API cost decision in 10 seconds

Nano Banana (Gemini 2.5 Flash Image) vs GPT-5.1-Codex-Mini

Pick GPT-5.1-Codex-Mini 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-5.1-Codex-Mini when budget and context both matter.

On the standard 1M input plus 500K output workload, GPT-5.1-Codex-Mini is estimated at $1.25 vs $1.55 for Nano Banana (Gemini 2.5 Flash Image), saving $0.3 (19.4% lower).

Cost-first pickGPT-5.1-Codex-Mini
Context-first pickGPT-5.1-Codex-Mini
Sample savings$0.319.4%
10x traffic gap$3

GPT-5.1-Codex-Mini is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $3. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

GPT-5.1-Codex-Mini stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickNano Banana (Gemini 2.5 Flash Image)GPT-5.1-Codex-Mini
Input-heavy / RAG5M input + 500K outputGPT-5.1-Codex-Mini$2.75$2.25
Balanced workload1M input + 1M outputGPT-5.1-Codex-Mini$2.8$2.25
Output-heavy chatbot1M input + 5M outputGPT-5.1-Codex-Mini$12.8$10.25
Cheaper input GPT-5.1-Codex-Mini $0.3 vs $0.25 / 1M

GPT-5.1-Codex-Mini is $0.05 cheaper per 1M input tokens (16.7% lower; 1.2x difference).

Cheaper output GPT-5.1-Codex-Mini $2.5 vs $2 / 1M

GPT-5.1-Codex-Mini is $0.5 cheaper per 1M output tokens (20% lower; 1.25x difference).

Larger context GPT-5.1-Codex-Mini 32.77K vs 400K

GPT-5.1-Codex-Mini has 367.23K more context (12.2x larger).

Sample workload GPT-5.1-Codex-Mini $1.55 vs $1.25

GPT-5.1-Codex-Mini is $0.3 cheaper on the standard workload (19.4% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
Nano Banana (Gemini 2.5 Flash Image) Calculating… Estimated API cost
GPT-5.1-Codex-Mini 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-5.1-Codex-Mini has the lower input price; GPT-5.1-Codex-Mini has the lower output price; GPT-5.1-Codex-Mini offers the larger context window. For the 1M input plus 500K output sample, GPT-5.1-Codex-Mini is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $1.55 for Nano Banana (Gemini 2.5 Flash Image) and $1.25 for GPT-5.1-Codex-Mini.

Best Fit

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.

Choose GPT-5.1-Codex-Mini when you care most about lower input-token price, lower output-token price, and larger context window.

Decision Notes
  • On the standard 1M input plus 500K output workload, GPT-5.1-Codex-Mini is estimated at $1.25 vs $1.55 for Nano Banana (Gemini 2.5 Flash Image), saving $0.3 (19.4% lower).
  • GPT-5.1-Codex-Mini is $0.3 cheaper on the standard workload (19.4% lower).
  • GPT-5.1-Codex-Mini is $0.05 cheaper per 1M input tokens (16.7% lower; 1.2x difference).
  • GPT-5.1-Codex-Mini is $0.5 cheaper per 1M output tokens (20% lower; 1.25x difference).
  • GPT-5.1-Codex-Mini has 367.23K more context (12.2x larger).
Head-to-Head Specs
FeatureNano Banana (Gemini 2.5 Flash Image)
(Google)		GPT-5.1-Codex-Mini
(OpenAI)
Input Price
prompt tokens per 1M		$0.3$0.25
Completion Price
per 1M tokens		$2.5$2
Sample Workload Cost
1M input + 500K output		$1.55$1.25
Context Window32.77K400K
Release Date
Popularity#121#141

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGPT-5.1-Codex-MiniOn the standard 1M input plus 500K output workload, GPT-5.1-Codex-Mini is estimated at $1.25 vs $1.55 for Nano Banana (Gemini 2.5 Flash Image), saving $0.3 (19.4% lower).
High-volume input processingGPT-5.1-Codex-MiniLower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsGPT-5.1-Codex-MiniLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGPT-5.1-Codex-MiniA 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 (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.
  • Lyria 3 Clip Preview can replace Nano Banana (Gemini 2.5 Flash Image) when lower sample workload cost matters most: $0.
  • Lyria 3 Pro Preview can replace Nano Banana (Gemini 2.5 Flash Image) when lower sample workload cost matters most: $0.
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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,...

GPT-5.1-Codex-Mini

GPT-5.1-Codex-Mini is a smaller and faster version of GPT-5.1-Codex