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Head-to-head comparison

Claude Opus 5 vs Mistral Medium 3.5

Claude Opus 5 (Anthropic) and Mistral Medium 3.5 (Mistral AI) 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, Claude Opus 5 holds the stronger ModelCap Index position (#2 vs #38); Mistral Medium 3.5 is 3.3× cheaper per output token ($7.50/1M vs $25.00/1M); and Claude Opus 5 offers the longer context window (1M vs 262K tokens).

Which should you choose?

Choose Claude Opus 5 if…

  • you want the stronger overall ModelCap Index position — #2 against #38 (83.0 vs 53.9 points).
  • you need the longer context window — 1M tokens against 262K.
  • you want provider choice — 5 listed API providers against 1.
  • Arena coding is your yardstick — 1531 against 1479.
  • LMArena Agent is your yardstick — 12.2% against -7.0%.
  • Artificial Analysis Intelligence Index is your yardstick — 63.1 against 30.4.
  • you want the more recently listed model — Claude Opus 5 was listed 24 July 2026, Mistral Medium 3.5 30 April 2026.

Choose Mistral Medium 3.5 if…

  • API cost matters — $7.50/1M output tokens against $25.00/1M, about 3.3× cheaper.
  • your workload is prompt-heavy — input tokens cost $1.50/1M against $5.00/1M.

Claude Opus 5 vs Mistral Medium 3.5: specs, pricing and context

Specification comparison of Claude Opus 5 and Mistral Medium 3.5
FieldClaude Opus 5AnthropicMistral Medium 3.5Mistral AI
ModelCap Index position#2#38
Index score83.053.9
EvidenceMeasuredMeasured
Input price / 1M tokens$5.00$1.50
Output price / 1M tokens$25.00$7.50
Context window1M tokens262K tokens
Max output tokens128K—
API providers listed51
Weight accessAPI onlyAPI only
Input modalitiesText, Image, FileText, Image, File
First listed24 July 202630 April 2026
PublisherAnthropicMistral AI

Evidence: 6 public benchmark observations across 6 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: Claude Opus 5 vs Mistral Medium 3.5

Public benchmark boards where Claude Opus 5 or Mistral Medium 3.5 has a published result
BoardClaude Opus 5Mistral Medium 3.5Leads
Arena codingArena (LMArena)15311522–1540High14791468–1490Claude Opus 5
LMArena AgentLMArena12.2%10.7%–13.6%High-7.0%-9.0%–-5.0%Claude Opus 5
ARC-AGI-2ARC Prize Foundation90.4%Max—Only one result
ARC-AGI-3ARC Prize Foundation30.2%High—Only one result
Artificial Analysis Intelligence IndexArtificial Analysis63.1intelligence-index30.4intelligence-indexClaude Opus 5

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.

Claude Opus 5 vs Mistral Medium 3.5: common questions

Is Claude Opus 5 better than Mistral Medium 3.5?

Claude Opus 5 ranks higher on the ModelCap Index as of 18 August 2026: #2 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 Claude Opus 5 cheaper than Mistral Medium 3.5?

Mistral Medium 3.5 is cheaper on output tokens: $7.50/1M against $25.00/1M. Input tokens are $5.00/1M for Claude Opus 5 and $1.50/1M for Mistral Medium 3.5. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Claude Opus 5 or Mistral Medium 3.5?

Claude Opus 5 has the larger context window: 1M tokens against 262K.

Which is better for coding, Claude Opus 5 or Mistral Medium 3.5?

Arena coding: Claude Opus 5 1531, Mistral Medium 3.5 1479 — Claude Opus 5 leads.

Are Claude Opus 5 and Mistral Medium 3.5 open-weight models?

Claude Opus 5: API only. Mistral Medium 3.5: 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 Claude Opus 5 and Mistral Medium 3.5?

ModelCap currently lists 5 API providers for Claude Opus 5 and 1 for Mistral Medium 3.5, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Claude Opus 5 vs Mistral Medium 3.5 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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