Google: Gemini 3 Flash Preview vs OpenAI: o3 Mini (batch)
Head-to-head API pricing and cost comparison between Google’s Google: Gemini 3 Flash Preview and OpenAI’s OpenAI: o3 Mini (batch). Prices auto-refresh daily from OpenRouter.
Google: Gemini 3 Flash Preview is 9% cheaper for input tokens; OpenAI: o3 Mini (batch) wins on output tokens at $2.20/1M.
Side-by-side comparison
| Spec | Google: Gemini 3 Flash Preview | OpenAI: o3 Mini (batch) |
|---|---|---|
| Input price (per 1M) | $0.50 | $0.55 |
| Cached input (per 1M) | $0.05 | $0.28 |
| Output price (per 1M) | $3.00 | $2.20 |
| Batch input (per 1M) | — | $0.28 |
| Batch output (per 1M) | — | $1.10 |
| Reasoning price (per 1M) | $3.00 | — |
| Context window | 1049K | 200K |
| Vision support | Yes | No |
| Caching support | Yes | Yes |
| Batch API | No | Yes |
| Reasoning capability | Yes | Yes |
Monthly cost at volume
Estimated monthly API spend at common production traffic levels (input/output tokens per request shown).
| Volume | Google: Gemini 3 Flash Preview | OpenAI: o3 Mini (batch) | Savings |
|---|---|---|---|
1K req/day 500in / 200out tokens | $25.50 | $21.45 | $4.05 OpenAI: o3 Mini (batch) wins |
10K req/day 1500in / 500out tokens | $675.00 | $577.50 | $97.50 OpenAI: o3 Mini (batch) wins |
100K req/day 3000in / 800out tokens | $11,700 | $10,230 | $1,470 OpenAI: o3 Mini (batch) wins |
1M req/day 8000in / 2000out tokens | $300,000 | $264,000 | $36,000 OpenAI: o3 Mini (batch) wins |
Adjust input/output token counts, request volume, batch & cached pricing.
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Frequently asked questions
Which is cheaper, Google: Gemini 3 Flash Preview or OpenAI: o3 Mini (batch)?
For input tokens, Google: Gemini 3 Flash Preview is roughly 9% cheaper at $0.50/1M vs $0.55/1M. For output tokens, OpenAI: o3 Mini (batch) wins at $2.20/1M. Real-world cost depends on your input/output ratio — use the calculator to model your actual workload.
What’s the context window difference?
Google: Gemini 3 Flash Preview has a context window of 1049K tokens. OpenAI: o3 Mini (batch) offers 200K tokens. Larger context windows are valuable for long documents, RAG pipelines, and multi-turn conversations — but they come with higher input-token bills if you fill them every request.
Should I use Google: Gemini 3 Flash Preview or OpenAI: o3 Mini (batch)?
Choose Google: Gemini 3 Flash Preview if you’re already on the Google stack, want reasoning capabilities, or prefer its lower input price. Choose OpenAI: o3 Mini (batch) for OpenAI’s ecosystem, or its cheaper output tokens. Run a small benchmark on your own prompts before committing — price is only one axis.
How are these prices kept current?
Prices are pulled directly from OpenRouter’s public models API once every 24 hours via a Convex cron job, then normalized to per-1M-token figures. Last refresh: Sep 16, 2026.