DeepSeek V3.1 vs Gemini 3 Flash Preview
Updated October 21, 2026. 7 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Only Gemini 3 Flash Preview has a coding score, 43.7 on the Vibe Coding Index; DeepSeek V3.1 has none, so the two cannot be ranked on coding.
DeepSeek V3.1 has the edge where output tokens cost 2.0x less.
- Shared results
- 7
- DeepSeek V3.1 only
- 3
- Gemini 3 Flash Preview only
- 62
- Like-for-like categories
- 3 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
Only Gemini 3 Flash Preview has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 26.3 against 13.7.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Gemini 3 Flash Preview has a GPQA Diamond result, 87.9%.
Directional only
Math
AIME
No call
Only Gemini 3 Flash Preview has a AIME result, 95.6%.
Directional only
Knowledge
MMLU Pro
No call
Only Gemini 3 Flash Preview has a MMLU Pro result, 88.6%.
Directional only
Web design
Design Arena: websites
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 1196 against 1123.
Same board, both measured
Long documents
Listed context window
Gemini 3 Flash Preview
Gemini 3 Flash Preview takes 1.05M tokens against 164K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
DeepSeek V3.1
DeepSeek V3.1 $0.0013, Gemini 3 Flash Preview $0.0020 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 3 Flash Preview has the number, $0.37.
Directional only
At a glance
- Coding index
- DeepSeek V3.1 not benchmarked, Gemini 3 Flash Preview 43.7 from 2 benchmarks.
- Widest category
- General, 12.6 points apart on average over 2 shared benchmarks.
- Widest single gap
- LMCA: DeepSeek V3.1 24.3% against Gemini 3 Flash Preview 43.1%, 18.8 points apart on a 0 to 100 scale.
- Output price
- DeepSeek V3.1 $1.50 against Gemini 3 Flash Preview $3.00 per million output tokens, 2.0x apart.
- Context window
- DeepSeek V3.1 takes 164K tokens, Gemini 3 Flash Preview 1.05M.
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 | DeepSeek V3.1 | Bars | Gemini 3 Flash Preview | Ties |
|---|---|---|---|---|
| Intelligence | 0 | 1 | ||
| Web design | 0 | 4 | ||
| General | 0 | 2 | ||
| All shared boards | 0 | 7 |
CodingDirectional onlySix of these boards feed the Vibe Coding Index13 boards, none shared
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 75.8% | Only Gemini 3 Flash Preview measured |
| LiveCodeBench (Vals AI) | Not measured | 85.6% | Only Gemini 3 Flash Preview measured |
| SWE-bench Verified (Vals AI) | Not measured | 75.0% | Only Gemini 3 Flash Preview measured |
| Vibe Code Bench (Vals AI) | Not measured | 20.2% | Only Gemini 3 Flash Preview measured |
| Code migration (Vals AI) | Not measured | 6.4% | Only Gemini 3 Flash Preview measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Gemini 3 Flash Preview measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 53.9% | Only Gemini 3 Flash Preview measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 90.8% | Only Gemini 3 Flash Preview measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 38.6% | Only Gemini 3 Flash Preview measured |
| Terminal-Bench | Not measured | 64.3% | Only Gemini 3 Flash Preview measured |
| GSO-Bench | Not measured | 9.8% | Only Gemini 3 Flash Preview measured |
| WeirdML | Not measured | 61.6% | Only Gemini 3 Flash Preview measured |
| ALE-Bench | Not measured | 1367.2 | Only Gemini 3 Flash Preview measured |
| Neither model has a result on the other 25 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 13.7 | 26.3 | Gemini 3 Flash Preview |
| Neither model has a result on the other 1 board here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index14 boards, none shared
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | Not measured | 1110 | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building full-stack apps | Not measured | 1063 | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building mobile apps | Not measured | 1090 | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building Android apps | Not measured | 1057 | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building Godot games | Not measured | 1161 | Only Gemini 3 Flash Preview measured |
| Design Arena: PowerPoint slides | Not measured | 1036 | Only Gemini 3 Flash Preview measured |
| Finance Agent (Vals AI) | Not measured | 42.5% | Only Gemini 3 Flash Preview measured |
| Tax Agent Bench (Vals AI) | Not measured | 11.8% | Only Gemini 3 Flash Preview measured |
| Legal Research Bench (Vals AI) | Not measured | 18.3% | Only Gemini 3 Flash Preview measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 26.0% | Only Gemini 3 Flash Preview measured |
| τ²-Bench Telecom | Not measured | 80.4% | Only Gemini 3 Flash Preview measured |
| BALROG | Not measured | 48.1% | Only Gemini 3 Flash Preview measured |
| DeepResearch Bench | Not measured | 49.8% | Only Gemini 3 Flash Preview measured |
| Vending-Bench 2 | Not measured | $3,635 | Only Gemini 3 Flash Preview measured |
| Neither model has a result on the other 25 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index11 boards, none shared
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 87.9% | Only Gemini 3 Flash Preview measured |
| MMMU Pro (Vals AI) | Not measured | 87.6% | Only Gemini 3 Flash Preview measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 89.8% | Only Gemini 3 Flash Preview measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 36.6% | Only Gemini 3 Flash Preview measured |
| GPQA Diamond (Epoch AI run) | Not measured | 89.4% | Only Gemini 3 Flash Preview measured |
| ARC-AGI | Not measured | 84.7% | Only Gemini 3 Flash Preview measured |
| ARC-AGI-2 | Not measured | 33.6% | Only Gemini 3 Flash Preview measured |
| SimpleBench | Not measured | 61.1% | Only Gemini 3 Flash Preview measured |
| Chess puzzles | Not measured | 39.0% | Only Gemini 3 Flash Preview measured |
| Mystery game puzzles | Not measured | 26.0% | Only Gemini 3 Flash Preview measured |
| VPCT | Not measured | 72.6% | Only Gemini 3 Flash Preview measured |
| Neither model has a result on the other 10 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| AIME | Not measured | 95.6% | Only Gemini 3 Flash Preview measured |
| MGSM (Vals AI) | Not measured | 93.3% | Only Gemini 3 Flash Preview measured |
| AA Math Index | Not measured | 97.0 | Only Gemini 3 Flash Preview measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 97.0% | Only Gemini 3 Flash Preview measured |
| OTIS Mock AIME | Not measured | 95.6% | Only Gemini 3 Flash Preview measured |
| FrontierMath, tiers 1 to 3 | Not measured | 51.2% | Only Gemini 3 Flash Preview measured |
| FrontierMath, tier 4 | Not measured | 17.1% | Only Gemini 3 Flash Preview measured |
| ProofBench | Not measured | 15.0% | Only Gemini 3 Flash Preview measured |
| Neither model has a result on the other 5 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index11 boards, none shared
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 88.6% | Only Gemini 3 Flash Preview measured |
| LegalBench (Vals AI) | Not measured | 86.9% | Only Gemini 3 Flash Preview measured |
| CaseLaw (Vals AI) | Not measured | 55.8% | Only Gemini 3 Flash Preview measured |
| CorpFin (Vals AI) | Not measured | 66.4% | Only Gemini 3 Flash Preview measured |
| TaxEval (Vals AI) | Not measured | 73.9% | Only Gemini 3 Flash Preview measured |
| MortgageTax (Vals AI) | Not measured | 68.7% | Only Gemini 3 Flash Preview measured |
| MedQA (Vals AI) | Not measured | 95.8% | Only Gemini 3 Flash Preview measured |
| MedCode (Vals AI) | Not measured | 55.9% | Only Gemini 3 Flash Preview measured |
| MMLU Pro (Artificial Analysis run) | Not measured | 89.0% | Only Gemini 3 Flash Preview measured |
| SimpleQA Verified | Not measured | 66.8% | Only Gemini 3 Flash Preview measured |
| GeoBench | Not measured | 88.0% | Only Gemini 3 Flash Preview measured |
| Neither model has a result on the other 6 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1123 | 1196 | Gemini 3 Flash Preview |
| Design Arena: UI components | 1085 | Not measured | Only DeepSeek V3.1 measured |
| Design Arena: game dev | 1084 | 1166 | Gemini 3 Flash Preview |
| Design Arena: data viz | 1095 | Not measured | Only DeepSeek V3.1 measured |
| Design Arena: 3D | 1077 | 1184 | Gemini 3 Flash Preview |
| Design Arena: all code categories | 1112 | 1189 | Gemini 3 Flash Preview |
| Design Arena: SVG | 967 | Not measured | Only DeepSeek V3.1 measured |
| Neither model has a result on the other 2 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| SAGE (Vals AI) | Not measured | 51.8% | Only Gemini 3 Flash Preview measured |
| MedScribe (Vals AI) | Not measured | 69.9% | Only Gemini 3 Flash Preview measured |
| Vals Multimodal Index | Not measured | 52.2% | Only Gemini 3 Flash Preview measured |
| IFBench | Not measured | 78.0% | Only Gemini 3 Flash Preview measured |
| Long context reasoning (AA-LCR) | Not measured | 78.0% | Only Gemini 3 Flash Preview measured |
| DTBench | 82.7% | 89.1% | Gemini 3 Flash Preview |
| LMCA | 24.3% | 43.1% | Gemini 3 Flash Preview |
| Neither model has a result on the other 39 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | DeepSeek V3.1 | Gemini 3 Flash Preview | 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
DeepSeek V3.1 costs less
Repository review
50K input + 3K output tokens
DeepSeek V3.1 costs less
Agent loop
200K input + 10K output tokens
DeepSeek V3.1 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 | DeepSeek V3.1 | Google Gemini 3 Flash Preview |
|---|---|---|
| Maker | DeepSeek | |
| Weights | Open weights | No public weights listed |
| Released | August 21, 2025 | December 17, 2025 |
| Context window | 164K | 1.05M |
| Input $/Mtok | $0.55 | $0.50 |
| Output $/Mtok | $1.50 | $3.00 |
| Coding index | Not benchmarked | 43.7 |
| Independent measurements behind it | 0 | 2 |
| Cost per solved task | Not computable | $0.37 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is DeepSeek V3.1 better than Gemini 3 Flash Preview for coding?
Only Gemini 3 Flash Preview has a coding score, 43.7 on the Vibe Coding Index; DeepSeek V3.1 has none, so the two cannot be ranked on coding. DeepSeek V3.1 has the edge where output tokens cost 2.0x less.
Which is cheaper, DeepSeek V3.1 or Gemini 3 Flash Preview?
DeepSeek V3.1 costs $0.55 per million input tokens and $1.50 per million output tokens; Gemini 3 Flash Preview costs $0.50 and $3.00. Cost per solved task is known for Gemini 3 Flash Preview only.
Which has the bigger context window, DeepSeek V3.1 or Gemini 3 Flash Preview?
Gemini 3 Flash Preview, with 1.05M tokens against 164K.
How many benchmarks is the DeepSeek V3.1 vs Gemini 3 Flash Preview comparison based on?
7 benchmarks have a result for both models as of October 21, 2026. DeepSeek V3.1's coding index rests on 0 independent benchmarks and Gemini 3 Flash Preview's on 2. Where only one model has a result, the page says so instead of naming a winner.