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Mistral: Mistral Small 4

Mistral: Mistral Small 4 is mistralai's model. On the un-leaked meo benchmark it ranks #48 of 82 with 57.7% accuracy and an Effective Value (𝕍) of 0.0027 β€” earning a correct answer for about $0.0046 in 55s each.

as of 2026-10-18

meo rank
#48
of 82
Accuracy
57.7%
overall
𝕍 index (top=100)
0.065
raw 𝕍 0.0027 Β· N=10
$ / correct
$0.0046
55s each

Per-domain accuracy

143 correct of 250 questions asked across 11 domains Β· answer rate 100% Β· macro accuracy 56.9%. Headline accuracy is micro-averaged per meo’s methodology; per-domain question counts (correct/asked) are shown so you can judge significance.

Base-rate bias
76%31/41
Regex automaton
75%12/16
CSP (unsatisfiable)
69%11/16
Logic / math / CS
68%23/34
Framework bias
67%2/3
Tape machine
53%8/15
Perceptual illusions
51%52/102
Watson-Glaser
50%2/4
Theory of mind
33%1/3
Long arithmetic
7%1/15
State tracking
0%0/1

Efficiency

Cost per correct
$0.0046
Seconds per correct
55
Tokens per correct
6,423
Correct answers
143 / 250
Total benchmark cost
$0.65
Avg tokens / item
3,674

Model details

Released
2026-03-16
Weights
Open
Context
262K
Max output
210K
Knowledge cutoff
β€”
Price in
$0.15/M
Price out
$0.60/M
Modality
text+image->text

Sources: openrouter Β· meo

FAQ

How accurate is Mistral: Mistral Small 4?

Mistral: Mistral Small 4 scores 57.7% overall on the meo benchmark (rank #48 of 82), an un-leaked private holdout graded objective-first.

What is Mistral: Mistral Small 4's Effective Value?

Its Effective Value (𝕍) is 0.0027 at N=10, Ο‰=1, Ξ΄=1.5 β€” a fused metric of accuracy, speed, cost, and error-cascade. 𝕍 rankings shift with task depth.

How much does Mistral: Mistral Small 4 cost per correct answer?

About $0.0046 per correct answer (6,423 tokens, 55 seconds each) at benchmark-time pricing via OpenRouter.

Is Mistral: Mistral Small 4 open weights?

Yes β€” Mistral: Mistral Small 4 is released with open weights.

Benchmark updates affecting this model

  • 2026-06-09majorlogic_math_cs ground truth was broken β€” culled and rebuilt with solver-verified items

    A 5-lab frontier jury revealed that 29 of 37 LLM-authored logic_math_cs items had broken ground truth: on most, five independent frontier models unanimously concluded the clue sets were contradictory while the stored answer claimed a number, and on eight, all five agreed on the SAME different number (author arithmetic errors). Models were being marked wrong for being right. The 29 were retired (full audit published in the repo) and the domain rebuilt with generator-as-oracle items: an embedded constraint solver PROVES each puzzle has exactly one solution (or provably none), verified by an independent exhaustive enumerator. A 3-round difficulty study found frontier models saturate consistent human-scale logic puzzles, so items use anonymous global constraints and carry a measured difficulty gradient.

  • 2026-06-08majorCorrected base_bias grading (LLM-equivalence judge fix)

    The LLM-equivalence grader uses a reasoning model whose verdict token budget was too small, so its YES/NO answer was emitted as empty and silently counted as a failure. This understated the base_bias domain to ~7% for every model when the true accuracy is ~85-90%. We raised the judge budget, excluded its reasoning tokens from the verdict, switched to verbosity-robust conclusion matching, and re-graded the whole board.

Full benchmark changelog β†’

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Show Mistral: Mistral Small 4’s meo rank on your site β€” the badge links back here.

Related: all Mistral AI models Β· Base-rate bias domain Β· best Effective Value Β· biggest movers Β· methodology Β· full leaderboard.