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Head-to-head comparison

Mistral Medium 3.5 vs GPT-5.5

Mistral Medium 3.5 (Mistral AI) and GPT-5.5 (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 18 August 2026

As of 18 August 2026, GPT-5.5 holds the stronger ModelCap Index position (#8 vs #38); Mistral Medium 3.5 is 4× cheaper per output token ($7.50/1M vs $30.00/1M); and GPT-5.5 offers the longer context window (1M vs 262K tokens).

Which should you choose?

Choose Mistral Medium 3.5 if…

  • API cost matters — $7.50/1M output tokens against $30.00/1M, about 4× cheaper.
  • your workload is prompt-heavy — input tokens cost $1.50/1M against $5.00/1M.
  • you want the more recently listed model — Mistral Medium 3.5 was listed 30 April 2026, GPT-5.5 24 April 2026.

Choose GPT-5.5 if…

  • you want the stronger overall ModelCap Index position — #8 against #38 (75.7 vs 53.9 points).
  • you need the longer context window — 1M tokens against 262K.
  • you want provider choice — 3 listed API providers against 1.
  • Arena coding is your yardstick — 1520 against 1479.
  • LMArena Agent is your yardstick — 8.9% against -7.0%.
  • Artificial Analysis Intelligence Index is your yardstick — 56.3 against 30.4.

Mistral Medium 3.5 vs GPT-5.5: specs, pricing and context

Specification comparison of Mistral Medium 3.5 and GPT-5.5
FieldMistral Medium 3.5Mistral AIGPT-5.5OpenAI
ModelCap Index position#38#8
Index score53.975.7
EvidenceMeasuredMeasured
Input price / 1M tokens$1.50$5.00
Output price / 1M tokens$7.50$30.00
Context window262K tokens1M tokens
Max output tokens—128K
API providers listed13
Weight accessAPI onlyAPI only
Input modalitiesText, Image, FileFile, Image, Text
First listed30 April 202624 April 2026
PublisherMistral AIOpenAI

Evidence: 4 public benchmark observations across 4 boards · 8 public benchmark observations across 8 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Mistral Medium 3.5 vs GPT-5.5

Public benchmark boards where Mistral Medium 3.5 or GPT-5.5 has a published result
BoardMistral Medium 3.5GPT-5.5Leads
Arena codingArena (LMArena)14791468–149015201513–1526HighGPT-5.5
LMArena AgentLMArena-7.0%-9.0%–-5.0%8.9%7.9%–9.9%X-HighGPT-5.5
ARC-AGI-2ARC Prize Foundation—85.0%X-HighOnly one result
ARC-AGI-3ARC Prize Foundation—0.4%HighOnly one result
Artificial Analysis Intelligence IndexArtificial Analysis30.4intelligence-index56.3intelligence-indexGPT-5.5
Terminal-Bench 2.1 Terminus 2Terminal-Bench—78.0X-HighOnly one result
WildClawBench OpenClawWildClawBench—58.2Only one result

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 GPT-5.5: common questions

Is Mistral Medium 3.5 better than GPT-5.5?

GPT-5.5 ranks higher on the ModelCap Index as of 18 August 2026: #8 against #38. 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 GPT-5.5?

Mistral Medium 3.5 is cheaper on output tokens: $7.50/1M against $30.00/1M. Input tokens are $1.50/1M for Mistral Medium 3.5 and $5.00/1M for GPT-5.5. 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 GPT-5.5?

GPT-5.5 has the larger context window: 1M tokens against 262K.

Which is better for coding, Mistral Medium 3.5 or GPT-5.5?

Arena coding: Mistral Medium 3.5 1479, GPT-5.5 1520 — GPT-5.5 leads.

Are Mistral Medium 3.5 and GPT-5.5 open-weight models?

Mistral Medium 3.5: API only. GPT-5.5: 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 GPT-5.5?

ModelCap currently lists 1 API provider for Mistral Medium 3.5 and 3 for GPT-5.5, 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 GPT-5.5 comparison?

Every figure comes from the sealed ModelCap dataset published 18 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.

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