API cost decision in 10 seconds

Gemini 3.1 Pro Preview vs GPT-5

Pick GPT-5 for lower cost; pick Gemini 3.1 Pro Preview only if the larger context window matters more.

Page updated:  Data confirmed:  Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick GPT-5 for lower cost; pick Gemini 3.1 Pro Preview only if the larger context window matters more.

On the standard 1M input plus 500K output workload, GPT-5 is estimated at $6.25 vs $8 for Gemini 3.1 Pro Preview, saving $1.75 (21.9% lower).

Cost-first pickGPT-5
Context-first pickGemini 3.1 Pro Preview
Sample savings$1.7521.9%
10x traffic gap$17.5

Gemini 3.1 Pro Preview has more context, but GPT-5 saves $1.75 on the standard workload. At 10x that traffic, the same price gap is about $17.5. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

GPT-5 stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickGemini 3.1 Pro PreviewGPT-5
Input-heavy / RAG5M input + 500K outputGPT-5$16$11.25
Balanced workload1M input + 1M outputGPT-5$14$11.25
Output-heavy chatbot1M input + 5M outputGPT-5$62$51.25
Cheaper input GPT-5 $2 vs $1.25 / 1M

GPT-5 is $0.75 cheaper per 1M input tokens (37.5% lower; 1.6x difference).

Cheaper output GPT-5 $12 vs $10 / 1M

GPT-5 is $2 cheaper per 1M output tokens (16.7% lower; 1.2x difference).

Larger context Gemini 3.1 Pro Preview 1.05M vs 400K

Gemini 3.1 Pro Preview has 648.58K more context (2.62x larger).

Sample workload GPT-5 $8 vs $6.25

GPT-5 is $1.75 cheaper on the standard workload (21.9% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
Gemini 3.1 Pro Preview Calculating… Estimated API cost
GPT-5 Calculating… Estimated API cost
Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

GPT-5 has the lower input price; GPT-5 has the lower output price; Gemini 3.1 Pro Preview offers the larger context window. For the 1M input plus 500K output sample, GPT-5 is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $8 for Gemini 3.1 Pro Preview and $6.25 for GPT-5.

Best Fit

Choose Gemini 3.1 Pro Preview when you care most about larger context window.

Choose GPT-5 when you care most about lower input-token price, and lower output-token price.

Decision Notes
  • On the standard 1M input plus 500K output workload, GPT-5 is estimated at $6.25 vs $8 for Gemini 3.1 Pro Preview, saving $1.75 (21.9% lower).
  • GPT-5 is $1.75 cheaper on the standard workload (21.9% lower).
  • GPT-5 is $0.75 cheaper per 1M input tokens (37.5% lower; 1.6x difference).
  • GPT-5 is $2 cheaper per 1M output tokens (16.7% lower; 1.2x difference).
  • Gemini 3.1 Pro Preview has 648.58K more context (2.62x larger).
Head-to-Head Specs
FeatureGemini 3.1 Pro Preview
(Google)		GPT-5
(OpenAI)
Input Price
prompt tokens per 1M		$2$1.25
Completion Price
per 1M tokens		$12$10
Sample Workload Cost
1M input + 500K output		$8$6.25
Context Window1.05M400K
Release Date
Popularity#28#57

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGPT-5On the standard 1M input plus 500K output workload, GPT-5 is estimated at $6.25 vs $8 for Gemini 3.1 Pro Preview, saving $1.75 (21.9% lower).
High-volume input processingGPT-5Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsGPT-5Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGemini 3.1 Pro PreviewA larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • Gemma 4 31B (free) can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.
  • Gemma 4 26B A4B (free) can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.
  • Lyria 3 Clip Preview can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.
  • Lyria 3 Pro Preview can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.
Larger context near this budget
  • Llama 4 Scout offers 10M context with $0.23 sample workload cost.
  • Grok 4.20 offers 2M context with $2.5 sample workload cost.
  • Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
  • GPT-5.4 offers 1.05M context with $10 sample workload cost.

Cheaper alternatives

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Larger context alternatives

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Provider catalogs

Compare models within provider hubs before choosing a final API vendor.

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Google catalog

Review all tracked Google models before deciding whether this matchup is the right shortlist.

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OpenAI catalog

Check other OpenAI models with comparable pricing, context, or release timing.

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Gemini 3.1 Pro Preview

Gemini 3.1 Pro Preview is Google’s frontier reasoning model, delivering enhanced software engineering performance, improved agentic reliability, and more efficient token usage across complex workflows. Building on the multimodal foundation...

GPT-5

GPT-5 is OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. It is optimized for complex tasks that require step-by-step reasoning, instruction following, and accuracy...