Compare / Mercury 3 vs Mistral Medium 3.5

Mercury 3 vs Mistral Medium 3.5

Which is cheaper, which is more capable, and which does better at each kind of work, from 56 results on 4 sources that measured both models.

InceptionMercury 3 Released 19 Oct 2026 · $0.20 in · $0.70 out
Mistral AIMistral Medium 3.5 Released 28 Apr 2026 · $1.50 in · $7.50 out
Mercury 3 wins 3012 too close to callMistral Medium 3.5 wins 14

Of the 56 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).

Mercury 3 or Mistral Medium 3.5? The short answer

Pick Mercury 3: it scores higher (Spring Prompt overall 39 against 16) and costs less.

  • Spring Prompt overall: Mercury 3 39, Mistral Medium 3.5 16 (out of 100; how the score works).
  • Mercury 3 is cheaper to run: $0.012 against $0.045 per deck on DeckBench (3.9 times less).
  • Mercury 3 is newer: released 19 Oct 2026, against 28 Apr 2026 for Mistral Medium 3.5.
  • On our own benchmarks, on the results both models have: Mercury 3 does better for marketing planning.

Head to head

39
Spring Prompt overall
16
$0.33
Price per million tokens, blendedlower is better
$3.00
1,000,000
Context window, tokens
262,144

Every fact side by side

Mercury 3Mistral Medium 3.5
Price per million tokens$0.20 in · $0.70 out$1.50 in · $7.50 out
Blended (3 in : 1 out)$0.33$3.00
Cheapest host, blended–$3.00 (Mistral)
Cost per deck (DeckBench)$0.012$0.045
Cached input, per million$0.020 cached input$0.15 cached input
Intelligence Index–14.2
Spring Prompt overall3916
Output speed, tokens a second–157
Context window1,000,000 tokens262,144 tokens
Released19 Oct 2026 (newer)28 Apr 2026
WeightsClosedClosed
Developer based inthe USFrance

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 not measured 18 of 24
Decks from an analysisTurning a finished analysis into a deck you could present as it is 18 of 24 22 of 24
User surveysPlanning a user survey and reading its results without being misled 9 of 13 11 of 13
Marketing planningPlanning a year of ad spend without overspending 18 of 24 24 of 24
Agents and tool useMulti-step tasks with tools: support desks, coding agents, function calls not measured 97 of 168
Reasoning and knowledgeHard questions across science, maths and general knowledge not measured 126 of 202
WritingWhat people prefer in blind comparisons, and judged writing quality not measured 87 of 189
Sticking to the factsSummarising without inventing things, and factual answers not measured 101 of 153
Speed under pressureGood decisions against a real clock (fast chess) 10 of 27 9 of 27

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.

First slide of Mercury 3's deck for Hearthside Coffee
Mercury 3 · deck rating 812 · needs work
First slide of Mistral Medium 3.5's deck for Hearthside Coffee
Mistral Medium 3.5 · deck rating 656 · needs work

Every slide, side by side →

From our research

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.

MeasureMercury 3Mistral Medium 3.5
BulletBench measured by Spring Prompt · 3 results
Cost per game · Bullet 60sUS dollars, lower is better 7 · 28 of 32 measured $0.0020no reasoning $0.0354no reasoning
Ladder Elo · Bullet 60sladder Elo, higher is better 15 · 8 of 32 measured 491no reasoning 572no reasoning
Ladder Elo · Lightning 10+1ladder Elo, higher is better 12 · 13 of 24 measured 555no reasoning 529
DeckBench measured by Spring Prompt · 3 results
Cost per deckUS dollars, lower is better 4 · 8 of 24 measured $0.0116 $0.0448
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. 18 · 22 of 24 measured 812 656
Accurate decks% of tasks, higher is better 20 · 20 of 24 measured 0.0% 0.0%
ROASBench measured by Spring Prompt · 3 results
Overall scorescore out of 100, higher is better 18 · 24 of 24 measured 26.1 15.2
Audience scorescore out of 100, higher is better 21 · 24 of 24 measured 43.2 28.5
Business scorescore out of 100, higher is better 18 · 24 of 24 measured 17.6 3.4
SurveyBench measured by Spring Prompt · 3 results
Analysis ratingrating, higher is betterThe rating weighs each win by how strong the other analysis was; the win rate counts wins against whichever analyses a model happened to meet, so the two can disagree. 9 · 11 of 13 measured 752 597
Cost per taskUS dollars, lower is better 3 · 6 of 12 measured $0.0216 $0.0730
Analysis scorepoints of 100, higher is better 12 · 10 of 13 measured 42.2 56.7
Show all 56 results (44 more)
MeasureMercury 3Mistral Medium 3.5
BulletBench measured by Spring Prompt · 7 results
Cost per game · Lightning 10+1US dollars, lower is better 5 · 23 of 24 measured $0.0010no reasoning $0.0297
Games lost on time · Bullet 60s% of games, lower is better 1 · 1 of 32 measured 0.0%no reasoning 0.0%no reasoning
Games lost on time · Lightning 10+1% of games, lower is better 1 · 1 of 24 measured 0.0%no reasoning 0.0%
Invalid moves · Bullet 60s% of moves, lower is better 1 · 28 of 32 measured 0.0%low reasoning 0.4%no reasoning
Invalid moves · Lightning 10+1% of moves, lower is better 18 · 1 of 24 measured 0.4%no reasoning 0.0%no reasoning
Median move time · Bullet 60smilliseconds, lower is better 3 · 6 of 32 measured 0.4 sno reasoning 0.5 sno reasoning
Median move time · Lightning 10+1milliseconds, lower is better 3 · 4 of 24 measured 0.4 sno reasoning 0.5 s
DeckBench measured by Spring Prompt · 14 results
Caveat dropped% of tasks, lower is better 12 · 1 of 24 measured 16.7% 0.0%
Clean layout% of tasks, higher is better 6 · 6 of 24 measured 66.7% 66.7%
Design quality% of the maximum, higher is better 16 · 22 of 24 measured 58.5% 43.7%
Draft figure quoted% of tasks, lower is better 12 · 19 of 24 measured 33.3% 50.0%
Findings missing% of tasks, lower is better 17 · 1 of 24 measured 16.7% 0.0%
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. 16 · 22 of 24 measured 44.0% 25.8%
Layout defects% of tasks, lower is better 6 · 6 of 24 measured 33.3% 33.3%
Misleading metric used% of tasks, lower is better 22 · 1 of 24 measured 16.7% 0.0%
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 22 · 17 of 24 measured 83.3% 50.0%
Slides needing work% of tasks, lower is better 7 · 11 of 24 measured 33.3% 50.0%
Time per deckseconds, lower is better 9 · 2 of 24 measured 83.3 25.0
Unsupported claims% of tasks, lower is better 11 · 17 of 24 measured 16.7% 33.3%
Unsupported numbers% of tasks, lower is better 20 · 1 of 24 measured 16.7% 0.0%
ROASBench measured by Spring Prompt · 6 results
Consistency scorescore out of 100, higher is better 19 · 23 of 24 measured 15.1 8.7
Contribution profitsimulated US dollars, higher is better 18 · 23 of 24 measured $104,868 −$159,882
Cost of a runUS dollars, lower is better 6 · 10 of 24 measured $0.0533 $0.15
Months over budgetmonths of 12, lower is better 1 · 24 of 24 measured 0 3
Planning scorescore out of 100, higher is better 23 · 2 of 24 measured 53.8 55.2
Return on ad spendprofit per $1 spent, higher is better 18 · 23 of 24 measured $0.10 −$0.17
SurveyBench measured by Spring Prompt · 17 results
Head-to-head win rate% of comparisons, higher is betterThe rating weighs each win by how strong the other analysis was; the win rate counts wins against whichever analyses a model happened to meet, so the two can disagree. 6 · 11 of 13 measured 48.6% 24.3%
Leading or double-barrelled questions% of tasks, lower is better 8 · 8 of 13 measured 55.6% 55.6%
Mistaken next steps% of tasks, lower is better 5 · 12 of 13 measured 22.2% 77.8%
Numbers right% of answers, higher is better 13 · 10 of 13 measured 63.3% 75.5%
Objectives unanswerable% of tasks, lower is better 1 · 7 of 13 measured 0.0% 11.1%
Precision ignored% of tasks, lower is better 1 · 11 of 13 measured 0.0% 100.0%
Research scorepoints of 100, higher is better 11 · 10 of 13 measured 56.8 64.2
Sound research% of tasks, higher is better 6 · 6 of 13 measured 0.0% 0.0%
Stakeholder's view presumed% of tasks, lower is better 7 · 11 of 13 measured 22.2% 33.3%
Survey plan scorepoints of 100, higher is better 6 · 11 of 13 measured 90.8 81.5
Survey structure% of tasks, lower is better 7 · 3 of 13 measured 22.2% 11.1%
Time per taskseconds, lower is better 10 · 2 of 12 measured 194 47.5
Traps handled% of traps, higher is better 11 · 12 of 13 measured 60.7% 59.4%
Traps missed% of tasks, lower is better 7 · 10 of 13 measured 88.9% 100.0%
Unsupported findings% of tasks, lower is better 4 · 10 of 13 measured 44.4% 100.0%
Wrong numbers% of tasks, lower is better 9 · 11 of 13 measured 44.4% 100.0%
Wrong recommendation% of tasks, lower is better 12 · 8 of 13 measured 77.8% 44.4%

Quick answers

Is Mercury 3 better than Mistral Medium 3.5?

Pick Mercury 3: it scores higher (Spring Prompt overall 39 against 16) and costs less.

Which is cheaper, Mercury 3 or Mistral Medium 3.5?

Mercury 3 is cheaper to run: $0.012 against $0.045 per deck on DeckBench (3.9 times less).

Which is better for decks from an analysis, Mercury 3 or Mistral Medium 3.5?

Mercury 3 ranks 18 of 24 models on sale for turning a finished analysis into a deck you could present as it is, against 22 for Mistral Medium 3.5.

Which is better for user surveys, Mercury 3 or Mistral Medium 3.5?

Mercury 3 ranks 9 of 13 models on sale for planning a user survey and reading its results without being misled, against 11 for Mistral Medium 3.5.

Which is better for marketing planning, Mercury 3 or Mistral Medium 3.5?

Mercury 3 ranks 18 of 24 models on sale for planning a year of ad spend without overspending, against 24 for Mistral Medium 3.5.

Which is better for speed under pressure, Mercury 3 or Mistral Medium 3.5?

Mistral Medium 3.5 ranks 9 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, Mercury 3 or Mistral Medium 3.5?

Mercury 3: 1,000,000 tokens, against 262,144 for Mistral Medium 3.5.

Run Mercury 3 and Mistral Medium 3.5 on your own prompt

Benchmarks aren't your data. Try both side by side in the playground, with the cost of every answer.

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