AI Models · Open-Source vs Paid

Mistral Medium 3.5 Open vs Gemini 3.1 Pro Preview Paid

Mistral Medium 3.5 vs Gemini 3.1 Pro Preview compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.

Prices & specs refreshed from live data · olud.ai

Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.

Mistral Medium 3.5OpenMistral AI
$1.5 /M input
$7.5 /M outputNo per-token fees if you self-host
TypeOpen-weight
Context window262K tokens
MultimodalYes
Self-hostYes
Gemini 3.1 Pro PreviewPaidGoogle
$2 /M input
$12 /M outputManaged API (no infra to run)
TypeProprietary
Context window1M tokens
MultimodalYes
Self-hostNo
Choose Mistral Medium 3.5 if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Gemini 3.1 Pro Preview if you want frontier capability through a managed API with zero infrastructure to run.

Mistral Medium 3.5 vs Gemini 3.1 Pro Preview specs

SpecMistral Medium 3.5Gemini 3.1 Pro PreviewWinner
MakerMistral AIGoogle
TypeOpen-weightProprietaryMistral Medium 3.5
Context window262K tokens1M tokensGemini 3.1 Pro Preview
Input price$1.5/M · free self-host$2/MMistral Medium 3.5
Output price$7.5/M · free self-host$12/MMistral Medium 3.5
Vision / multimodalYesYes= Tie
Tool / function callingYesYes= Tie
Self-hostableYesNo (API only)Mistral Medium 3.5
LicenseApache 2.0ProprietaryMistral Medium 3.5

Price gap & when to choose each

1.6×cheaper per output token

Mistral Medium 3.5 is ~1.6× cheaper than Gemini 3.1 Pro Preview on output tokens ($7.5 vs $12 per M tokens).

Choose Mistral Medium 3.5 if…
  • You want to self-host or run on your cloud
  • You prioritize data privacy & control
  • You want the lowest operating costs
  • You are building open or reproducible AI
Choose Gemini 3.1 Pro Preview if…
  • You want frontier performance through a managed API
  • You need the longer 1M context window
  • You value reliability & ecosystem
  • You don't want to manage infrastructure

Feature comparison

CapabilityMistral Medium 3.5Gemini 3.1 Pro Preview
Open weights (downloadable)
Self-hostable
Runs fully offline
Vision / multimodal
Tool / function calling
1M+ context window

Benchmarks: Mistral Medium 3.5 vs Gemini 3.1 Pro Preview

Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).

Mistral Medium 3.5
Gemini 3.1 Pro Preview
Intelligence index
14.9
30.4
Coding index
46.9
68.8
GPQA
74.8%
94.1%
Humanity's Last Exam
13.8%
47%
Long Context Reasoning
69.3%
82%
SciCode
40.2%
58.7%
IFBench
68.8%
77.1%
τ²-Bench
94.2%
95.6%
τ-Bench Banking
15.1%
21.4%
Terminal-Bench
50.6%
73.8%
Terminal-Bench Hard
33.3%
53.8%
Speed
142.2 tok/s
125.2 tok/s
Latency
0.74s
24.48s
Intelligence per $
5
6.8

Benchmark data by Artificial Analysis.

How Mistral Medium 3.5 and Gemini 3.1 Pro Preview score

🏆 Best value & openness: Mistral Medium 3.5 (4.6 vs 3.2 / 5)
CriterionMistral Medium 3.5Gemini 3.1 Pro Preview
Cost-efficiency4.03.5
Context window4.05.0
Openness5.01.5
Self-hosting5.01.0
Multimodality5.05.0

Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.

What each model is

Mistral Medium 3.5 Open

Mistral AI · Open-weight

Mistral Medium 3.5 is a dense 128B instruction-following model from Mistral AI. It supports text and image inputs with text output, and is designed for agentic workflows, coding, and complex...

Gemini 3.1 Pro Preview Paid

Google · Proprietary

Gemini 3.1 Pro Preview is Google’s frontier reasoning model, delivering enhanced software engineering performance, improved agentic reliability, and more efficient token usage across complex workflows. Building on the multimodal foundation.

Other models in these families

These variants are tracked but not compared here — one page per family keeps the comparison readable.

Other variants tracked
Mistral Medium 3.5 (batch)Mistral Small 4Mistral Small 4 (batch)Mistral Medium 3.1Mistral Medium 3.1 (batch)Mistral Large 3 2512Mistral Large 3 2512 (batch)Devstral 2 2512Mistral Medium 3Mistral Small 3.1 24BMistral Small 3.2 24BMistral LargeMistral Large 2407Mistral Small 3SabaMinistral 3 14B 2512Mixtral 8x22B InstructMinistral 3 8B 2512Ministral 3 8B 2512 (batch)Ministral 3 3B 2512UncensoredCodestral 2508Codestral 2508 (batch)Voxtral Small 24B 2507Mistral Nemo
Other variants tracked
Gemini 3.1 Pro Preview (batch)Gemini 2.5 ProGemini 2.5 Pro (batch)Gemini 2.5 Pro Preview 05-06Gemini 3.1 Pro Preview Custom ToolsNano Banana Pro (Gemini 3 Pro Image Preview)

Frequently asked questions

Is Mistral Medium 3.5 as good as Gemini 3.1 Pro Preview?

Mistral Medium 3.5 is open-weight and competitive on many tasks, but Gemini 3.1 Pro Preview may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.

Can I run Mistral Medium 3.5 locally?

Yes. Mistral Medium 3.5 has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. Gemini 3.1 Pro Preview is API-only and cannot be self-hosted.

How much cheaper is Mistral Medium 3.5?

Mistral Medium 3.5 costs $7.5/M output vs $12/M for Gemini 3.1 Pro Preview — roughly 2x cheaper via API, and free if you self-host.

Mistral Medium 3.5 vs Gemini 3.1 Pro Preview — which should I pick in 2026?

Choose Mistral Medium 3.5 if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Gemini 3.1 Pro Preview if you want frontier capability through a managed API with zero infrastructure to run.

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