Claude Opus 4.8 vs Mistral Small 3.1
Wins 6 of 6 areas
Coding · Agents · Reasoning · Facts · Long documents · Following instructions
Wins 0 of 6 areas
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Claude Opus 4.8 is the stronger all-rounder.Mistral Small 3.1 is cheaper.
Scores updated · 18 tests both models report · How we compare
Where each one wins
Tests won in each of the six 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.
- CodingWriting and fixing software30Claude Opus 4.83 of 3 tests
- AgentsCarrying out multi-step tasks on its own30Claude Opus 4.83 of 3 tests
- ReasoningHard problems that need careful thinking30Claude Opus 4.83 of 3 tests
- FactsGetting facts right instead of making them up20Claude Opus 4.82 of 2 tests
- Long documentsFinding answers in very long texts10Claude Opus 4.81 of 1 test
- Following instructionsDoing exactly what it is asked10Claude Opus 4.81 of 1 test
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 3.1 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 Opus 4.8 pulls ahead
- Command-line tasks in a real terminalTerminal-Bench 2.1+58.4points ahead
- Reasons across sets of long documentsAA-LCR+55.4points ahead
- Hard command-line tasks in a real terminalTerminal-Bench Hard+50.7points ahead
Where Mistral Small 3.1 pulls ahead
No clear win on a test scored out of 100.
Every test, side by side
All 18 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 4.8
- Terminal-Bench 2.1Claude Opus 4.8 by 58.484.626.2+58.4
- Terminal-Bench HardClaude Opus 4.8 by 50.758.37.6+50.7
- SciCodeClaude Opus 4.8 by 26.654.427.8+26.6
AgentsClaude Opus 4.8
- GDPValClaude Opus 4.8 by 47.847.80+47.8
- τ-Bench V3 · BankingClaude Opus 4.8 by 26.834.27.4+26.8
- Terminal-Bench 4.0Claude Opus 4.8 by 21.721.70+21.7
ReasoningClaude Opus 4.8
- GPQA DiamondClaude Opus 4.8 by 46.69245.4+46.6
- Humanity's Last ExamClaude Opus 4.8 by 44.448.74.3+44.4
- CritPtClaude Opus 4.8 by 20.920.90+20.9
FactsClaude Opus 4.8
- AA-Omniscience · Non-hallucinationClaude Opus 4.8 by 38.360.722.4+38.3
- AA-Omniscience · AccuracyClaude Opus 4.8 by 33.748.815.1+33.7
Following instructionsClaude Opus 4.8
- IFBenchClaude Opus 4.8 by 32.362.229.9+32.3
Other results5 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.
- AA-OmniscienceClaude Opus 4.8 by 79.528.8-50.8+79.5
- τ²-Bench Telecom (AA run)Claude Opus 4.8 by 69.394.425.1+69.3
- Artificial Analysis Coding IndexClaude Opus 4.8 by 4874.326.3+48
- AA Agentic IndexClaude Opus 4.8 by 40.542.62.1+40.5
- AA IntelligenceClaude Opus 4.8 by 34.741.87.1+34.7
Questions people ask
Which is better, Claude Opus 4.8 or Mistral Small 3.1?
Claude Opus 4.8 wins all six areas where both have results: coding, agents, reasoning, facts, long documents and following instructions. Mistral Small 3.1 wins none, but costs 99% less.
Which is better for coding?
Claude Opus 4.8. It wins 3 of the 3 coding tests both models report; Mistral Small 3.1 wins none.
Which is cheaper?
Claude Opus 4.8 costs $5.00 per million input tokens and $25.00 per million output tokens; Mistral Small 3.1 costs $0.11 and $0.17. That makes Mistral Small 3.1 about 99% cheaper for the same work.
How do you compare the two?
We use the 18 benchmark tests both models have published scores on. The verdict counts the 13 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 5 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.