Is Mistral Medium 3.5 better than Mistral Small 4?

On accuracy they are statistically tied: Mistral Medium 3.5 scored 28.8% and Mistral Small 4 32.5% on the same 80 questions from open datasets. Similar accuracy; Mistral Small 4 costs less per question.

Which is cheaper, Mistral Medium 3.5 or Mistral Small 4?

Mistral Small 4 is cheaper: $0.0019 per question as billed, against $0.025. List prices: Mistral Medium 3.5 $1.5 in / $7.5 out, Mistral Small 4 $0.15 in / $0.6 out per million tokens.

Which is faster, Mistral Medium 3.5 or Mistral Small 4?

Mistral Small 4 is faster at 170 output tokens per second, against 145. Time to first token: 0.5 s for Mistral Medium 3.5, 0.5 s for Mistral Small 4.

Which has the larger context window, Mistral Medium 3.5 or Mistral Small 4?

Both accept about the same amount of context: 262k and 262k tokens.

Head to head · tested 27 Oct 2026

Mistral Medium 3.5 vs Mistral Small 4: accuracy, speed and price

Similar accuracy; Mistral Small 4 costs less per question.

MistralMistral Medium 3.528.8% score · #65$0.025 per question145 tok/s

MistralMistral Small 432.5% score · #62$0.0019 per question170 tok/s

Verdict

Built from the measurements below

Accuracy is too close to call: Mistral Medium 3.5 scored 28.8% and Mistral Small 4 32.5% on the same 80 questions, a gap within what chance alone could produce.
Mistral Small 4 is 13× cheaper per question as billed ($0.0019 vs $0.025), reasoning tokens included.
Mistral Small 4 generates text 1.2× faster: 170 tokens per second against 145.

Which should you choose?

Choose Mistral Small 4 for the lower cost per correct answer ($0.0057 against $0.087), faster streaming and open weights you can run yourself. The widest subject gap is in medicine: Mistral Small 4 answered 5 of 11 correctly, Mistral Medium 3.5 3 of 11. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.

Accuracy gap -3.8 points (z = -0.51). A winner is called only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.

Head to head

Same questions, same prompt, same API

Measure	Mistral Medium 3.5	Mistral Small 4	Edge
Verification scoreHigher is better	28.8%	32.5%	Too close to call
Cost per questionLower is better	$0.025	$0.0019	Mistral Small 4
Output speedHigher is better	145	170	Mistral Small 4
Time to first tokenLower is better	0.5 s	0.5 s	Similar
End-to-end response timeLower is better	5.4 s	4.5 s	Mistral Small 4
Tokens per questionLower is better	3,268	3,021	Similar
Context windowHigher is better	262k	262k	Similar

Side by side

Bars are scaled to the larger of the two values. The winner on each measure is marked in bold.

Every measure

Mistral Medium 3.5 first, Mistral Small 4 second

Verification scorehigher is better

Mistral Medium 3.528.8%

Mistral Small 432.5%

Cost per questionlower is better

Mistral Medium 3.5$0.025

Mistral Small 4$0.0019

Output speedhigher is better

Mistral Medium 3.5145

Mistral Small 4170

Time to first tokenlower is better

Mistral Medium 3.50.5 s

Mistral Small 40.5 s

End-to-end response timelower is better

Mistral Medium 3.55.4 s

Mistral Small 44.5 s

Tokens per questionlower is better

Mistral Medium 3.53,268

Mistral Small 43,021

Context windowhigher is better

Mistral Medium 3.5262k

Mistral Small 4262k

Score vs. cost per question

Both models in color, every other model in grey

Results by subject and dataset

Questions answered correctly. Small samples: a gap of one or two questions is noise.

Subject	Questions	Mistral Medium 3.5	Mistral Small 4
Science	30	5/30	7/30
Engineering	15	0/15	0/15
Medicine	11	3/11	5/11
Economics	9	6/9	6/9
Law	6	2/6	2/6
Humanities & social science	9	7/9	6/9
SuperGPQA dataset	50	5/50	7/50
MMLU-Pro dataset	30	18/30	19/30

Specifications and pricing

From OpenRouter's catalogue, plus the leaderboard's test dates

Specification	Mistral Medium 3.5	Mistral Small 4
Creator	Mistral	Mistral
Released	30 Apr 2026	16 Mar 2026
Weights	—	Open weights
Reasoning	Yes	Yes
Input	text, image, file	text, image
Output	text	text
Context window	262k tokens	262k tokens
Knowledge cutoff	—	—
List price in / out per 1M	$1.5 / $7.5	$0.15 / $0.6
Blended price per 1M (3:1)	$3.00	$0.26
Cheapest host	Mistral · $1.5 / $7.5	Mistral · $0.15 / $0.6
Hosts on OpenRouter	1	1
Last tested	27 Oct 2026	26 Oct 2026

Compare any two models →

Mistral Medium 3.5 vs Mistral Small 4: frequently asked questions

Is Mistral Medium 3.5 better than Mistral Small 4?: On accuracy they are statistically tied: Mistral Medium 3.5 scored 28.8% and Mistral Small 4 32.5% on the same 80 questions from open datasets. Similar accuracy; Mistral Small 4 costs less per question.
Which is cheaper, Mistral Medium 3.5 or Mistral Small 4?: Mistral Small 4 is cheaper: $0.0019 per question as billed, against $0.025. List prices: Mistral Medium 3.5 $1.5 in / $7.5 out, Mistral Small 4 $0.15 in / $0.6 out per million tokens.
Which is faster, Mistral Medium 3.5 or Mistral Small 4?: Mistral Small 4 is faster at 170 output tokens per second, against 145. Time to first token: 0.5 s for Mistral Medium 3.5, 0.5 s for Mistral Small 4.
Which has the larger context window, Mistral Medium 3.5 or Mistral Small 4?: Both accept about the same amount of context: 262k and 262k tokens.