400 | Gemini 2.5 Flash |
| LMArena Text: expert | 1426 | 1428 | Solar Pro 4 |
| LMArena Text: hard prompts in English | 1420 | 1427 | Solar Pro 4 |
| LMArena Vision: diagrams | 1245 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Vision: homework | 1244 | Not measured | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 11 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| AA Math Index | 73.3 | Not measured | Only Gemini 2.5 Flash measured |
| AIME 2025 (Artificial Analysis run) | 73.3% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text: math | 1411 | 1421 | Solar Pro 4 |
| LMArena Text: mathematical work | 1422 | 1427 | Solar Pro 4 |
| Neither model has a result on the other 9 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| MedCode (Vals AI) | 40.4% | Not measured | Only Gemini 2.5 Flash measured |
| MMLU Pro (Artificial Analysis run) | 83.2% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text: science | 1433 | 1404 | Gemini 2.5 Flash |
| LMArena Text: medicine and healthcare | 1428 | 1374 | Gemini 2.5 Flash |
| LMArena Text: legal and government | 1430 | 1383 | Gemini 2.5 Flash |
| LMArena Text: business and finance | 1404 | 1381 | Gemini 2.5 Flash |
| Neither model has a result on the other 11 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| Design Arena: websites | 1074 | 1176 | Solar Pro 4 |
| Design Arena: UI components | 1005 | 1150 | Solar Pro 4 |
| Design Arena: game dev | 1005 | 1170 | Solar Pro 4 |
| Design Arena: data viz | 1060 | 1177 | Solar Pro 4 |
| Design Arena: 3D | 1021 | 1178 | Solar Pro 4 |
| Design Arena: all code categories | 1059 | 1182 | Solar Pro 4 |
| Design Arena: SVG | 1018 | Not measured | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 2 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index171
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 44.8% | Not measured | Only Gemini 2.5 Flash measured |
| MedScribe (Vals AI) | 83.0% | Not measured | Only Gemini 2.5 Flash measured |
| IFBench | 50.3% | Not measured | Only Gemini 2.5 Flash measured |
| Long context reasoning (AA-LCR) | 65.3% | 70.7% | Solar Pro 4 |
| DTBench | 76.5% | Not measured | Only Gemini 2.5 Flash measured |
| LMCA | 27.5% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text | 1417 | 1388 | Gemini 2.5 Flash |
| LMArena Text: instruction following | 1405 | 1375 | Gemini 2.5 Flash |
| LMArena Text: creative writing | 1400 | 1317 | Gemini 2.5 Flash |
| LMArena Vision | 1235 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text: English | 1418 | 1414 | Gemini 2.5 Flash |
| LMArena Text: non-English | 1409 | 1363 | Gemini 2.5 Flash |
| LMArena Text: Chinese | 1449 | 1422 | Gemini 2.5 Flash |
| LMArena Text: German | 1417 | 1358 | Gemini 2.5 Flash |
| LMArena Text: Japanese | 1396 | 1320 | Gemini 2.5 Flash |
| LMArena Text: Korean | 1385 | 1383 | Gemini 2.5 Flash |
| LMArena Text: French | 1432 | 1400 | Gemini 2.5 Flash |
| LMArena Text: Spanish | 1422 | 1409 | Gemini 2.5 Flash |
| LMArena Text: Russian | 1415 | 1357 | Gemini 2.5 Flash |
| LMArena Text: Polish | 1413 | 1304 | Gemini 2.5 Flash |
| LMArena Text: multi-turn | 1408 | 1385 | Gemini 2.5 Flash |
| LMArena Text: longer queries | 1419 | 1382 | Gemini 2.5 Flash |
| LMArena Text: writing and language | 1405 | 1344 | Gemini 2.5 Flash |
| LMArena Text: entertainment and media | 1393 | 1332 | Gemini 2.5 Flash |
| LMArena Vision: English | 1239 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Vision: Chinese | 1284 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Vision: reading text | 1237 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Vision: humor | 1225 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Vision: captioning | 1277 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Vision: recognizing things | 1252 | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Vision: creative writing | 1241 | Not measured | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 2.5 Flash | Solar Pro 4 | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Solar Pro 4 costs less
Repository review
50K input + 3K output tokens
Solar Pro 4 costs less
Agent loop
200K input + 10K output tokens
Solar Pro 4 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Google Gemini 2.5 Flash | Upstage Solar Pro 4 |
|---|---|---|
| Maker | Upstage | |
| Weights | No public weights listed | No public weights listed |
| Released | June 17, 2025 | August 10, 2026 |
| Context window | 1.05M | 524K |
| Input $/Mtok | $0.30 | $0.15 |
| Output $/Mtok | $2.50 | $0.60 |
| Coding index | 28.7 | 24.4 |
| Independent measurements behind it | 1 | 1 |
| Cost per solved task | $0.466 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 2.5 Flash better than Solar Pro 4 for coding?
Pick Gemini 2.5 Flash for coding: it scores 28.7 on the Vibe Coding Index against 24.4 for Solar Pro 4. Pick Solar Pro 4 when output tokens cost 4.2x less, or when what matters is LMArena Text: coding or LMArena Text: software and IT, where it leads.
Which is cheaper, Gemini 2.5 Flash or Solar Pro 4?
Gemini 2.5 Flash costs $0.30 per million input tokens and $2.50 per million output tokens; Solar Pro 4 costs $0.15 and $0.60. Cost per solved task is known for Gemini 2.5 Flash only.
Which has the bigger context window, Gemini 2.5 Flash or Solar Pro 4?
Gemini 2.5 Flash, with 1.05M tokens against 524K.
How many benchmarks is the Gemini 2.5 Flash vs Solar Pro 4 comparison based on?
38 benchmarks have a result for both models as of October 21, 2026. Gemini 2.5 Flash's coding index rests on 1 independent benchmark and Solar Pro 4's on 1. Where only one model has a result, the page says so instead of naming a winner.