Compare / Gemini 3.8 Flash vs Kimi K3.1 Pro
Gemini 3.8 Flash vs Kimi K3.1 Pro
Which is cheaper, which is more capable, and which does better at each kind of work, from 60 results on 4 sources that measured both models.
GoogleGemini 3.8 Flash
Moonshot AIKimi K3.1 Pro
Gemini 3.8 Flash wins 209 too close to callKimi K3.1 Pro wins 31
Of the 60 results both models have, the better value on each. Results whose reported ranges overlap are too close to call.
Results as of 4 November 2026 (catalogue release 2026-11-04-56cfea57899a). See also Google vs Moonshot AI, every model from both labs.
Gemini 3.8 Flash or Kimi K3.1 Pro? The short answer
They score about the same, so pick Gemini 3.8 Flash: it costs 4.4 times less per product listing on CatalogBench.
- Spring Prompt overall: Gemini 3.8 Flash 59, Kimi K3.1 Pro 56 (out of 100; how the score works).
- Gemini 3.8 Flash is cheaper to run: $0.010 against $0.045 per product listing on CatalogBench (4.4 times less).
- On our own benchmarks, on the results both models have: Gemini 3.8 Flash does better for speed under pressure; Kimi K3.1 Pro for decks from an analysis and marketing planning.
Head to head
59
Spring Prompt overall
56
$3.00
Price per million tokens, blendedlower is better
$4.00
1,048,576
Context window, tokens
1,048,576
Every fact side by side
| Gemini 3.8 Flash | Kimi K3.1 Pro | |
|---|---|---|
| Price per million tokens | $1.50 in · $7.50 out | $2.00 in · $10.00 out |
| Blended (3 in : 1 out) | $3.00 | $4.00 |
| Cheapest host, blended | $1.50 (Google) | $4.00 (Moonshot AI, MXFP4) |
| Cost per product listing (CatalogBench) | $0.010 | $0.045 |
| Intelligence Index | 40.9 | – |
| Spring Prompt overall | 59 | 56 |
| Output speed, tokens a second | 141 | – |
| Context window | 1,048,576 tokens | 1,048,576 tokens |
| Released | 2 Sep 2026 | – |
| Weights | Closed | Open |
| Developer based in | the US | China |
Prices are the developer's list price where we have read it, otherwise the typical host on OpenRouter; see every model's price. Intelligence and speed from Artificial Analysis.
Which is better for what
Each model's rank among the models on sale today, for each kind of work, from our own benchmarks and licensed sources. Further right is better; the better rank is in green.
Product listingsTurning a sparse product feed and photos into listings that can go live
16 of 25
not measured
Decks from an analysisTurning a finished analysis into a deck you could present as it is
19 of 26
11 of 26
User surveysPlanning a user survey and reading its results without being misled
not measured
13 of 15
Marketing planningPlanning a year of ad spend without overspending
9 of 26
3 of 26
Agents and tool useMulti-step tasks with tools: support desks, coding agents, function calls
34 of 160
not measured
Professional workReal tasks from banking, consulting and law, business documents and freelance projects
11 of 51
not measured
Reasoning and knowledgeHard questions across science, maths and general knowledge
14 of 188
not measured
WritingWhat people prefer in blind comparisons, and judged writing quality
3 of 173
not measured
Sticking to the factsSummarising without inventing things, and factual answers
12 of 143
not measured
Speed under pressureGood decisions against a real clock (fast chess)
8 of 29
22 of 29
Their slides, side by side
The same brief for both: Manchester store investment review for Hearthside Coffee, an invented company. First slide of each deck from DeckBench.
From our research
- DeepSeek-V4.1-Flash-1017 review: better at analysis, much worse at sticking to the product data 19 Oct 2026
- AI Checkpoint: Argon matches Opus, until it sells 16 Oct 2026
- Gemini 4 Argon review: Opus-level product data at a quarter of the cost, until you ask it to sell 14 Oct 2026
- We Told 11 AI Models What Happened in 2026. Most of Them Thought We Were Making It Up. 12 Oct 2026
Every shared result
Each model's best result on every measure both have, grouped by benchmark, with the setting that produced it. Under each measure, every model that benchmark has measured is a grey tick, best to the right, so you can see where the two sit in the field. The headline measures of each benchmark come first; the rest are under "Show all". Green marks the better value; where a source reports ranges that overlap, neither is marked.
| Measure | Gemini 3.8 Flash | Kimi K3.1 Pro |
|---|---|---|
| BulletBench measured by Spring Prompt · 3 results | ||
| Cost per game · Bullet 60sUS dollars, lower is better 21 · 25 of 34 measured | $0.0154 | $0.0175low reasoning |
| Ladder Elo · Bullet 60sladder Elo, higher is better 1 · 28 of 34 measured | 1,068low reasoning | 147low reasoning |
| Games lost on time · Bullet 60s% of games, lower is better 20 · 30 of 34 measured | 50.0%low reasoning | 87.5%low reasoning |
| CatalogBench measured by Spring Prompt · 3 results | ||
| Cost per productUS dollars, lower is better 14 · 24 of 26 measured | $0.0103 | $0.0454 |
| Channel compliance% of products, higher is better 18 · 1 of 26 measured | 99.4% | 100.0% |
| Channel rules broken% of products, lower is better 13 · 1 of 26 measured | 0.6% | 0.0% |
| DeckBench measured by Spring Prompt · 3 results | ||
| Cost per deckUS dollars, lower is better 12 · 24 of 26 measured | $0.0613 | $0.54 |
| Deck ratingrating, higher is betterThe rating weighs each win by how strong the other deck was; the win rate counts wins against whichever decks a model happened to meet, so the two can disagree. 19 · 11 of 26 measured | 824 | 1,259 |
| Accurate decks% of tasks, higher is better 19 · 7 of 26 measured | 16.7% | 66.7% |
| ROASBench measured by Spring Prompt · 3 results | ||
| Overall scorescore out of 100, higher is better 9 · 3 of 26 measured | 51.4 | 55.1 |
| Audience scorescore out of 100, higher is better 9 · 7 of 26 measured | 67.1 | 67.6 |
| Business scorescore out of 100, higher is better 9 · 2 of 26 measured | 51.0 | 58.2 |
Show all 60 results (48 more)
| Measure | Gemini 3.8 Flash | Kimi K3.1 Pro |
|---|---|---|
| BulletBench measured by Spring Prompt · 2 results | ||
| Invalid moves · Bullet 60s% of moves, lower is better 1 · 1 of 34 measured | 0.0% | 0.0%low reasoning |
| Median move time · Bullet 60smilliseconds, lower is better 25 · 34 of 34 measured | 1.8 slow reasoning | 5.0 slow reasoning |
| CatalogBench measured by Spring Prompt · 26 results | ||
| Channel rules broken · sales brief% of products, lower is better 14 · 1 of 26 measured | 0.6% | 0.0% |
| Claims to check% of products, lower is better 1 · 1 of 26 measured | 0.0% | 0.0% |
| Claims to check · sales brief% of products, lower is better 21 · 1 of 26 measured | 5.4% | 0.0% |
| Conflicts caught% of conflicts, higher is better 1 · 1 of 26 measured | 100.0% | 100.0% |
| Content quality% of checks, higher is better 8 · 1 of 26 measured | 97.7% | 98.9% |
| Content quality · sales brief% of checks, higher is better 10 · 20 of 26 measured | 97.6% | 95.3% |
| Decision accuracy% of decisions, higher is better 14 · 1 of 26 measured | 96.4% | 98.9% |
| Failed outputs% of products, lower is better 1 · 1 of 26 measured | 0.0% | 0.0% |
| Failed outputs · sales brief% of products, lower is better 1 · 24 of 26 measured | 0.0% | 3.6% |
| Field accuracy% of missing fields, higher is better 18 · 2 of 26 measured | 92.7% | 95.6% |
| Invented values% of filled values, lower is better 2 · 18 of 26 measured | 0.3% | 2.1% |
| Missing UK information% of products, lower is better 1 · 1 of 26 measured | 0.0% | 0.0% |
| Missing UK information · sales brief% of products, lower is better 1 · 1 of 26 measured | 0.0% | 0.0% |
| Not findable% of products, lower is better 20 · 12 of 26 measured | 8.3% | 5.4% |
| Not findable · sales brief% of products, lower is better 21 · 10 of 26 measured | 8.9% | 3.6% |
| Publish-ready listings% of products, higher is better 16 · 1 of 26 measured | 54.8% | 78.6% |
| Publish-ready listings · sales brief% of products, higher is better 18 · 2 of 26 measured | 16.7% | 75.0% |
| Time per productseconds, lower is better 17 · 26 of 26 measured | 18.7 | 114 |
| Unsupported claims% of products, lower is better 17 · 1 of 26 measured | 31.6% | 0.0% |
| Unsupported claimsclaims per product, lower is better 16 · 1 of 26 measured | 0.79 | 0.00 |
| Unsupported claims · sales brief% of products, lower is better 21 · 1 of 26 measured | 81.6% | 1.8% |
| Unsupported claims · sales briefclaims per product, lower is better 18 · 5 of 26 measured | 3.08 | 0.21 |
| Wrong attributes% of products, lower is better 7 · 11 of 26 measured | 15.5% | 16.1% |
| Wrong attributes · sales brief% of products, lower is better 2 · 4 of 26 measured | 11.9% | 14.3% |
| Wrong category or variant% of products, lower is better 20 · 5 of 26 measured | 3.6% | 1.8% |
| Wrong category or variant · sales brief% of products, lower is better 17 · 23 of 26 measured | 3.0% | 5.4% |
| DeckBench measured by Spring Prompt · 14 results | ||
| Caveat dropped% of tasks, lower is better 1 · 13 of 26 measured | 0.0% | 16.7% |
| Clean layout% of tasks, higher is better 21 · 24 of 26 measured | 16.7% | 0.0% |
| Design quality% of the maximum, higher is better 15 · 3 of 26 measured | 61.7% | 83.9% |
| Draft figure quoted% of tasks, lower is better 21 · 1 of 26 measured | 50.0% | 0.0% |
| Findings missing% of tasks, lower is better 1 · 24 of 26 measured | 0.0% | 33.3% |
| Head-to-head win rate% of comparisons, higher is betterThe rating weighs each win by how strong the other deck was; the win rate counts wins against whichever decks a model happened to meet, so the two can disagree. 20 · 9 of 26 measured | 40.3% | 75.6% |
| Layout defects% of tasks, lower is better 21 · 24 of 26 measured | 83.3% | 100.0% |
| Misleading metric used% of tasks, lower is better 1 · 1 of 26 measured | 0.0% | 0.0% |
| Presentable decks% of tasks, higher is better 13 · 13 of 26 measured | 0.0% | 0.0% |
| Recommendation late or wrong% of tasks, lower is better 15 · 1 of 26 measured | 33.3% | 0.0% |
| Slides needing work% of tasks, lower is better 8 · 1 of 26 measured | 33.3% | 0.0% |
| Time per deckseconds, lower is better 12 · 26 of 26 measured | 93.0 | 1,288 |
| Unsupported claims% of tasks, lower is better 23 · 1 of 26 measured | 50.0% | 0.0% |
| Unsupported numbers% of tasks, lower is better 22 · 1 of 26 measured | 16.7% | 0.0% |
| ROASBench measured by Spring Prompt · 6 results | ||
| Consistency scorescore out of 100, higher is better 4 · 5 of 26 measured | 36.4 | 36.3 |
| Contribution profitsimulated US dollars, higher is better 4 · 3 of 26 measured | $842,432 | $858,023 |
| Cost of a runUS dollars, lower is better 12 · 25 of 26 measured | $0.16 | $1.60 |
| Months over budgetmonths of 12, lower is better 1 · 1 of 26 measured | 0 | 0 |
| Planning scorescore out of 100, higher is better 17 · 4 of 26 measured | 54.7 | 55.0 |
| Return on ad spendprofit per $1 spent, higher is better 8 · 1 of 26 measured | $0.65 | $0.72 |
Compare them with other models
- Google vs Moonshot AIEvery model from both labs, best against best
- Gemini 3.8 Flash vs Claude Opus 5.5Most intelligent at $3–10 per million tokens
- Gemini 3.8 Flash vs DeepSeek-V4.1-FlashFastest with similar intelligence
- Kimi K3.1 Pro vs Claude Opus 5.5Highest-scoring overall at $3–10 per million tokens
- Kimi K3.1 Pro vs Kimi K3Moonshot AI's best other model
Quick answers
Is Gemini 3.8 Flash better than Kimi K3.1 Pro?
They score about the same, so pick Gemini 3.8 Flash: it costs 4.4 times less per product listing on CatalogBench.
Which is cheaper, Gemini 3.8 Flash or Kimi K3.1 Pro?
Gemini 3.8 Flash is cheaper to run: $0.010 against $0.045 per product listing on CatalogBench (4.4 times less).
Which is better for decks from an analysis, Gemini 3.8 Flash or Kimi K3.1 Pro?
Kimi K3.1 Pro ranks 11 of 26 models on sale for turning a finished analysis into a deck you could present as it is, against 19 for Gemini 3.8 Flash.
Which is better for marketing planning, Gemini 3.8 Flash or Kimi K3.1 Pro?
Kimi K3.1 Pro ranks 3 of 26 models on sale for planning a year of ad spend without overspending, against 9 for Gemini 3.8 Flash.
Which is better for speed under pressure, Gemini 3.8 Flash or Kimi K3.1 Pro?
Gemini 3.8 Flash ranks 8 of 29 models on sale for good decisions against a real clock (fast chess), against 22 for Kimi K3.1 Pro.
Run Gemini 3.8 Flash and Kimi K3.1 Pro on your own prompt
Benchmarks aren't your data. Try both side by side in the playground, with the cost of every answer.