API cost decision in 10 seconds

gpt-oss-20b (free) vs Nano Banana 2 (Gemini 3.1 Flash Image Preview)

Pick gpt-oss-20b (free) when budget is the priority.

Page updated: 2026-05-26T15:08:08Z Data confirmed: 2026-05-26T18:08:02Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick gpt-oss-20b (free) when budget is the priority.

On the standard 1M input plus 500K output workload, gpt-oss-20b (free) is estimated at $0 vs $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview), saving $2 (100% lower).

Cost-first pickgpt-oss-20b (free)

Context-first pickBoth models

Sample savings$2100%

10x traffic gap$20

The reported context window is tied, so cost and provider fit carry more weight. 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.

gpt-oss-20b (free) stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	gpt-oss-20b (free)	Nano Banana 2 (Gemini 3.1 Flash Image Preview)
Input-heavy / RAG	5M input + 500K output	gpt-oss-20b (free)	$0	$4
Balanced workload	1M input + 1M output	gpt-oss-20b (free)	$0	$3.5
Output-heavy chatbot	1M input + 5M output	gpt-oss-20b (free)	$0	$15.5

Cheaper input gpt-oss-20b (free) $0 vs $0.5 / 1M

gpt-oss-20b (free) is free for input tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $0.5 per 1M tokens.

Cheaper output gpt-oss-20b (free) $0 vs $3 / 1M

gpt-oss-20b (free) is free for output tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $3 per 1M tokens.

Larger context Tie 131.07K vs 131.07K

Both models report the same context window at 131.07K tokens.

Sample workload gpt-oss-20b (free) $0 vs $2

gpt-oss-20b (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

gpt-oss-20b (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

gpt-oss-20b (free) has the lower input price; gpt-oss-20b (free) has the lower output price; both models report the same context window. For the 1M input plus 500K output sample, gpt-oss-20b (free) is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0 for gpt-oss-20b (free) and $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview).

Best Fit

Choose gpt-oss-20b (free) when you care most about lower input-token price, and lower output-token price.

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, gpt-oss-20b (free) is estimated at $0 vs $2 for Nano Banana 2 (Gemini 3.1 Flash Image Preview), saving $2 (100% lower).
gpt-oss-20b (free) is free for the standard workload while the other model is estimated at $2.
gpt-oss-20b (free) is free for input tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $0.5 per 1M tokens.
gpt-oss-20b (free) is free for output tokens while Nano Banana 2 (Gemini 3.1 Flash Image Preview) costs $3 per 1M tokens.
Both models report the same context window at 131.07K tokens.

Head-to-Head Specs

Feature	gpt-oss-20b (free) (OpenAI)	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	131.07K	131.07K
Release Date	2025-08-05	2026-02-26
Popularity	#72	#129

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	gpt-oss-20b (free)	On the standard 1M input plus 500K output workload, gpt-oss-20b (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	gpt-oss-20b (free)	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	gpt-oss-20b (free)	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Tie	A 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 Nano Banana 2 (Gemini 3.1 Flash Image Preview) when lower sample workload cost matters most: $0.
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 Clip Preview 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.

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.

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Provider catalogs

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OpenAI catalog

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Google catalog

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Open Google models

gpt-oss-20b (free)

gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license. It uses a Mixture-of-Experts (MoE) architecture with 3.6B active parameters per forward pass, optimized for...

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...