Compare / Gemini 3.8 Flash vs Mercury 3
Gemini 3.8 Flash vs Mercury 3
Which is cheaper, which is more capable, and which does better at each kind of work, from 36 results on 3 sources that measured both models.
Of the 36 results both models have, the better value on each. Results whose reported ranges overlap are too close to call.
Results as of 20 October 2026 (catalogue release 2026-10-20-96eb40c3ec63).
Gemini 3.8 Flash or Mercury 3? The short answer
Pick Gemini 3.8 Flash if quality matters most: it scores higher (Spring Prompt overall 60 against 39). Pick Mercury 3 if cost matters more: it costs 5.3 times less per deck on DeckBench.
- Spring Prompt overall: Gemini 3.8 Flash 60, Mercury 3 39 (out of 100; how the score works).
- Mercury 3 is cheaper to run: $0.012 against $0.061 per deck on DeckBench (5.3 times less).
- Mercury 3 is newer: released 19 Oct 2026, against 2 Sep 2026 for Gemini 3.8 Flash.
- On our own benchmarks, on the results both models have: Gemini 3.8 Flash does better for marketing planning and speed under pressure.
Head to head
Every fact side by side
| Gemini 3.8 Flash | Mercury 3 | |
|---|---|---|
| Price per million tokens | $1.50 in · $7.50 out | $0.20 in · $0.70 out |
| Blended (3 in : 1 out) | $3.00 | $0.33 |
| Cheapest host, blended | $1.50 (Google) | – |
| Cost per deck (DeckBench) | $0.061 | $0.012 |
| Cached input, per million | – | $0.020 cached input |
| Intelligence Index | 40.9 | – |
| Spring Prompt overall | 60 | 39 |
| Output speed, tokens a second | 141 | – |
| Context window | 1,048,576 tokens | 1,000,000 tokens |
| Released | 2 Sep 2026 | 19 Oct 2026 (newer) |
| Weights | Closed | Closed |
| Developer based in | the US | the US |
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.
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 | Mercury 3 |
|---|---|---|
| BulletBench measured by Spring Prompt · 3 results | ||
| Cost per game · Bullet 60sUS dollars, lower is better 21 · 7 of 32 measured | $0.0154 | $0.0020no reasoning |
| Ladder Elo · Bullet 60sladder Elo, higher is better 1 · 15 of 32 measured | 1,068low reasoning | 491no reasoning |
| Ladder Elo · Lightning 10+1ladder Elo, higher is better 19 · 12 of 24 measured | 197low reasoning | 555no reasoning |
| DeckBench measured by Spring Prompt · 3 results | ||
| Cost per deckUS dollars, lower is better 12 · 4 of 24 measured | $0.0613 | $0.0116 |
| 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. 17 · 18 of 24 measured | 844 | 812 |
| Accurate decks% of tasks, higher is better 17 · 20 of 24 measured | 16.7% | 0.0% |
| ROASBench measured by Spring Prompt · 3 results | ||
| Overall scorescore out of 100, higher is better 7 · 18 of 24 measured | 51.4 | 26.1 |
| Audience scorescore out of 100, higher is better 7 · 21 of 24 measured | 67.1 | 43.2 |
| Business scorescore out of 100, higher is better 7 · 18 of 24 measured | 51.0 | 17.6 |
Show all 36 results (27 more)
| Measure | Gemini 3.8 Flash | Mercury 3 |
|---|---|---|
| BulletBench measured by Spring Prompt · 7 results | ||
| Cost per game · Lightning 10+1US dollars, lower is better 11 · 5 of 24 measured | $0.0041low reasoning | $0.0010no reasoning |
| Games lost on time · Bullet 60s% of games, lower is better 20 · 1 of 32 measured | 50.0%low reasoning | 0.0%no reasoning |
| Games lost on time · Lightning 10+1% of games, lower is better 21 · 1 of 24 measured | 83.3%low reasoning | 0.0%no reasoning |
| Invalid moves · Bullet 60s% of moves, lower is better 1 · 1 of 32 measured | 0.0% | 0.0%low reasoning |
| Invalid moves · Lightning 10+1% of moves, lower is better 1 · 18 of 24 measured | 0.0%low reasoning | 0.4%no reasoning |
| Median move time · Bullet 60smilliseconds, lower is better 25 · 3 of 32 measured | 1.8 slow reasoning | 0.4 sno reasoning |
| Median move time · Lightning 10+1milliseconds, lower is better 23 · 3 of 24 measured | 1.8 slow reasoning | 0.4 sno reasoning |
| DeckBench measured by Spring Prompt · 14 results | ||
| Caveat dropped% of tasks, lower is better 1 · 12 of 24 measured | 0.0% | 16.7% |
| Clean layout% of tasks, higher is better 20 · 6 of 24 measured | 16.7% | 66.7% |
| Design quality% of the maximum, higher is better 13 · 16 of 24 measured | 61.7% | 58.5% |
| Draft figure quoted% of tasks, lower is better 19 · 12 of 24 measured | 50.0% | 33.3% |
| Findings missing% of tasks, lower is better 1 · 17 of 24 measured | 0.0% | 16.7% |
| 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. 18 · 16 of 24 measured | 40.3% | 44.0% |
| Layout defects% of tasks, lower is better 20 · 6 of 24 measured | 83.3% | 33.3% |
| Misleading metric used% of tasks, lower is better 1 · 22 of 24 measured | 0.0% | 16.7% |
| Presentable decks% of tasks, higher is better 12 · 12 of 24 measured | 0.0% | 0.0% |
| Recommendation late or wrong% of tasks, lower is better 13 · 22 of 24 measured | 33.3% | 83.3% |
| Slides needing work% of tasks, lower is better 7 · 7 of 24 measured | 33.3% | 33.3% |
| Time per deckseconds, lower is better 12 · 9 of 24 measured | 93.0 | 83.3 |
| Unsupported claims% of tasks, lower is better 21 · 11 of 24 measured | 50.0% | 16.7% |
| Unsupported numbers% of tasks, lower is better 20 · 20 of 24 measured | 16.7% | 16.7% |
| ROASBench measured by Spring Prompt · 6 results | ||
| Consistency scorescore out of 100, higher is better 3 · 19 of 24 measured | 36.4 | 15.1 |
| Contribution profitsimulated US dollars, higher is better 3 · 18 of 24 measured | $842,432 | $104,868 |
| Cost of a runUS dollars, lower is better 11 · 6 of 24 measured | $0.16 | $0.0533 |
| Months over budgetmonths of 12, lower is better 1 · 1 of 24 measured | 0 | 0 |
| Planning scorescore out of 100, higher is better 15 · 23 of 24 measured | 54.7 | 53.8 |
| Return on ad spendprofit per $1 spent, higher is better 6 · 18 of 24 measured | $0.65 | $0.10 |
Compare them with other models
Quick answers
Is Gemini 3.8 Flash better than Mercury 3?
Pick Gemini 3.8 Flash if quality matters most: it scores higher (Spring Prompt overall 60 against 39). Pick Mercury 3 if cost matters more: it costs 5.3 times less per deck on DeckBench.
Which is cheaper, Gemini 3.8 Flash or Mercury 3?
Mercury 3 is cheaper to run: $0.012 against $0.061 per deck on DeckBench (5.3 times less).
Which is better for decks from an analysis, Gemini 3.8 Flash or Mercury 3?
Gemini 3.8 Flash ranks 17 of 24 models on sale for turning a finished analysis into a deck you could present as it is, against 18 for Mercury 3.
Which is better for marketing planning, Gemini 3.8 Flash or Mercury 3?
Gemini 3.8 Flash ranks 7 of 24 models on sale for planning a year of ad spend without overspending, against 18 for Mercury 3.
Which is better for speed under pressure, Gemini 3.8 Flash or Mercury 3?
Gemini 3.8 Flash ranks 7 of 27 models on sale for good decisions against a real clock (fast chess), against 10 for Mercury 3.
Which has the bigger context window, Gemini 3.8 Flash or Mercury 3?
Gemini 3.8 Flash: 1,048,576 tokens, against 1,000,000 for Mercury 3.
Run Gemini 3.8 Flash and Mercury 3 on your own prompt
Benchmarks aren't your data. Try both side by side in the playground, with the cost of every answer.