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Head-to-head comparison

Gemini 3.1 Pro Preview vs o3

Gemini 3.1 Pro Preview (Google) 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 18 August 2026

As of 18 August 2026, Gemini 3.1 Pro Preview holds the stronger ModelCap Index position (#7 vs #37); o3 is 1.5× cheaper per output token ($8.00/1M vs $12.00/1M); and Gemini 3.1 Pro Preview offers the longer context window (1M vs 200K tokens).

Which should you choose?

Choose Gemini 3.1 Pro Preview if…

  • you want the stronger overall ModelCap Index position — #7 against #37 (78.1 vs 55.1 points).
  • you need the longer context window — 1M tokens against 200K.
  • you want provider choice — 2 listed API providers against 1.
  • Arena coding is your yardstick — 1521 against 1460.
  • Artificial Analysis Intelligence Index is your yardstick — 47.7 against 31.1.
  • you want the more recently listed model — Gemini 3.1 Pro Preview was listed 19 February 2026, o3 16 April 2025.

Choose o3 if…

  • API cost matters — $8.00/1M output tokens against $12.00/1M, about 1.5× cheaper.

Gemini 3.1 Pro Preview vs o3: specs, pricing and context

Specification comparison of Gemini 3.1 Pro Preview and o3
FieldGemini 3.1 Pro PreviewGoogleo3OpenAI
ModelCap Index position#7#37
Index score78.155.1
EvidenceMeasuredMeasured
Input price / 1M tokens$2.00$2.00
Output price / 1M tokens$12.00$8.00
Context window1M tokens200K tokens
Max output tokens66K100K
API providers listed21
Weight accessAPI onlyAPI only
Input modalitiesAudio, File, Image, Text, VideoImage, Text, File
First listed19 February 202616 April 2025
PublisherGoogleOpenAI

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: Gemini 3.1 Pro Preview vs o3

Public benchmark boards where Gemini 3.1 Pro Preview or o3 has a published result
BoardGemini 3.1 Pro Previewo3Leads
Arena codingArena (LMArena)15211516–152614601453–1466Gemini 3.1 Pro Preview
LMArena AgentLMArena-0.4%-1.2%–0.3%—Only one result
ARC-AGI-2ARC Prize Foundation—6.5%HighOnly one result
SWE-benchSWE-bench (Princeton / SWE-agent team)—58.4%Only one result
BFCL V4UC Berkeley (Gorilla)—63.1PromptOnly one result
Artificial Analysis Intelligence IndexArtificial Analysis47.7intelligence-index31.1intelligence-indexGemini 3.1 Pro Preview

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.

Gemini 3.1 Pro Preview vs o3: common questions

Is Gemini 3.1 Pro Preview better than o3?

Gemini 3.1 Pro Preview ranks higher on the ModelCap Index as of 18 August 2026: #7 against #37. 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 Gemini 3.1 Pro Preview cheaper than o3?

o3 is cheaper on output tokens: $8.00/1M against $12.00/1M. Input tokens are $2.00/1M for Gemini 3.1 Pro Preview 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, Gemini 3.1 Pro Preview or o3?

Gemini 3.1 Pro Preview has the larger context window: 1M tokens against 200K.

Which is better for coding, Gemini 3.1 Pro Preview or o3?

Arena coding: Gemini 3.1 Pro Preview 1521, o3 1460 — Gemini 3.1 Pro Preview leads.

Are Gemini 3.1 Pro Preview and o3 open-weight models?

Gemini 3.1 Pro Preview: 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 Gemini 3.1 Pro Preview and o3?

ModelCap currently lists 2 API providers for Gemini 3.1 Pro Preview 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 Gemini 3.1 Pro Preview vs o3 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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