Gemini 3.1 Pro Preview API pricing
Official Google list price, last checked Oct 29, 2026. Updated Oct 29, 2026.
Gemini 3.1 Pro Preview costs $2 per 1M input tokens and $12 per 1M output tokens, cached input at $0.20, per Google's official pricing page (checked Oct 29, 2026). It's a premium-priced model: number 67 of 77 by blended price ($4.50 per 1M tokens at a 3 to 1 input to output mix). On LMArena's Code Arena it ranks #39 of 50 models we price (relative score 0 out of 100). Cheaper pick: DeepSeek V4.1 Flash scores 46 against 0 on the same board at $0.525 blended, 8.6x less.
Gemini 3.1 Pro Preview price per million tokens
| Gemini 3.1 Pro Preview price per million tokens | USD |
|---|---|
| Input | $2 |
| Cached input | $0.20 |
| Output | $12 |
| Blended, 3 parts input to 1 part output | $4.50 |
| Context window | Not listed |
| Prompts above 200K | $4 in, $18 out |
Official note from Google: Prompts up to 200K. Longer prompts cost $4 in, $18 out.
What Gemini 3.1 Pro Preview costs for real work
List-price estimates for a month, no discounts. Our math, not a quote: change the token counts in the plan vs API calculator.
| Workload | Tokens a month | Gemini 3.1 Pro Preview | GPT-5.6 Terra | GPT-6.1 Terra |
|---|---|---|---|---|
| Light: a side project or personal assistant | 2M in, 0.5M out | $10.00 | $10.00 | $4.50 |
| Medium: a small team or one product feature | 20M in, 5M out | $100 | $100 | $45.00 |
| Heavy: a production app | 200M in, 50M out | $1,000 | $1,000 | $450 |
| Medium with 80% of input cached | 20M in (16M cached), 5M out | $71.20 | $71.20 | $29.80 |
| Medium, every prompt above the long-prompt threshold | 20M in, 5M out | $170 | $100 | $77.50 |
How Gemini 3.1 Pro Preview ranks on LMArena
Relative score: 100 is the top model we price on that board. Rank is among the models in our price table, not the full leaderboard.
| Board | Rank | Score /100 |
|---|---|---|
| Coding (Code Arena) | #39 of 50 | 0 |
| Chat (Text Arena) | #9 of 51 | 37 |
| Creative writing (Text Arena creative writing) | #6 of 51 | 48 |
| Roleplay and characters (Text Arena multi-turn) | #6 of 51 | 32 |
| Reasoning and math (Text Arena math) | #19 of 51 | 23 |
| Vision (Vision Arena) | #11 of 33 | 54 |
| Long documents (Document Arena) | #8 of 11 | 63 |
| Cheap bulk and agents (Agent Arena) | #27 of 34 | 33 |
Closest rivals to Gemini 3.1 Pro Preview
The models nearest in price, other makers first. Ranks are on Code Arena, where we have them.
| Model | In / out | Blended | Verdict |
|---|---|---|---|
| GPT-5.6 Terra | $2 / $12 | $4.50 | Same price, no score to separate them. Compare |
| GPT-6.1 Sol | $2 / $10 | $4 | GPT-6.1 Sol wins on both. Compare |
| GPT-6 Sol | $2 / $10 | $4 | GPT-6 Sol wins on both. Compare |
| Claude Sonnet 5.5 | $2 / $10 | $4 | Claude Sonnet 5.5 wins on both. Compare |
Cheaper alternatives to Gemini 3.1 Pro Preview
At least 40% cheaper blended, best LMArena score first.
| Model | In / out | Blended | Verdict |
|---|---|---|---|
| GPT-6.1 Terra | $1 / $5 | $2 | GPT-6.1 Terra wins on both. Compare |
| DeepSeek V4.1 Flash | $0.30 / $1.20 | $0.525 | DeepSeek V4.1 Flash wins on both. Compare |
| Muse Spark 1.3 | $1.25 / $4.25 | $2 | Muse Spark 1.3 wins on both. Compare |
More from Google
- Gemini 4 Argon$2 in, $10 out per 1M
- Gemini 3.8 Flash$0.75 in, $3.75 out per 1M
- Gemini 3.5 Flash-Lite$0.30 in, $2.50 out per 1M
FAQ
How much does the Gemini 3.1 Pro Preview API cost per million tokens?
$2 per 1M input tokens and $12 per 1M output tokens, plus $0.20 per 1M for cached input, as of Oct 29, 2026. A typical 3 to 1 input to output mix works out to $4.50 per 1M tokens.
Does Gemini 3.1 Pro Preview charge more for long prompts?
Yes. Prompts above 200K: $4 in, $18 out.
Is Gemini 3.1 Pro Preview cheaper than GPT-5.6 Terra?
About the same. A medium month (20M input and 5M output tokens) costs $100 on Gemini 3.1 Pro Preview and $100 on GPT-5.6 Terra at list price. On Code Arena, Gemini 3.1 Pro Preview ranks #39 and GPT-5.6 Terra isn't ranked.
How does Gemini 3.1 Pro Preview rank on LMArena?
On Code Arena it is #39 of 50 models we price, with a relative score of 0 out of 100. It ranks on 8 of 8 boards we track.
What is a cheaper alternative to Gemini 3.1 Pro Preview?
GPT-6.1 Terra costs $1 in and $5 out per 1M tokens, about 2.2x less blended, and scores 49 on Code Arena against 0 for Gemini 3.1 Pro Preview.
Where does this Gemini 3.1 Pro Preview price come from?
From Google's official pricing page, which we check every day. This page was last checked Oct 29, 2026.