Gemini 3.1 Flash Lite vs GPT-5 Pro
Gemini 3.1 Flash Lite costs 80.0x less per output token than GPT-5 Pro ($1.50 vs $120.00 per million). Updated October 21, 2026; 3 benchmarks have a result for both.
Gemini 3.1 Flash Lite or GPT-5 Pro: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Gemini 3.1 Flash Lite for output tokens 80.0x cheaper ($1.50 vs $120.00 per million) and a larger context window (1.05M against 400K tokens).
- Shared results
- 3
- Gemini 3.1 Flash Lite only
- 12
- GPT-5 Pro only
- 5
- Like-for-like categories
- 3 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
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
Long documents
Listed context window
Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite $0.0010, GPT-5 Pro $0.075 per turn.
List prices
At a glance
- Coding index
- Gemini 3.1 Flash Lite not benchmarked, GPT-5 Pro not benchmarked.
- Widest category
- Math, 28.1 points apart on average over 1 shared benchmark.
- Widest single gap
- FrontierMath, tiers 1 to 3: Gemini 3.1 Flash Lite 27.7% against GPT-5 Pro 55.8%, 28.1 points apart on a 0 to 100 scale.
- Output price
- Gemini 3.1 Flash Lite $1.50 against GPT-5 Pro $120.00 per million output tokens, 80.0x apart.
- Context window
- Gemini 3.1 Flash Lite takes 1.05M tokens, GPT-5 Pro 400K.
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 | GPT-5 Pro | Ties |
|---|---|---|---|---|
| Coding | 0 | 1 | ||
| Intelligence | 0 | 1 | ||
| Math | 0 | 1 | ||
| All shared boards | 0 | 3 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index01
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 Pro | Leader |
|---|---|---|---|
| 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% | 60.4% | GPT-5 Pro |
| Neither model has a result on the other 35 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 Pro | Leader |
|---|---|---|---|
| Epoch Capabilities Index | 144.3 | 150.6 | GPT-5 Pro |
| Neither model has a result on the other 1 board here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 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 | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 Pro | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | 82.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| 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 | 70.2% | Only GPT-5 Pro measured |
| ARC-AGI-2 | Not measured | 18.3% | Only GPT-5 Pro measured |
| SimpleBench | Not measured | 61.6% | Only GPT-5 Pro measured |
| Chess puzzles | Not measured | 48.0% | Only GPT-5 Pro measured |
| Neither model has a result on the other 14 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 Pro | Leader |
|---|---|---|---|
| OTIS Mock AIME | 80.0% | Not measured | Only Gemini 3.1 Flash Lite measured |
| FrontierMath, tiers 1 to 3 | 27.7% | 55.8% | GPT-5 Pro |
| FrontierMath, tier 4 | Not measured | 19.5% | Only GPT-5 Pro measured |
| Neither model has a result on the other 10 boards here | |||
KnowledgeNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 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 | GPT-5 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 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% | Not measured | Only Gemini 3.1 Flash Lite measured |
| LMCA | 35.0% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Neither model has a result on the other 42 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | GPT-5 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 GPT-5 Pro |
|---|---|---|
| Maker | OpenAI | |
| Weights | No public weights listed | No public weights listed |
| Released | May 7, 2026 | October 6, 2025 |
| Context window | 1.05M | 400K |
| Input $/Mtok | $0.25 | $15.00 |
| Output $/Mtok | $1.50 | $120.00 |
| 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 GPT-5 Pro for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Gemini 3.1 Flash Lite for output tokens 80.0x cheaper ($1.50 vs $120.00 per million) and a larger context window (1.05M against 400K tokens).
Which is cheaper, Gemini 3.1 Flash Lite or GPT-5 Pro?
Gemini 3.1 Flash Lite costs $0.25 per million input tokens and $1.50 per million output tokens; GPT-5 Pro costs $15.00 and $120.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Gemini 3.1 Flash Lite or GPT-5 Pro?
Gemini 3.1 Flash Lite, with 1.05M tokens against 400K.
How many benchmarks is the Gemini 3.1 Flash Lite vs GPT-5 Pro comparison based on?
3 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 GPT-5 Pro's on 0. Where only one model has a result, the page says so instead of naming a winner.