Gemini 3.1 Flash Lite vs Mercury 2.5
Mercury 2.5 costs 10.0x less per output token than Gemini 3.1 Flash Lite ($0.15 vs $1.50 per million). Updated October 22, 2026; 3 benchmarks have a result for both.
Gemini 3.1 Flash Lite or Mercury 2.5: which to pick
Only Mercury 2.5 has a coding score, 1.6 on the Vibe Coding Index; Gemini 3.1 Flash Lite has none, so the two cannot be ranked on coding.
Pick Gemini 3.1 Flash Lite for a larger context window (1.05M against 260K tokens) and work measured by SciCode or Humanity's Last Exam (Artificial Analysis run), where it leads.
- Shared results
- 3
- Gemini 3.1 Flash Lite only
- 13
- Mercury 2.5 only
- 19
- 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
Only Mercury 2.5 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Mercury 2.5 has a AA Intelligence Index result, 12.3.
Directional only
Long documents
Listed context window
Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite takes 1.05M tokens against 260K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 2.5
Gemini 3.1 Flash Lite $0.0010, Mercury 2.5 $0.0001 per turn.
List prices
At a glance
- Coding index
- Gemini 3.1 Flash Lite not benchmarked, Mercury 2.5 1.6 from 2 benchmarks.
- Widest category
- Reasoning, 5.4 points apart on average over 1 shared benchmark.
- Widest single gap
- Humanity's Last Exam (Artificial Analysis run): Gemini 3.1 Flash Lite 17.2% against Mercury 2.5 11.8%, 5.4 points apart on a 0 to 100 scale.
- Output price
- Gemini 3.1 Flash Lite $1.50 against Mercury 2.5 $0.15 per million output tokens, 10.0x apart.
- Context window
- Gemini 3.1 Flash Lite takes 1.05M tokens, Mercury 2.5 260K.
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 | Mercury 2.5 | Ties |
|---|---|---|---|---|
| Coding | 1 | 0 | ||
| Reasoning | 1 | 0 | ||
| General | 1 | 0 | ||
| All shared boards | 3 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index10
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | Leader |
|---|---|---|---|
| Terminal-Bench 4 (Vals AI) | Not measured | 0.0% | Only Mercury 2.5 measured |
| Vibe Code Bench (Vals AI) | Not measured | 3.7% | Only Mercury 2.5 measured |
| Code migration (Vals AI) | Not measured | 4.5% | Only Mercury 2.5 measured |
| IOI (Vals AI) | Not measured | 2.4% | Only Mercury 2.5 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 34.5% | Only Mercury 2.5 measured |
| SkillsBench (Vals AI) | Not measured | 18.1% | Only Mercury 2.5 measured |
| CyberBench (Vals AI) | Not measured | 45.5% | Only Mercury 2.5 measured |
| SciCode | 43.4% | 38.5% | Gemini 3.1 Flash Lite |
| Terminal-Bench Hard (Artificial Analysis run) | 24.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| WeirdML | 52.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| ALE-Bench | Not measured | 301.6 | Only Mercury 2.5 measured |
| Neither model has a result on the other 28 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 12.3 | Only Mercury 2.5 measured |
| Epoch Capabilities Index | 144.3 | Not measured | Only Gemini 3.1 Flash Lite measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | Leader |
|---|---|---|---|
| Finance Agent (Vals AI) | Not measured | 18.9% | Only Mercury 2.5 measured |
| Tax Agent Bench (Vals AI) | Not measured | 2.5% | Only Mercury 2.5 measured |
| Legal Research Bench (Vals AI) | Not measured | 4.3% | Only Mercury 2.5 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 8.8% | Only Mercury 2.5 measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 0.0% | Only Mercury 2.5 measured |
| 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 34 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | 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% | 11.8% | Gemini 3.1 Flash Lite |
| GPQA Diamond (Epoch AI run) | 81.8% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Kagi LLM Benchmark | 67.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Neither model has a result on the other 18 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index3 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | 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 |
| ProofBench | Not measured | 3.0% | Only Mercury 2.5 measured |
| Neither model has a result on the other 10 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | Leader |
|---|---|---|---|
| LegalBench (Vals AI) | Not measured | 83.1% | Only Mercury 2.5 measured |
| MedCode (Vals AI) | Not measured | 31.3% | Only Mercury 2.5 measured |
| Neither model has a result on the other 16 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | Leader |
|---|---|---|---|
| Public Benefits Bench (Vals AI) | Not measured | 45.3% | Only Mercury 2.5 measured |
| MedScribe (Vals AI) | Not measured | 55.1% | Only Mercury 2.5 measured |
| IFBench | 77.2% | Not measured | Only Gemini 3.1 Flash Lite measured |
| Long context reasoning (AA-LCR) | 74.3% | 71.7% | Gemini 3.1 Flash Lite |
| 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 40 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite | Mercury 2.5 | 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
Mercury 2.5 costs less
Repository review
50K input + 3K output tokens
Mercury 2.5 costs less
Agent loop
200K input + 10K output tokens
Mercury 2.5 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 | Inception Mercury 2.5 |
|---|---|---|
| Maker | Inception | |
| Weights | No public weights listed | No public weights listed |
| Released | May 7, 2026 | September 8, 2026 |
| Context window | 1.05M | 260K |
| Input $/Mtok | $0.25 | $0.04 |
| Output $/Mtok | $1.50 | $0.15 |
| Coding index | Not benchmarked | 1.6 |
| Independent measurements behind it | 0 | 2 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3.1 Flash Lite better than Mercury 2.5 for coding?
Only Mercury 2.5 has a coding score, 1.6 on the Vibe Coding Index; Gemini 3.1 Flash Lite has none, so the two cannot be ranked on coding. Pick Gemini 3.1 Flash Lite for a larger context window (1.05M against 260K tokens) and work measured by SciCode or Humanity's Last Exam (Artificial Analysis run), where it leads.
Which is cheaper, Gemini 3.1 Flash Lite or Mercury 2.5?
Gemini 3.1 Flash Lite costs $0.25 per million input tokens and $1.50 per million output tokens; Mercury 2.5 costs $0.04 and $0.15. Cost per solved task is known for neither of them.
Which has the bigger context window, Gemini 3.1 Flash Lite or Mercury 2.5?
Gemini 3.1 Flash Lite, with 1.05M tokens against 260K.
How many benchmarks is the Gemini 3.1 Flash Lite vs Mercury 2.5 comparison based on?
3 benchmarks have a result for both models as of October 22, 2026. Gemini 3.1 Flash Lite's coding index rests on 0 independent benchmarks and Mercury 2.5's on 2. Where only one model has a result, the page says so instead of naming a winner.