Skip to content
ModelCap

Head-to-head comparison

Mistral Medium 3.5 vs o3

Mistral Medium 3.5 (Mistral AI) and o3 (OpenAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 17 August 2026

As of 17 August 2026, o3 holds the stronger ModelCap Index position (#38 vs #40); Mistral Medium 3.5 is cheaper per output token ($7.50/1M vs $8.00/1M); and Mistral Medium 3.5 offers the longer context window (262K vs 200K tokens).

Which should you choose?

Choose Mistral Medium 3.5 if…

  • API cost matters — $7.50/1M output tokens against $8.00/1M.
  • your workload is prompt-heavy — input tokens cost $1.50/1M against $2.00/1M.
  • you need the longer context window — 262K tokens against 200K.
  • Arena coding is your yardstick — 1479 against 1460.
  • you want the more recently listed model — Mistral Medium 3.5 was listed 30 April 2026, o3 16 April 2025.

Choose o3 if…

  • you want the stronger overall ModelCap Index position — #38 against #40 (55.1 vs 54.0 points).
  • Artificial Analysis Intelligence Index is your yardstick — 31.1 against 30.4.

Mistral Medium 3.5 vs o3: specs, pricing and context

Specification comparison of Mistral Medium 3.5 and o3
FieldMistral Medium 3.5Mistral AIo3OpenAI
ModelCap Index position#40#38
Index score54.055.1
EvidenceMeasuredMeasured
Input price / 1M tokens$1.50$2.00
Output price / 1M tokens$7.50$8.00
Context window262K tokens200K tokens
Max output tokens—100K
API providers listed11
Weight accessAPI onlyAPI only
Input modalitiesText, Image, FileImage, Text, File
First listed30 April 202616 April 2025
PublisherMistral AIOpenAI

Evidence: 4 public benchmark observations across 4 boards · 4 public benchmark observations across 4 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Mistral Medium 3.5 vs o3

Public benchmark boards where Mistral Medium 3.5 or o3 has a published result
BoardMistral Medium 3.5o3Leads
Arena codingArena (LMArena)14791468–149014601453–1466Mistral Medium 3.5
LMArena AgentLMArena-7.0%-9.0%–-5.0%—Only one result
ARC-AGI-2ARC Prize Foundation—6.5%HighOnly one result
Artificial Analysis Intelligence IndexArtificial Analysis30.4intelligence-index31.1intelligence-indexo3

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Mistral Medium 3.5 vs o3: common questions

Is Mistral Medium 3.5 better than o3?

o3 ranks higher on the ModelCap Index as of 17 August 2026: #38 against #40. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it.

Is Mistral Medium 3.5 cheaper than o3?

Mistral Medium 3.5 is cheaper on output tokens: $7.50/1M against $8.00/1M. Input tokens are $1.50/1M for Mistral Medium 3.5 and $2.00/1M for o3. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Mistral Medium 3.5 or o3?

Mistral Medium 3.5 has the larger context window: 262K tokens against 200K.

Which is better for coding, Mistral Medium 3.5 or o3?

Arena coding: Mistral Medium 3.5 1479, o3 1460 — Mistral Medium 3.5 leads.

Are Mistral Medium 3.5 and o3 open-weight models?

Mistral Medium 3.5: API only. o3: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Mistral Medium 3.5 and o3?

ModelCap currently lists 1 API provider for Mistral Medium 3.5 and 1 for o3, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Mistral Medium 3.5 vs o3 comparison?

Every figure comes from the sealed ModelCap dataset published 17 August 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

Explore further