Gemini 3.5 Flash-Lite vs o4-mini
Google against OpenAI, costed on the same three workloads. Gemini 3.5 Flash-Lite is cheaper on all three workloads.
o4-mini has been retired by its vendor. Its column shows the last rates it was sold at, kept for reference.
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Monthly bill, side by side
| Workload | Gemini 3.5 Flash-Lite | o4-mini | Difference |
|---|---|---|---|
| Support chatbot 2,500 six-turn conversations a day |
$1,613 | $3,985 | $2,371 (2.5×) |
| Document summarizer 1,000 single-shot summaries a day |
$170 | $508 | $338 (3×) |
| Coding agent 200 twelve-turn sessions a day |
$1,022 | $2,891 | $1,868 (2.8×) |
No prompt caching and no batch discount on either side, so the comparison is like for like. Both figures assume 30 days a month.
The rate cards
| Gemini 3.5 Flash-Lite | o4-mini | |
|---|---|---|
| Input, per 1M tokens | $0.3 | $1.1 |
| Output, per 1M tokens | $2.5 | $4.4 |
| Cached input | $0.03 | $0.275 |
| Context window | 1.05M | 200K |
| Maximum output | 66K | 100K |
| Reasoning model | yes | yes |
| Vision | yes | yes |
Beyond the price
- Gemini 3.5 Flash-Lite reads up to 1.05M tokens of context in one request; o4-mini stops at 200K.
- o4-mini can write up to 100K tokens in one response, against 66K for Gemini 3.5 Flash-Lite.
- Cached input costs 90% less than fresh input on Gemini 3.5 Flash-Lite and 75% less on o4-mini, which matters most for workloads that resend the same prompt.
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Full detail: Gemini 3.5 Flash-Lite pricing · o4-mini pricing
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Common questions
Which is cheaper, Gemini 3.5 Flash-Lite or o4-mini?
Gemini 3.5 Flash-Lite is cheaper on all three workloads.
How much would Gemini 3.5 Flash-Lite and o4-mini cost each month?
On PromptSpend's standard workloads, per month: support chatbot: Gemini 3.5 Flash-Lite $1,613, o4-mini $3,985 (Gemini 3.5 Flash-Lite is cheaper by $2,371); document summarizer: Gemini 3.5 Flash-Lite $170, o4-mini $508 (Gemini 3.5 Flash-Lite is cheaper by $338); coding agent: Gemini 3.5 Flash-Lite $1,022, o4-mini $2,891 (Gemini 3.5 Flash-Lite is cheaper by $1,868). No prompt caching and no batch discount is assumed.
How do Gemini 3.5 Flash-Lite and o4-mini differ apart from price?
Gemini 3.5 Flash-Lite reads up to 1.05M tokens of context in one request; o4-mini stops at 200K. o4-mini can write up to 100K tokens in one response, against 66K for Gemini 3.5 Flash-Lite. Cached input costs 90% less than fresh input on Gemini 3.5 Flash-Lite and 75% less on o4-mini, which matters most for workloads that resend the same prompt.