Claude Sonnet 4.5 vs Mistral Small 3 (Non-Reasoning)
Wins 4 of 5 areas
Coding · Reasoning · Long documents · Following instructions
Wins 1 of 5 areas
Facts
Claude Sonnet 4.5 is the stronger all-rounder.Mistral Small 3 (Non-Reasoning) is cheaper and better at facts.
Scores updated · 17 tests both models report · How we compare
Where each one wins
Tests won in each of the five areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- ReasoningHard problems that need careful thinking20Claude Sonnet 4.52 of 2 tests
- CodingWriting and fixing software10Claude Sonnet 4.51 of 1 test
- Long documentsFinding answers in very long texts10Claude Sonnet 4.51 of 1 test
- Following instructionsDoing exactly what it is asked10Claude Sonnet 4.51 of 1 test
- FactsGetting facts right instead of making them up01Mistral Small 3 (Non-Reasoning)1 of 1 test
Coding, facts, long documents and following instructions rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
Mistral Small 3 (Non-Reasoning) costs 99% less for the same work.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Sonnet 4.5 pulls ahead
- Graduate-level biology, physics and chemistry questionsGPQA Diamond+37.2points ahead
- Follows unfamiliar, precisely checkable instructionsIFBench+30.9points ahead
- Code for real scientific research problemsSciCode+22.1points ahead
Where Mistral Small 3 (Non-Reasoning) pulls ahead
No clear win on a test scored out of 100.
Every test, side by side
All 17 tests both models report. The winning score is in its model's colour; marks a score checked independently.
ReasoningClaude Sonnet 4.5
- GPQA DiamondClaude Sonnet 4.5 by 37.283.446.2+37.2
- Humanity's Last ExamClaude Sonnet 4.5 by 1417.83.8+14
FactsMistral Small 3 (Non-Reasoning)
- Vectara HHEM hallucination ratelower is betterMistral Small 3 (Non-Reasoning) by 6.9125.1+6.9
Following instructionsClaude Sonnet 4.5
- IFBenchClaude Sonnet 4.5 by 30.957.326.4+30.9
Other results11 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- τ²-Bench Telecom (AA run)Claude Sonnet 4.5 by 58.578.119.6+58.5
- AIR-Bench 2024Claude Sonnet 4.5 by 5789.832.8+57
- HarmBenchClaude Sonnet 4.5 by 46.89245.2+46.8
- AA IntelligenceClaude Sonnet 4.5 by 1420.76.7+14
- vectara_factual_consistencyMistral Small 3 (Non-Reasoning) by 6.98894.9+6.9
- simple_safety_testsClaude Sonnet 4.5 by 6.710093.3+6.7
- bbqClaude Sonnet 4.5 by 5.698.993.3+5.6
- vectara_avg_summary_lengthClaude Sonnet 4.5 by 29 rating points127.898.8+29 rating
- vectara_answer_rateMistral Small 3 (Non-Reasoning) by 2.395.697.9+2.3
- anthropic_red_teamClaude Sonnet 4.5 by 1.898.296.4+1.8
- XSTestClaude Sonnet 4.5 by 1.196.495.3+1.1
Questions people ask
Which is better, Claude Sonnet 4.5 or Mistral Small 3 (Non-Reasoning)?
Claude Sonnet 4.5 wins four of the five areas where both have results: coding, reasoning, long documents and following instructions. Mistral Small 3 (Non-Reasoning) wins facts, and costs 99% less.
Which is better for coding?
Claude Sonnet 4.5. It wins the one coding test both models report.
Which is cheaper?
Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; Mistral Small 3 (Non-Reasoning) costs $0.05 and $0.08. That makes Mistral Small 3 (Non-Reasoning) about 99% cheaper for the same work.
How do you compare the two?
We use the 17 benchmark tests both models have published scores on. The verdict counts the 6 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 11 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.