Gemini 3.1 Pro vs Mistral Medium 3.5 128B
Wins 7 of 7 areas
Coding · Agents · Reasoning · Facts · Images and charts · Long documents · Following instructions
Wins 0 of 7 areas
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Gemini 3.1 Pro is the stronger all-rounder.Mistral Medium 3.5 128B is cheaper.
Scores updated · 25 tests both models report · How we compare
Where each one wins
Tests won in each of the seven 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 software50Gemini 3.1 Pro5 of 5 tests
- AgentsCarrying out multi-step tasks on its own40Gemini 3.1 Pro4 of 4 tests
- ReasoningHard problems that need careful thinking30Gemini 3.1 Pro3 of 3 tests
- FactsGetting facts right instead of making them up20Gemini 3.1 Pro2 of 2 tests
- Images and chartsUnderstanding pictures, charts and video20Gemini 3.1 Pro2 of 2 tests
- Long documentsFinding answers in very long texts10Gemini 3.1 Pro1 of 1 test
- Following instructionsDoing exactly what it is asked10Gemini 3.1 Pro1 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 Medium 3.5 128B costs 36% 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 Gemini 3.1 Pro pulls ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+37.3points ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+33.2points ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+30.7points ahead
Where Mistral Medium 3.5 128B pulls ahead
No clear win on a test scored out of 100.
Every test, side by side
All 25 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGemini 3.1 Pro
- Terminal-Bench 2.1Gemini 3.1 Pro by 23.273.850.6+23.2
- Terminal-Bench HardGemini 3.1 Pro by 20.553.833.3+20.5
- SciCodeGemini 3.1 Pro by 18.558.740.2+18.5
- LMArena · WebDevGemini 3.1 Pro by 181 rating points14461265+181 rating
- SWE-bench VerifiedGemini 3.1 Pro by 380.677.6+3
AgentsGemini 3.1 Pro
- BrowseCompGemini 3.1 Pro by 37.385.948.6+37.3
- τ-Bench V3 · BankingGemini 3.1 Pro by 6.321.415.1+6.3
- Terminal-Bench 4.0Gemini 3.1 Pro by 440+4
- GDPValGemini 3.1 Pro by 1.514.713.2+1.5
ReasoningGemini 3.1 Pro
- Humanity's Last ExamGemini 3.1 Pro by 33.24713.8+33.2
- GPQA DiamondGemini 3.1 Pro by 19.394.174.8+19.3
- CritPtGemini 3.1 Pro by 17.717.70+17.7
FactsGemini 3.1 Pro
- AA-Omniscience · Non-hallucinationGemini 3.1 Pro by 30.749.118.4+30.7
- AA-Omniscience · AccuracyGemini 3.1 Pro by 30.254.924.7+30.2
Images and chartsGemini 3.1 Pro
- MMMU-ProGemini 3.1 Pro by 17.582.464.9+17.5
- LMArena · VisionGemini 3.1 Pro by 74 rating points12961222+74 rating
Following instructionsGemini 3.1 Pro
- IFBenchGemini 3.1 Pro by 8.377.168.8+8.3
Other results7 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-OmniscienceGemini 3.1 Pro by 68.731.9-36.8+68.7
- Artificial Analysis Coding IndexGemini 3.1 Pro by 21.968.846.9+21.9
- AA IntelligenceGemini 3.1 Pro by 15.529.714.2+15.5
- Finance Agent v2Gemini 3.1 Pro by 10.94332.1+10.9
- τ³-Bench BankingGemini 3.1 Pro by 3.116.513.4+3.1
- τ²-Bench Telecom (AA run)Gemini 3.1 Pro by 1.495.694.2+1.4
- AA Agentic Indextie10.39.4tie
Questions people ask
Which is better, Gemini 3.1 Pro or Mistral Medium 3.5 128B?
Gemini 3.1 Pro wins all seven areas where both have results: coding, agents, reasoning, facts, images and charts, long documents and following instructions. Mistral Medium 3.5 128B wins none, but costs 36% less.
Which is better for coding?
Gemini 3.1 Pro. It wins 5 of the 5 coding tests both models report; Mistral Medium 3.5 128B wins none.
Which is cheaper?
Gemini 3.1 Pro costs $2.00 per million input tokens and $12.00 per million output tokens; Mistral Medium 3.5 128B costs $1.50 and $7.50. That makes Mistral Medium 3.5 128B about 36% cheaper for the same work.
How do you compare the two?
We use the 25 benchmark tests both models have published scores on. The verdict counts the 18 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 7 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.