API cost decision in 10 seconds

gpt-oss-20b vs Nano Banana (Gemini 2.5 Flash Image)

Pick gpt-oss-20b when budget and context both matter.

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

Budget verdict

Pick gpt-oss-20b when budget and context both matter.

On the standard 1M input plus 500K output workload, gpt-oss-20b is estimated at $0.1 vs $1.55 for Nano Banana (Gemini 2.5 Flash Image), saving $1.45 (93.5% lower).

Cost-first pickgpt-oss-20b
Context-first pickgpt-oss-20b
Sample savings$1.4593.5%
10x traffic gap$14.5

gpt-oss-20b is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $14.5. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

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

Workload shapeToken mixBetter pickgpt-oss-20bNano Banana (Gemini 2.5 Flash Image)
Input-heavy / RAG5M input + 500K outputgpt-oss-20b$0.22$2.75
Balanced workload1M input + 1M outputgpt-oss-20b$0.17$2.8
Output-heavy chatbot1M input + 5M outputgpt-oss-20b$0.73$12.8
Cheaper input gpt-oss-20b $0.03 vs $0.3 / 1M

gpt-oss-20b is $0.27 cheaper per 1M input tokens (90% lower; 10x difference).

Cheaper output gpt-oss-20b $0.14 vs $2.5 / 1M

gpt-oss-20b is $2.36 cheaper per 1M output tokens (94.4% lower; 17.9x difference).

Larger context gpt-oss-20b 131.07K vs 32.77K

gpt-oss-20b has 98.3K more context (4x larger).

Sample workload gpt-oss-20b $0.1 vs $1.55

gpt-oss-20b is $1.45 cheaper on the standard workload (93.5% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
gpt-oss-20b Calculating… Estimated API cost
Nano Banana (Gemini 2.5 Flash Image) 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 has the lower input price; gpt-oss-20b has the lower output price; gpt-oss-20b offers the larger context window. For the 1M input plus 500K output sample, gpt-oss-20b is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0.1 for gpt-oss-20b and $1.55 for Nano Banana (Gemini 2.5 Flash Image).

Best Fit

Choose gpt-oss-20b when you care most about lower input-token price, lower output-token price, and larger context window.

Choose Nano Banana (Gemini 2.5 Flash Image) 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 is estimated at $0.1 vs $1.55 for Nano Banana (Gemini 2.5 Flash Image), saving $1.45 (93.5% lower).
  • gpt-oss-20b is $1.45 cheaper on the standard workload (93.5% lower).
  • gpt-oss-20b is $0.27 cheaper per 1M input tokens (90% lower; 10x difference).
  • gpt-oss-20b is $2.36 cheaper per 1M output tokens (94.4% lower; 17.9x difference).
  • gpt-oss-20b has 98.3K more context (4x larger).
Head-to-Head Specs
Featuregpt-oss-20b
(OpenAI)		Nano Banana (Gemini 2.5 Flash Image)
(Google)
Input Price
prompt tokens per 1M		$0.03$0.3
Completion Price
per 1M tokens		$0.14$2.5
Sample Workload Cost
1M input + 500K output		$0.1$1.55
Context Window131.07K32.77K
Release Date
Popularity#67#121

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productiongpt-oss-20bOn the standard 1M input plus 500K output workload, gpt-oss-20b is estimated at $0.1 vs $1.55 for Nano Banana (Gemini 2.5 Flash Image), saving $1.45 (93.5% lower).
High-volume input processinggpt-oss-20bLower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsgpt-oss-20bLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workgpt-oss-20bA larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • gpt-oss-120b (free) can replace gpt-oss-20b when lower sample workload cost matters most: $0.
  • gpt-oss-20b (free) can replace gpt-oss-20b when lower sample workload cost matters most: $0.
  • Gemma 4 31B (free) can replace Nano Banana (Gemini 2.5 Flash Image) when lower sample workload cost matters most: $0.
  • Gemma 4 26B A4B (free) can replace Nano Banana (Gemini 2.5 Flash Image) when lower sample workload cost matters most: $0.
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Provider catalogs

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OpenAI catalog

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Google catalog

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gpt-oss-20b

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 (Gemini 2.5 Flash Image)

Gemini 2.5 Flash Image, a.k.a. "Nano Banana," is now generally available. It is a state of the art image generation model with contextual understanding. It is capable of image generation,...