API cost decision in 10 seconds

Gemma 4 31B (free) vs Nano Banana 2 (Gemini 3.1 Flash Image Preview)

Pick Gemma 4 31B (free) when budget and context both matter.

Page updated: 2026-05-26T10:03:26Z Data confirmed: 2026-05-26T12:43:06Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Gemma 4 31B (free) when budget and context both matter.

On the standard 1M input plus 500K output workload, Gemma 4 31B (free) is estimated at $0 vs $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview), saving $2 (100% lower).

Cost-first pickGemma 4 31B (free)

Context-first pickGemma 4 31B (free)

Sample savings$2100%

10x traffic gap$20

Gemma 4 31B (free) is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $20. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Gemma 4 31B (free) stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Gemma 4 31B (free)	Nano Banana 2 (Gemini 3.1 Flash Image Preview)
Input-heavy / RAG	5M input + 500K output	Gemma 4 31B (free)	$0	$4
Balanced workload	1M input + 1M output	Gemma 4 31B (free)	$0	$3.5
Output-heavy chatbot	1M input + 5M output	Gemma 4 31B (free)	$0	$15.5

Cheaper input Gemma 4 31B (free) $0 vs $0.5 / 1M

Gemma 4 31B (free) is free for input tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $0.5 per 1M tokens.

Cheaper output Gemma 4 31B (free) $0 vs $3 / 1M

Gemma 4 31B (free) is free for output tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $3 per 1M tokens.

Larger context Gemma 4 31B (free) 262.14K vs 131.07K

Gemma 4 31B (free) has 131.07K more context (2x larger).

Sample workload Gemma 4 31B (free) $0 vs $2

Gemma 4 31B (free) is free for the standard workload while the other model is estimated at $2.

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Gemma 4 31B (free) Calculating… Estimated API cost

Nano Banana 2 (Gemini 3.1 Flash Image 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

Gemma 4 31B (free) has the lower input price; Gemma 4 31B (free) has the lower output price; Gemma 4 31B (free) offers the larger context window. For the 1M input plus 500K output sample, Gemma 4 31B (free) is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0 for Gemma 4 31B (free) and $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview).

Best Fit

Choose Gemma 4 31B (free) when you care most about lower input-token price, lower output-token price, and larger context window.

Choose Nano Banana 2 (Gemini 3.1 Flash Image Preview) when its provider, model quality, latency, or availability is more important than the numeric price/context winner.

Decision Notes

On the standard 1M input plus 500K output workload, Gemma 4 31B (free) is estimated at $0 vs $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview), saving $2 (100% lower).
Gemma 4 31B (free) is free for the standard workload while the other model is estimated at $2.
Gemma 4 31B (free) is free for input tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $0.5 per 1M tokens.
Gemma 4 31B (free) is free for output tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $3 per 1M tokens.
Gemma 4 31B (free) has 131.07K more context (2x larger).

Head-to-Head Specs

Feature	Gemma 4 31B (free) (Google)	Nano Banana 2 (Gemini 3.1 Flash Image Preview) (Google)
Input Price prompt tokens per 1M	$0	$0.5
Completion Price per 1M tokens	$0	$3
Sample Workload Cost 1M input + 500K output	$0	$2
Context Window	262.14K	131.07K
Release Date	2026-04-02	2026-02-26

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Gemma 4 31B (free)	On the standard 1M input plus 500K output workload, Gemma 4 31B (free) is estimated at $0 vs $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview), saving $2 (100% lower).
High-volume input processing	Gemma 4 31B (free)	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Gemma 4 31B (free)	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Gemma 4 31B (free)	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.
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.
Gemma 3 4B can replace Nano Banana 2 (Gemini 3.1 Flash Image Preview) when lower sample workload cost matters most: $0.08.

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.
Owl Alpha offers 1.05M context with $0 sample workload cost.
DeepSeek V4 Flash offers 1.05M context with $0.2 sample workload cost.

Popular competitors

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Claude Sonnet 4.6 · Anthropic · #4

Cheaper alternatives

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Provider catalogs

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Google catalog

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Open Google models

Gemma 4 31B (free)

Gemma 4 31B Instruct is Google DeepMind's 30.7B dense multimodal model supporting text and image input with text output. Features a 256K token context window, configurable thinking/reasoning mode, native function...

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...