API cost decision in 10 seconds

🔥GPT-5.5 vs 🔥Gemini 3.1 Pro Preview

Pick Gemini 3.1 Pro Preview for lower cost; pick GPT-5.5 only if the larger context window matters more.

Pricing data updated:  Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Gemini 3.1 Pro Preview for lower cost; pick GPT-5.5 only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Gemini 3.1 Pro Preview is estimated at $8 vs $20 for GPT-5.5, saving $12 (60% lower).

Cost-first pickGemini 3.1 Pro Preview
Context-first pickGPT-5.5
Sample savings$1260%
10x traffic gap$120

GPT-5.5 has more context, but Gemini 3.1 Pro Preview saves $12 on the standard workload. At 10x that traffic, the same price gap is about $120. Use the calculator below to replace the sample workload with your own token volume.

Cheaper input Gemini 3.1 Pro Preview $5 vs $2 / 1M

Gemini 3.1 Pro Preview is $3 cheaper per 1M input tokens (60% lower; 2.5x difference).

Cheaper output Gemini 3.1 Pro Preview $30 vs $12 / 1M

Gemini 3.1 Pro Preview is $18 cheaper per 1M output tokens (60% lower; 2.5x difference).

Larger context GPT-5.5 1.05M vs 1.05M

GPT-5.5 has 1.42K more context (1x larger).

Sample workload Gemini 3.1 Pro Preview $20 vs $8

Gemini 3.1 Pro Preview is $12 cheaper on the standard workload (60% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
GPT-5.5 Calculating… Estimated API cost
Gemini 3.1 Pro Preview 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

Gemini 3.1 Pro Preview has the lower input price; Gemini 3.1 Pro Preview has the lower output price; GPT-5.5 offers the larger context window. For the 1M input plus 500K output sample, Gemini 3.1 Pro Preview is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $20 for GPT-5.5 and $8 for Gemini 3.1 Pro Preview.

Best Fit

Choose GPT-5.5 when you care most about larger context window.

Choose Gemini 3.1 Pro Preview 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, Gemini 3.1 Pro Preview is estimated at $8 vs $20 for GPT-5.5, saving $12 (60% lower).
  • Gemini 3.1 Pro Preview is $12 cheaper on the standard workload (60% lower).
  • Gemini 3.1 Pro Preview is $3 cheaper per 1M input tokens (60% lower; 2.5x difference).
  • Gemini 3.1 Pro Preview is $18 cheaper per 1M output tokens (60% lower; 2.5x difference).
  • GPT-5.5 has 1.42K more context (1x larger).
Head-to-Head Specs
Feature🔥GPT-5.5
(OpenAI)
🔥Gemini 3.1 Pro Preview
(Google)
Input Price
prompt tokens per 1M
$5$2
Completion Price
per 1M tokens
$30$12
Sample Workload Cost
1M input + 500K output
$20$8
Context Window1.05M1.05M
Release Date2026-04-242026-02-19
Popularity Rank
current rank
#18#20

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGemini 3.1 Pro PreviewOn the standard 1M input plus 500K output workload, Gemini 3.1 Pro Preview is estimated at $8 vs $20 for GPT-5.5, saving $12 (60% lower).
High-volume input processingGemini 3.1 Pro PreviewLower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsGemini 3.1 Pro PreviewLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGPT-5.5A larger context window leaves more room for retrieved passages, conversation history, or source files.

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GPT-5.5

GPT-5.5 is OpenAI’s frontier model designed for complex professional workloads, building on GPT-5.4 with stronger reasoning, higher reliability, and improved token efficiency on hard tasks. It features a 1M+ token...

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...