# Gemini 3.8 Flash vs Gemini 3 Flash Preview

Gemini 3.8 Flash is one of Google's newest models and Gemini 3 Flash Preview an earlier one, so this is also what moving up costs or saves. Gemini 3 Flash Preview is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Gemini 3.8 Flash costs 1.3 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-3-8-flash-vs-gemini-3-flash-preview
- Makers: Gemini 3.8 Flash from Google, Gemini 3 Flash Preview from Google

## Price per million tokens, in US dollars

| | Gemini 3.8 Flash | Gemini 3 Flash Preview |
| --- | --: | --: |
| Input | $0.75 | $0.50 |
| Cached input | $0.075 | $0.05 |
| Cache write | not listed | not listed |
| Output | $3.75 | $3 |
| Blend, 3 read for each 1 written | $1.50 | $1.125 |
| 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) | 157 | not listed |
| Longest answer, tokens | 66K | 66K |

Gemini 3.8 Flash: Until 31 December 2026. From 1 January 2027 it is $1.50 in, $7.50 out and $0.15 cached.

Gemini 3 Flash Preview: Audio input is $1.

## 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 3.8 Flash | Gemini 3 Flash Preview |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $6.30 | $4.95 |
| A hard question, with thinking | 300, 1,400, 100 | $16.43 | $13.05 |
| A long report, summarised | 60,000, 2,000, 20 | $31.50 | $21.60 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $165 | $116 |
| A support bot's reply | 4,000, 300, 2,000 | $166 | $120 |
| Sort a message into a category | 250, 5, 50,000 | $309 | $210 |
| Read an invoice into fields | 1,500, 250, 1,000 | $61.88 | $45.00 |
| Review a pull request | 25,000, 4,500, 50 | $53.44 | $39.00 |

## Questions

### Which is cheaper, Gemini 3.8 Flash or Gemini 3 Flash Preview?

Gemini 3 Flash Preview is cheaper: $0.50 per million tokens read and $3 per million written, against $0.75 and $3.75 on Gemini 3.8 Flash. On a mix of 3 tokens read for each 1 written, Gemini 3.8 Flash costs 1.3 times as much.

### Which is better, Gemini 3.8 Flash or Gemini 3 Flash Preview?

Gemini 3.8 Flash scores 157 on the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks (GPT-5 is 150). Gemini 3 Flash Preview has no independent score yet, so the only fair test is to run the same 10 tasks on both.

### What does a support bot cost a month on Gemini 3.8 Flash and Gemini 3 Flash Preview?

At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $166 a month on Gemini 3.8 Flash and $120 on Gemini 3 Flash Preview: Gemini 3.8 Flash costs 1.4 times as much for this job.

### What does an AI agent task cost on Gemini 3.8 Flash and Gemini 3 Flash Preview?

One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs 55 cents on Gemini 3.8 Flash and 39 cents on Gemini 3 Flash Preview. At 10 tasks a day that is $165 and $116 a month.

### Which has the larger context window, Gemini 3.8 Flash or Gemini 3 Flash Preview?

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 3.8 Flash and Gemini 3 Flash Preview?

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 Flash Preview to Gemini 3.8 Flash?

No, it costs more per token: Gemini 3.8 Flash charges $0.75 per million tokens read and $3.75 written, against $0.50 and $3 on Gemini 3 Flash Preview, 1.3 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 3.8 Flash and Gemini 3 Flash Preview 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)

## Other comparisons

- [Gemini 3.6 Flash vs Gemini 3.8 Flash](https://tecyfy.com/prices/compare/gemini-3-6-flash-vs-gemini-3-8-flash.md)
- [Gemini 3.1 Pro Preview vs Gemini 3.8 Flash](https://tecyfy.com/prices/compare/gemini-3-1-pro-preview-vs-gemini-3-8-flash.md)
- [Gemini 3.1 Flash-Lite vs Gemini 3.8 Flash](https://tecyfy.com/prices/compare/gemini-3-1-flash-lite-vs-gemini-3-8-flash.md)
- [Gemini 3 Flash Preview vs Gemini 4 Argon](https://tecyfy.com/prices/compare/gemini-3-flash-preview-vs-gemini-4-argon.md)
- [Gemini 3.5 Flash-Lite vs Gemini 3 Flash Preview](https://tecyfy.com/prices/compare/gemini-3-5-flash-lite-vs-gemini-3-flash-preview.md)
- [Gemini 2.5 Pro vs Gemini 3.8 Flash](https://tecyfy.com/prices/compare/gemini-2-5-pro-vs-gemini-3-8-flash.md)