Gemini 3.1 Flash Lite vs o3 Pro
Updated October 21, 2026. 5 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Neither model has a coding score yet, so the two cannot be ranked on coding.
Gemini 3.1 Flash Lite has the edge where output tokens cost 53.3x less, and where the context window is larger, 1.05M against 200K tokens.
- Shared results
- 5
- Gemini 3.1 Flash Lite only
- 10
- o3 Pro only
- 6
- 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, six public coding benchmarks
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
No call
Only o3 Pro has a AA Intelligence Index result, 21.9.
Directional only
Long documents
Listed context window
Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite $0.0010, o3 Pro $0.060 per turn.
List prices
At a glance
- Coding index
- Gemini 3.1 Flash Lite not benchmarked, o3 Pro not benchmarked.
- Widest category
- General, 6.8 points apart on average over 2 shared benchmarks.
- Widest single gap
- DTBench: Gemini 3.1 Flash Lite 76.8% against o3 Pro 86.9%, 10.1 points apart on a 0 to 100 scale.
- Output price
- Gemini 3.1 Flash Lite $1.50 against o3 Pro $80.00 per million output tokens, 53.3x apart.
- Context window
- Gemini 3.1 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 3.1 Flash Lite | Bars | o3 Pro | Ties |
|---|---|---|---|---|
| Coding | 0 | 1 | ||
| Intelligence | 0 | 1 | ||
| Reasoning | 0 | 1 | ||
| General | 0 | 2 | ||
| All shared boards | 0 | 5 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index01
| Benchmark | Gemini 3.1 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 84.9% | Only o3 Pro measured |
| SciCode | 43.4% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Terminal-Bench Hard (Artificial Analysis run) | 24.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| WeirdML | 52.2% | 58.2% | o3 Pro |
| Neither model has a result on the other 34 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Gemini 3.1 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 21.9 | Only o3 Pro measured |
| Epoch Capabilities Index | 144.3 | 147.3 | o3 Pro |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| τ²-Bench Telecom | 31.3% | Not measured | Only Gemini 3.1 Flash Lite measured |
| DeepResearch Bench | 37.3% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Neither model has a result on the other 37 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Gemini 3.1 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | 82.2% | 84.5% | o3 Pro |
| Humanity's Last Exam (Artificial Analysis run) | 17.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| GPQA Diamond (Epoch AI run) | 81.8% | Not measured | Only Gemini 3.1 Flash Lite measured |
| ARC-AGI | Not measured | 59.3% | Only o3 Pro measured |
| ARC-AGI-2 | Not measured | 4.9% | Only o3 Pro measured |
| Neither model has a result on the other 16 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| OTIS Mock AIME | 80.0% | Not measured | Only Gemini 3.1 Flash Lite measured |
| FrontierMath, tiers 1 to 3 | 27.7% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Neither model has a result on the other 11 boards here | |||
KnowledgeNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 17 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 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 3.1 Flash Lite | o3 Pro | Leader |
|---|---|---|---|
| IFBench | 77.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Long context reasoning (AA-LCR) | 74.3% | Not measured | Only Gemini 3.1 Flash Lite measured |
| DTBench | 76.8% | 86.9% | o3 Pro |
| LMCA | 35.0% | 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 |
| Neither model has a result on the other 40 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 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 3.1 Flash Lite costs less
Repository review
50K input + 3K output tokens
Gemini 3.1 Flash Lite costs less
Agent loop
200K input + 10K output tokens
Gemini 3.1 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 3.1 Flash Lite | OpenAI o3 Pro |
|---|---|---|
| Maker | OpenAI | |
| Weights | No public weights listed | No public weights listed |
| Released | May 7, 2026 | June 10, 2025 |
| Context window | 1.05M | 200K |
| Input $/Mtok | $0.25 | $20.00 |
| Output $/Mtok | $1.50 | $80.00 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3.1 Flash Lite better than o3 Pro for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Gemini 3.1 Flash Lite has the edge where output tokens cost 53.3x less, and where the context window is larger, 1.05M against 200K tokens.
Which is cheaper, Gemini 3.1 Flash Lite or o3 Pro?
Gemini 3.1 Flash Lite costs $0.25 per million input tokens and $1.50 per million output tokens; o3 Pro costs $20.00 and $80.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Gemini 3.1 Flash Lite or o3 Pro?
Gemini 3.1 Flash Lite, with 1.05M tokens against 200K.
How many benchmarks is the Gemini 3.1 Flash Lite vs o3 Pro comparison based on?
5 benchmarks have a result for both models as of October 21, 2026. Gemini 3.1 Flash Lite's coding index rests on 0 independent benchmarks and o3 Pro's on 0. Where only one model has a result, the page says so instead of naming a winner.