# Gemini 3.1 Flash-Lite vs Gemini 3.5 Flash-Lite

Gemini 3.5 Flash-Lite is one of Google's newest models and Gemini 3.1 Flash-Lite an earlier one, so this is also what moving up costs or saves. Gemini 3.1 Flash-Lite is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Gemini 3.5 Flash-Lite costs 1.5 times as much. Below are both price lists, what 8 everyday jobs cost a month on each, and how many tokens the same text takes on each, which can change the answer.

- Page, with a calculator for your own job: https://tecyfy.com/prices/compare/gemini-3-1-flash-lite-vs-gemini-3-5-flash-lite
- Makers: Gemini 3.1 Flash-Lite from Google, Gemini 3.5 Flash-Lite from Google

## Price per million tokens, in US dollars

| | Gemini 3.1 Flash-Lite | Gemini 3.5 Flash-Lite |
| --- | --: | --: |
| Input | $0.25 | $0.30 |
| Cached input | $0.025 | $0.03 |
| Cache write | not listed | not listed |
| Output | $1.50 | $2.50 |
| Blend, 3 read for each 1 written | $0.5625 | $0.85 |
| Batch input | not listed | not listed |
| Batch output | not listed | not listed |
| Context window, tokens | 1.05M | 1.05M |
| Capability score (Epoch Capabilities Index; GPT-5 is 150) | 144 | 145 |
| Longest answer, tokens | 66K | 66K |

Gemini 3.1 Flash-Lite: Audio input is $0.50.

## What 8 everyday jobs cost a month on each

Each job at its usual runs a day, for 30 days, at the standard price.

| Job | Tokens in, out, runs a day | Gemini 3.1 Flash-Lite | Gemini 3.5 Flash-Lite |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $2.48 | $4.02 |
| A hard question, with thinking | 300, 1,400, 100 | $6.52 | $10.77 |
| A long report, summarised | 60,000, 2,000, 20 | $10.80 | $13.80 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $57.90 | $77.88 |
| A support bot's reply | 4,000, 300, 2,000 | $60.00 | $84.60 |
| Sort a message into a category | 250, 5, 50,000 | $105 | $131 |
| Read an invoice into fields | 1,500, 250, 1,000 | $22.50 | $32.25 |
| Review a pull request | 25,000, 4,500, 50 | $19.50 | $28.13 |

## Questions

### Which is cheaper, Gemini 3.1 Flash-Lite or Gemini 3.5 Flash-Lite?

Gemini 3.1 Flash-Lite is cheaper: $0.25 per million tokens read and $1.50 per million written, against $0.30 and $2.50 on Gemini 3.5 Flash-Lite. On a mix of 3 tokens read for each 1 written, Gemini 3.5 Flash-Lite costs 1.5 times as much.

### Which is better, Gemini 3.1 Flash-Lite or Gemini 3.5 Flash-Lite?

They cannot be told apart on the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks: Gemini 3.1 Flash-Lite scores 144 and Gemini 3.5 Flash-Lite 145, within the range of doubt around each (GPT-5 is 150). So choose on price and on 10 tasks of your own.

### What does a support bot cost a month on Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite?

At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $60.00 a month on Gemini 3.1 Flash-Lite and $84.60 on Gemini 3.5 Flash-Lite: Gemini 3.5 Flash-Lite costs 1.4 times as much for this job.

### What does an AI agent task cost on Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite?

One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs 19 cents on Gemini 3.1 Flash-Lite and 26 cents on Gemini 3.5 Flash-Lite. At 10 tasks a day that is $57.90 and $77.88 a month.

### Which has the larger context window, Gemini 3.1 Flash-Lite or Gemini 3.5 Flash-Lite?

Neither: both hold 1.05M tokens at once, about 1,572.9 pages of English text.

### Does the same text take the same number of tokens on Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite?

Yes, both are counted the same way: our lesson "How AI writes", 1,700 words long, is about 2,200 tokens on each.

### Is it cheaper to move from Gemini 3.1 Flash-Lite to Gemini 3.5 Flash-Lite?

No, it costs more per token: Gemini 3.5 Flash-Lite charges $0.30 per million tokens read and $2.50 written, against $0.25 and $1.50 on Gemini 3.1 Flash-Lite, 1.5 times as much for the same tokens. It pays off only if better answers save more than that, for example in fewer retries.

### Can I pay less on Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite for work that can wait?

Not with a batch price: neither maker's price page lists one for these models. A cache still lowers the price of text the model reads again.

## Sources

- [Google: API prices](https://ai.google.dev/gemini-api/docs/pricing)
- [Epoch Capabilities Index, by Epoch AI (CC BY 4.0)](https://epoch.ai/benchmarks/eci)

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