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Head-to-head comparison

Gemini 3.1 Pro Preview vs Gemma 4 31B

Gemini 3.1 Pro Preview (Google) and Gemma 4 31B (Google) 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 22 September 2026

As of 22 September 2026, Gemini 3.1 Pro Preview holds the stronger ModelCap Index position (#17 vs #29); Gemma 4 31B is 35.3× cheaper per output token ($0.34/1M vs $12.00/1M); Gemini 3.1 Pro Preview offers the longer context window (1M vs 262K tokens); and Gemma 4 31B ships open weights.

Which should you choose?

Choose Gemini 3.1 Pro Preview if…

  • you want the stronger overall ModelCap Index position — #17 against #29 (81.5 vs 73.8 points).
  • you need the longer context window — 1M tokens against 262K.
  • Arena coding is your yardstick — 1520 against 1499.
  • AA τ²-Bench Telecom is your yardstick — 95.6% against 65.5%.
  • AA Humanity's Last Exam is your yardstick — 47.0% against 11.8%.

Choose Gemma 4 31B if…

  • API cost matters — $0.34/1M output tokens against $12.00/1M, about 35.3× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.09/1M against $2.00/1M.
  • you want to self-host: Gemma 4 31B ships open weights while Gemini 3.1 Pro Preview is api only.
  • you want provider choice — 11 listed API providers against 2.
  • you want the more recently listed model — Gemma 4 31B was listed 2 April 2026, Gemini 3.1 Pro Preview 19 February 2026.

Gemini 3.1 Pro Preview vs Gemma 4 31B: specs, pricing and context

Specification comparison of Gemini 3.1 Pro Preview and Gemma 4 31B
FieldGemini 3.1 Pro PreviewGoogleGemma 4 31BGoogle
ModelCap Index position#17#29
Index score81.573.8
EvidenceMeasuredMeasured
Input price / 1M tokens$2.00$0.09
Output price / 1M tokens$12.00$0.34
Context window1M tokens262K tokens
Max output tokens66K16K
API providers listed211
Weight accessAPI onlyOpen weights
Input modalitiesAudio, File, Image, Text, VideoImage, Text, Video
First listed19 February 20262 April 2026
PublisherGoogleGoogle

Evidence: 4 public benchmark observations across 4 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Gemini 3.1 Pro Preview vs Gemma 4 31B

Public benchmark boards where Gemini 3.1 Pro Preview or Gemma 4 31B has a published result
BoardGemini 3.1 Pro PreviewGemma 4 31BLeads
Arena codingArena (LMArena)15201515–152514991483–1514Gemini 3.1 Pro Preview
LMArena AgentLMArena-5.8%-6.6%–-5.0%—Only one result
AA Intelligence IndexArtificial Analysis29.7intelligence-index:v4.3:reasoning-unspecified—Only one result
AA τ²-Bench TelecomArtificial Analysis95.6%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="Gemini 3.1 Pro Preview":reasoning=true65.5%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="Gemma 4 31B (Non-reasoning)":reasoning=falseGemini 3.1 Pro Preview
AA Humanity's Last ExamArtificial Analysis47.0%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="Gemini 3.1 Pro Preview":reasoning=true11.8%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="Gemma 4 31B (Non-reasoning)":reasoning=falseGemini 3.1 Pro Preview
WildClawBench OpenClawWildClawBench—37.6Only 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.

Gemini 3.1 Pro Preview vs Gemma 4 31B: common questions

Is Gemini 3.1 Pro Preview better than Gemma 4 31B?

Gemini 3.1 Pro Preview ranks higher on the ModelCap Index as of 22 September 2026: #17 against #29. 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. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is Gemini 3.1 Pro Preview cheaper than Gemma 4 31B?

Gemma 4 31B is cheaper on output tokens: $0.34/1M against $12.00/1M. Input tokens are $2.00/1M for Gemini 3.1 Pro Preview and $0.09/1M for Gemma 4 31B. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $10.00 for Gemini 3.1 Pro Preview versus $0.35 for Gemma 4 31B. Gemma 4 31B costs 96.5% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, Gemini 3.1 Pro Preview or Gemma 4 31B?

Gemini 3.1 Pro Preview has the larger context window: 1M tokens against 262K.

Which is better for coding, Gemini 3.1 Pro Preview or Gemma 4 31B?

Arena coding: Gemini 3.1 Pro Preview 1520, Gemma 4 31B 1499 — Gemini 3.1 Pro Preview leads.

Are Gemini 3.1 Pro Preview and Gemma 4 31B open-weight models?

Gemini 3.1 Pro Preview: API only. Gemma 4 31B: Open weights. 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 Gemma 4 31B?

ModelCap currently lists 2 API providers for Gemini 3.1 Pro Preview and 11 for Gemma 4 31B, 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 Gemma 4 31B comparison?

Every figure comes from the sealed ModelCap dataset published 22 September 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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