Google: Nano Banana Pro (Gemini 3 Pro Image) vs OpenAI: o3 Mini High
Neither wins outright: Google: Nano Banana Pro (Gemini 3 Pro Image) is the pick when you need image input, OpenAI: o3 Mini High when cost matters at scale.
Monthly cost at list price for five common workloads. Token counts per unit are stated so you can scale them to your own traffic. A workload that does not fit a model's context window is marked rather than priced.
Workload (per month)
Google: Nano Banana Pro (Gemini 3 Pro Image)
OpenAI: o3 Mini High
Difference
Customer-support chatbot
50,000 conversations — each a 6-turn conversation (1,500 in / 400 out tokens)
$390
$171
OpenAI: o3 Mini High saves $220
RAG search over documents
20,000 questions — each a question answered from ~8 retrieved passages (6,000 in / 500 out tokens)
$360
$176
OpenAI: o3 Mini High saves $184
Coding / tool-using agent
2,000 tasks — each a multi-step task with tool calls and file context (60,000 in / 6,000 out tokens)
$384
$185
OpenAI: o3 Mini High saves $199
Batch summarisation
10,000 documents — each a 6,000-word report summarised to a page (8,000 in / 600 out tokens)
$232
$114
OpenAI: o3 Mini High saves $118
Long-document analysis
500 documents — each a 150-page contract or codebase read in one pass (100,000 in / 2,000 out tokens)
$112
$59.40
OpenAI: o3 Mini High saves $52.60
Capabilities side by side
Capability
Google: Nano Banana Pro (Gemini 3 Pro Image)
OpenAI: o3 Mini High
What it lets you do
Tool / function calling
✓ Yes
✓ Yes
call your APIs and run agent loops
Structured output (JSON schema)
✓ Yes
✓ Yes
return JSON that validates against your schema
Reasoning / thinking mode
✓ Yes
✓ Yes
spend extra tokens thinking before answering hard problems
Image input
✓ Yes
—
read screenshots, charts and scanned pages
Audio input
—
—
take speech or audio directly
File / PDF input
—
✓ Yes
accept documents without your own parsing step
Image output
✓ Yes
—
generate images, not just text
Built-in web search
✓ Yes
✓ Yes
answer from live web results
Seed (reproducible sampling)
✓ Yes
✓ Yes
repeat a generation for tests and evals
Log-probabilities
—
—
read token confidence for classification and scoring
From each model's published parameters and input/output types. “—” means not advertised, not proven absent.
Price history
Google: Nano Banana Pro (Gemini 3 Pro Image): price unchanged since we started tracking it on 2026-08-06.
OpenAI: o3 Mini High: price unchanged since we started tracking it on 2026-03-10.
Which should you choose?
Choose Google: Nano Banana Pro (Gemini 3 Pro Image) if…
you need image input — to read screenshots, charts and scanned pages; OpenAI: o3 Mini High does not advertise it
you need image output — to generate images, not just text; OpenAI: o3 Mini High does not advertise it
you want the newer model — released 2026-06-18, 16 months after the other
Choose OpenAI: o3 Mini High if…
cost matters at scale — it is 57% cheaper on a typical 3:1 input/output mix ($171 vs $390 a month for 50,000 support chats)
you need to fit long inputs in one request — 200K tokens is roughly 300 pages, against 197
you need file / PDF input — to accept documents without your own parsing step; Google: Nano Banana Pro (Gemini 3 Pro Image) does not advertise it
you generate long outputs in one go — up to 100K tokens (about 75,000 words) per response
Frequently asked questions
Is Google: Nano Banana Pro (Gemini 3 Pro Image) better than OpenAI: o3 Mini High?
Neither wins outright: Google: Nano Banana Pro (Gemini 3 Pro Image) is the pick when you need image input, OpenAI: o3 Mini High when cost matters at scale. In short: Google: Nano Banana Pro (Gemini 3 Pro Image) when you need image input, you need image output, you want the newer model; OpenAI: o3 Mini High when cost matters at scale, you need to fit long inputs in one request, you need file / PDF input, you generate long outputs in one go.
Which is cheaper, Google: Nano Banana Pro (Gemini 3 Pro Image) or OpenAI: o3 Mini High?
OpenAI: o3 Mini High is cheaper: $1.93 vs $4.50 per 1M tokens at a typical 3:1 input/output mix, 57% less. For 50,000 support conversations a month that is $171 against $390.
How much do Google: Nano Banana Pro (Gemini 3 Pro Image) and OpenAI: o3 Mini High cost per million tokens?
Google: Nano Banana Pro (Gemini 3 Pro Image) costs $2.00 per 1M input tokens and $12.00 per 1M output tokens; OpenAI: o3 Mini High costs $1.10 input and $4.40 output. Output tokens are billed separately, so long answers shift the gap.
Which has the bigger context window, Google: Nano Banana Pro (Gemini 3 Pro Image) or OpenAI: o3 Mini High?
OpenAI: o3 Mini High: 200K tokens, about 300 pages, against 131K (about 197 pages) for Google: Nano Banana Pro (Gemini 3 Pro Image).
Do Google: Nano Banana Pro (Gemini 3 Pro Image) and OpenAI: o3 Mini High support function calling and JSON output?
Tool calling — Google: Nano Banana Pro (Gemini 3 Pro Image): yes, OpenAI: o3 Mini High: yes. JSON-schema structured output — Google: Nano Banana Pro (Gemini 3 Pro Image): yes, OpenAI: o3 Mini High: yes.
Can Google: Nano Banana Pro (Gemini 3 Pro Image) or OpenAI: o3 Mini High read images?
Only Google: Nano Banana Pro (Gemini 3 Pro Image) accepts image input; OpenAI: o3 Mini High is text-only for input.
Is Google: Nano Banana Pro (Gemini 3 Pro Image) or OpenAI: o3 Mini High free to use?
No free variant is listed for either; both are pay-per-token.
What is the maximum output length of Google: Nano Banana Pro (Gemini 3 Pro Image) and OpenAI: o3 Mini High?
Google: Nano Banana Pro (Gemini 3 Pro Image) can write up to 33K tokens (about 24,600 words) per response; OpenAI: o3 Mini High up to 100K (about 75,000 words).
When were Google: Nano Banana Pro (Gemini 3 Pro Image) and OpenAI: o3 Mini High released?
Google: Nano Banana Pro (Gemini 3 Pro Image) was listed on 2026-06-18; OpenAI: o3 Mini High on 2025-02-12.
Nano Banana Pro is Google’s most advanced image-generation and editing model, built on Gemini 3 Pro. It extends the original Nano Banana with significantly improved multimodal reasoning, real-world grounding, and...
OpenAI o3-mini-high is the same model as [o3-mini](/openai/o3-mini) with reasoning_effort set to high. o3-mini is a cost-efficient language model optimized for STEM reasoning tasks, particularly excelling in science, mathematics, and...