API cost decision in 10 seconds

Nano Banana 2 (Gemini 3.1 Flash Image Preview) vs GPT-5.1

Pick Nano Banana 2 (Gemini 3.1 Flash Image Preview) for lower cost; pick GPT-5.1 only if the larger context window matters more.

Page updated: 2026-05-26T10:03:26Z Data confirmed: 2026-05-26T14:08:03Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Nano Banana 2 (Gemini 3.1 Flash Image Preview) for lower cost; pick GPT-5.1 only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Nano Banana 2 (Gemini 3.1 Flash Image Preview) is estimated at $2 vs $6.25 for GPT-5.1, saving $4.25 (68% lower).

Cost-first pickNano Banana 2 (Gemini 3.1 Flash Image Preview)

Context-first pickGPT-5.1

Sample savings$4.2568%

10x traffic gap$42.5

GPT-5.1 has more context, but Nano Banana 2 (Gemini 3.1 Flash Image Preview) saves $4.25 on the standard workload. At 10x that traffic, the same price gap is about $42.5. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Nano Banana 2 (Gemini 3.1 Flash Image Preview) stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Nano Banana 2 (Gemini 3.1 Flash Image Preview)	GPT-5.1
Input-heavy / RAG	5M input + 500K output	Nano Banana 2 (Gemini 3.1 Flash Image Preview)	$4	$11.25
Balanced workload	1M input + 1M output	Nano Banana 2 (Gemini 3.1 Flash Image Preview)	$3.5	$11.25
Output-heavy chatbot	1M input + 5M output	Nano Banana 2 (Gemini 3.1 Flash Image Preview)	$15.5	$51.25

Cheaper input Nano Banana 2 (Gemini 3.1 Flash Image Preview) $0.5 vs $1.25 / 1M

Nano Banana 2 (Gemini 3.1 Flash Image Preview) is $0.75 cheaper per 1M input tokens (60% lower; 2.5x difference).

Cheaper output Nano Banana 2 (Gemini 3.1 Flash Image Preview) $3 vs $10 / 1M

Nano Banana 2 (Gemini 3.1 Flash Image Preview) is $7 cheaper per 1M output tokens (70% lower; 3.33x difference).

Larger context GPT-5.1 131.07K vs 400K

GPT-5.1 has 268.93K more context (3.05x larger).

Sample workload Nano Banana 2 (Gemini 3.1 Flash Image Preview) $2 vs $6.25

Nano Banana 2 (Gemini 3.1 Flash Image Preview) is $4.25 cheaper on the standard workload (68% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Nano Banana 2 (Gemini 3.1 Flash Image Preview) Calculating… Estimated API cost

GPT-5.1 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

Nano Banana 2 (Gemini 3.1 Flash Image Preview) has the lower input price; Nano Banana 2 (Gemini 3.1 Flash Image Preview) has the lower output price; GPT-5.1 offers the larger context window. For the 1M input plus 500K output sample, Nano Banana 2 (Gemini 3.1 Flash Image Preview) is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview) and $6.25 for GPT-5.1.

Best Fit

Choose Nano Banana 2 (Gemini 3.1 Flash Image Preview) when you care most about lower input-token price, and lower output-token price.

Choose GPT-5.1 when you care most about larger context window.

Decision Notes

On the standard 1M input plus 500K output workload, Nano Banana 2 (Gemini 3.1 Flash Image Preview) is estimated at $2 vs $6.25 for GPT-5.1, saving $4.25 (68% lower).
Nano Banana 2 (Gemini 3.1 Flash Image Preview) is $4.25 cheaper on the standard workload (68% lower).
Nano Banana 2 (Gemini 3.1 Flash Image Preview) is $0.75 cheaper per 1M input tokens (60% lower; 2.5x difference).
Nano Banana 2 (Gemini 3.1 Flash Image Preview) is $7 cheaper per 1M output tokens (70% lower; 3.33x difference).
GPT-5.1 has 268.93K more context (3.05x larger).

Head-to-Head Specs

Feature	Nano Banana 2 (Gemini 3.1 Flash Image Preview) (Google)	GPT-5.1 (OpenAI)
Input Price prompt tokens per 1M	$0.5	$1.25
Completion Price per 1M tokens	$3	$10
Sample Workload Cost 1M input + 500K output	$2	$6.25
Context Window	131.07K	400K
Release Date	2026-02-26	2025-11-13

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Nano Banana 2 (Gemini 3.1 Flash Image Preview)	On the standard 1M input plus 500K output workload, Nano Banana 2 (Gemini 3.1 Flash Image Preview) is estimated at $2 vs $6.25 for GPT-5.1, saving $4.25 (68% lower).
High-volume input processing	Nano Banana 2 (Gemini 3.1 Flash Image Preview)	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Nano Banana 2 (Gemini 3.1 Flash Image Preview)	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	GPT-5.1	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

Gemma 4 26B A4B (free) can replace Nano Banana 2 (Gemini 3.1 Flash Image Preview) when lower sample workload cost matters most: $0.
Gemma 4 31B (free) can replace Nano Banana 2 (Gemini 3.1 Flash Image Preview) when lower sample workload cost matters most: $0.
Lyria 3 Pro Preview can replace Nano Banana 2 (Gemini 3.1 Flash Image Preview) when lower sample workload cost matters most: $0.
Lyria 3 Clip Preview can replace Nano Banana 2 (Gemini 3.1 Flash Image 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 Multi-Agent offers 2M context with $5 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
Owl Alpha offers 1.05M context with $0 sample workload cost.

Popular competitors

DeepSeek V4 Flash · DeepSeek · #1
Hy3 preview · Tencent · #2
Claude Opus 4.7 · Anthropic · #3
Claude Sonnet 4.6 · Anthropic · #4

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Google catalog

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OpenAI catalog

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Nano Banana 2 (Gemini 3.1 Flash Image Preview)

Gemini 3.1 Flash Image Preview, a.k.a. "Nano Banana 2," is Google’s latest state of the art image generation and editing model, delivering Pro-level visual quality at Flash speed. It combines...

GPT-5.1

GPT-5.1 is the latest frontier-grade model in the GPT-5 series, offering stronger general-purpose reasoning, improved instruction adherence, and a more natural conversational style compared to GPT-5. It uses adaptive reasoning...