# Gemini 2.5 Flash vs Gemini 3.8 Flash

Gemini 3.8 Flash is one of Google's newest models and Gemini 2.5 Flash an earlier one, so this is also what moving up costs or saves. Gemini 2.5 Flash is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Gemini 3.8 Flash costs 1.8 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-2-5-flash-vs-gemini-3-8-flash
- Makers: Gemini 2.5 Flash from Google, Gemini 3.8 Flash from Google

## Price per million tokens, in US dollars

| | Gemini 2.5 Flash | Gemini 3.8 Flash |
| --- | --: | --: |
| Input | $0.30 | $0.75 |
| Cached input | $0.03 | $0.075 |
| Cache write | not listed | not listed |
| Output | $2.50 | $3.75 |
| Blend, 3 read for each 1 written | $0.85 | $1.50 |
| 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) | not listed | 157 |
| Longest answer, tokens | 66K | 66K |

Gemini 2.5 Flash: Audio input is $1.

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

## 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 2.5 Flash | Gemini 3.8 Flash |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $4.02 | $6.30 |
| A hard question, with thinking | 300, 1,400, 100 | $10.77 | $16.43 |
| A long report, summarised | 60,000, 2,000, 20 | $13.80 | $31.50 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $77.88 | $165 |
| A support bot's reply | 4,000, 300, 2,000 | $84.60 | $166 |
| Sort a message into a category | 250, 5, 50,000 | $131 | $309 |
| Read an invoice into fields | 1,500, 250, 1,000 | $32.25 | $61.88 |
| Review a pull request | 25,000, 4,500, 50 | $28.13 | $53.44 |

## Questions

### Which is cheaper, Gemini 2.5 Flash or Gemini 3.8 Flash?

Gemini 2.5 Flash is cheaper: $0.30 per million tokens read and $2.50 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 1.8 times as much.

### Which is better, Gemini 2.5 Flash or Gemini 3.8 Flash?

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 2.5 Flash 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 2.5 Flash and Gemini 3.8 Flash?

At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $84.60 a month on Gemini 2.5 Flash and $166 on Gemini 3.8 Flash: Gemini 3.8 Flash costs 2 times as much for this job.

### What does an AI agent task cost on Gemini 2.5 Flash and Gemini 3.8 Flash?

One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs 26 cents on Gemini 2.5 Flash and 55 cents on Gemini 3.8 Flash. At 10 tasks a day that is $77.88 and $165 a month.

### Which has the larger context window, Gemini 2.5 Flash or Gemini 3.8 Flash?

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 2.5 Flash and Gemini 3.8 Flash?

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 2.5 Flash 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 $0.30 and $2.50 on Gemini 2.5 Flash, 1.8 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 2.5 Flash and Gemini 3.8 Flash 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)
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- [Gemini 3.8 Flash vs Gemini 3 Flash Preview](https://tecyfy.com/prices/compare/gemini-3-8-flash-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)
- [Gemini 2.5 Flash vs Gemini 4 Argon](https://tecyfy.com/prices/compare/gemini-2-5-flash-vs-gemini-4-argon.md)