Gemini 3.5 Flash Lite vs o3 Pro
Updated October 21, 2026. 8 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick o3 Pro for coding: it scores 84.9 on the Vibe Coding Index against 33.6 for Gemini 3.5 Flash Lite.
Pick Gemini 3.5 Flash Lite when output tokens cost 32.0x less, or when the context window is larger, 1.05M against 200K tokens.
- Shared results
- 8
- Gemini 3.5 Flash Lite only
- 75
- o3 Pro only
- 3
- Like-for-like categories
- 4 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
o3 Pro
o3 Pro scores 84.9 against 33.6.
One benchmark behind each score
Intelligence
AA Intelligence Index
Gemini 3.5 Flash Lite
Gemini 3.5 Flash Lite leads, 22.2 against 21.9.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Gemini 3.5 Flash Lite has a AA Agentic Index result, 14.3.
Directional only
Reasoning
GPQA Diamond
No call
Only Gemini 3.5 Flash Lite has a GPQA Diamond result, 83.8%.
Directional only
Knowledge
MMLU Pro
No call
Only Gemini 3.5 Flash Lite has a MMLU Pro result, 85.8%.
Directional only
Long documents
Listed context window
Gemini 3.5 Flash Lite
Gemini 3.5 Flash Lite takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.5 Flash Lite
Gemini 3.5 Flash Lite $0.0015, o3 Pro $0.060 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 3.5 Flash Lite has the number, $0.41.
Directional only
At a glance
- Coding index
- Gemini 3.5 Flash Lite 33.6 from 1 benchmark, o3 Pro 84.9 from 1 benchmark.
- Widest category
- Coding, 19.2 points apart on average over 1 shared benchmark.
- Widest single gap
- WeirdML: Gemini 3.5 Flash Lite 39.0% against o3 Pro 58.2%, 19.2 points apart on a 0 to 100 scale.
- Output price
- Gemini 3.5 Flash Lite $2.50 against o3 Pro $80.00 per million output tokens, 32.0x apart.
- Context window
- Gemini 3.5 Flash Lite takes 1.05M tokens, o3 Pro 200K.
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 3.5 Flash Lite | Bars | o3 Pro | Ties |
|---|---|---|---|---|
| Coding | 0 | 1 | ||
| Intelligence | 1 | 1 | ||
| Reasoning | 1 | 2 | ||
| General | 0 | 2 | ||
| All shared boards | 2 | 6 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index01
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 84.9% | Only o3 Pro measured |
| LMArena WebDev | 1435 | Not measured | Only Gemini 3.5 Flash Lite measured |
| AA Coding Index | 49.3 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LiveCodeBench (Vals AI) | 79.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| SWE-bench Verified (Vals AI) | 75.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Vibe Code Bench (Vals AI) | 37.2% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Code migration (Vals AI) | 6.2% | Not measured | Only Gemini 3.5 Flash Lite measured |
| ProgramBench (Vals AI) | 0.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Terminal-Bench 2.1 (Vals AI) | 50.2% | Not measured | Only Gemini 3.5 Flash Lite measured |
| CyberBench (Vals AI) | 59.1% | Not measured | Only Gemini 3.5 Flash Lite measured |
| SciCode | 41.3% | Not measured | Only Gemini 3.5 Flash Lite measured |
| WeirdML | 39.0% | 58.2% | o3 Pro |
| ALE-Bench | 765.3 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: coding | 1453 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: software and IT | 1451 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena WebDev: React | 1408 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena WebDev: from an image | 1448 | Not measured | Only Gemini 3.5 Flash Lite measured |
| Neither model has a result on the other 21 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.2 | 21.9 | Gemini 3.5 Flash Lite |
| Epoch Capabilities Index | 144.9 | 147.3 | o3 Pro |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| AA Agentic Index | 14.3 | Not measured | Only Gemini 3.5 Flash Lite measured |
| Finance Agent (Vals AI) | 47.4% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Tax Agent Bench (Vals AI) | 7.2% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Legal Research Bench (Vals AI) | 13.9% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Excel Modeling Benchmark (Vals AI) | 43.2% | Not measured | Only Gemini 3.5 Flash Lite measured |
| APEX-Agents | 29.3% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Neither model has a result on the other 33 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index12
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| GPQA Diamond | 83.8% | Not measured | Only Gemini 3.5 Flash Lite measured |
| MMMU Pro (Vals AI) | 83.6% | Not measured | Only Gemini 3.5 Flash Lite measured |
| GPQA Diamond (Artificial Analysis run) | 83.8% | 84.5% | o3 Pro |
| Humanity's Last Exam (Artificial Analysis run) | 18.8% | Not measured | Only Gemini 3.5 Flash Lite measured |
| GPQA Diamond (Epoch AI run) | 83.3% | Not measured | Only Gemini 3.5 Flash Lite measured |
| ARC-AGI | 53.5% | 59.3% | o3 Pro |
| ARC-AGI-2 | 10.3% | 4.9% | Gemini 3.5 Flash Lite |
| Chess puzzles | 21.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Mystery game puzzles | 19.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: hard prompts | 1441 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: expert | 1434 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: hard prompts in English | 1440 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision: diagrams | 1284 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision: homework | 1291 | Not measured | Only Gemini 3.5 Flash Lite measured |
| Neither model has a result on the other 7 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| OTIS Mock AIME | 71.1% | Not measured | Only Gemini 3.5 Flash Lite measured |
| FrontierMath, tiers 1 to 3 | 26.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| FrontierMath, tier 4 | 0.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| ProofBench | 13.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: math | 1434 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: mathematical work | 1433 | Not measured | Only Gemini 3.5 Flash Lite measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index10 boards, none shared
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| MMLU Pro | 85.8% | Not measured | Only Gemini 3.5 Flash Lite measured |
| LegalBench (Vals AI) | 84.1% | Not measured | Only Gemini 3.5 Flash Lite measured |
| CorpFin (Vals AI) | 60.7% | Not measured | Only Gemini 3.5 Flash Lite measured |
| TaxEval (Vals AI) | 72.6% | Not measured | Only Gemini 3.5 Flash Lite measured |
| MortgageTax (Vals AI) | 68.7% | Not measured | Only Gemini 3.5 Flash Lite measured |
| MedCode (Vals AI) | 43.5% | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: science | 1451 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: medicine and healthcare | 1438 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: legal and government | 1431 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: business and finance | 1423 | Not measured | Only Gemini 3.5 Flash Lite measured |
| Neither model has a result on the other 7 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Gemini 3.5 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| Public Benefits Bench (Vals AI) | 51.8% | Not measured | Only Gemini 3.5 Flash Lite measured |
| SAGE (Vals AI) | 47.3% | Not measured | Only Gemini 3.5 Flash Lite measured |
| MedScribe (Vals AI) | 70.9% | Not measured | Only Gemini 3.5 Flash Lite measured |
| Long context reasoning (AA-LCR) | 76.0% | Not measured | Only Gemini 3.5 Flash Lite measured |
| DTBench | 83.5% | 86.9% | o3 Pro |
| LMCA | 37.6% | 38.5% | o3 Pro |
| Fiction.LiveBench | Not measured | 97.2% | Only o3 Pro measured |
| Creative writing (Lech Mazur) | Not measured | 84.4% | Only o3 Pro measured |
| LMArena Text | 1435 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: instruction following | 1419 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: creative writing | 1421 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision | 1269 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: English | 1438 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: non-English | 1427 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: Chinese | 1468 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: German | 1454 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: Japanese | 1426 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: Korean | 1407 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: French | 1451 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: Spanish | 1441 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: Russian | 1443 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: Polish | 1437 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: multi-turn | 1445 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: longer queries | 1435 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: writing and language | 1428 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Text: entertainment and media | 1414 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision: English | 1269 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision: Chinese | 1311 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision: reading text | 1280 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision: humor | 1287 | Not measured | Only Gemini 3.5 Flash Lite measured |
| LMArena Vision: creative writing | 1260 | Not measured | Only Gemini 3.5 Flash Lite 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 3.5 Flash Lite | o3 Pro | 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
Gemini 3.5 Flash Lite costs less
Repository review
50K input + 3K output tokens
Gemini 3.5 Flash Lite costs less
Agent loop
200K input + 10K output tokens
Gemini 3.5 Flash Lite 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 3.5 Flash Lite | OpenAI o3 Pro |
|---|---|---|
| Maker | OpenAI | |
| Weights | No public weights listed | No public weights listed |
| Released | July 21, 2026 | June 10, 2025 |
| Context window | 1.05M | 200K |
| Input $/Mtok | $0.30 | $20.00 |
| Output $/Mtok | $2.50 | $80.00 |
| Coding index | 33.6 | 84.9 |
| Independent measurements behind it | 1 | 1 |
| Cost per solved task | $0.41 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3.5 Flash Lite better than o3 Pro for coding?
Pick o3 Pro for coding: it scores 84.9 on the Vibe Coding Index against 33.6 for Gemini 3.5 Flash Lite. Pick Gemini 3.5 Flash Lite when output tokens cost 32.0x less, or when the context window is larger, 1.05M against 200K tokens.
Which is cheaper, Gemini 3.5 Flash Lite or o3 Pro?
Gemini 3.5 Flash Lite costs $0.30 per million input tokens and $2.50 per million output tokens; o3 Pro costs $20.00 and $80.00. Cost per solved task is known for Gemini 3.5 Flash Lite only.
Which has the bigger context window, Gemini 3.5 Flash Lite or o3 Pro?
Gemini 3.5 Flash Lite, with 1.05M tokens against 200K.
How many benchmarks is the Gemini 3.5 Flash Lite vs o3 Pro comparison based on?
8 benchmarks have a result for both models as of October 21, 2026. Gemini 3.5 Flash Lite's coding index rests on 1 independent benchmark and o3 Pro's on 1. Where only one model has a result, the page says so instead of naming a winner.