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.
- For the same tokens
- Gemini 3 Flash Preview is cheaper; Gemini 3.8 Flash costs 1.3 times as much
- Cheaper to read
- Gemini 3 Flash Preview, $0.50 against $0.75
- Cheaper to write
- Gemini 3 Flash Preview, $3 against $3.75
- Scores higher
- Not known, Gemini 3 Flash Preview has no independent score yet
- Larger window
- The same, 1.05M tokens each
Price per million tokens, side by side
In US dollars, as each maker prints them. The better figure in each row is green.
| Gemini 3.8 FlashGoogle | Gemini 3 Flash PreviewGoogle · earlier model | |
|---|---|---|
| InputTokens the model reads | $0.75 | $0.50 |
| Cached inputRead again from the cache | $0.075 | $0.05 |
| Cache writePutting text in the cache | Not listed | Not listed |
| OutputTokens it writes, thinking included | $3.75 | $3 |
| Blend 3:13 tokens read for each 1 written | $1.50 | $1.125 |
| Batch inputAnswers collected later | Not listed | Not listed |
| Batch output | Not listed | Not listed |
| Context windowTokens it holds at once | 1.05M | 1.05M |
| Capability scoreEpoch Capabilities Index; GPT-5 is 150 | 157 | Not listed |
| Longest answerTokens it writes in 1 reply | 66K | 66K |
Read before you choose
- 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 number of runs a day, for 30 days, at the standard price. The cheaper of the 2 is green; open any job in the calculator to change it.
| Job | Gemini 3.8 Flash | Gemini 3 Flash Preview | Difference |
|---|---|---|---|
| A chat question300 in, 500 out, 100 a day | $6.300.21 cents a run | $4.950.17 cents a run | 1.3 times |
| A hard question, with thinking300 in, 1,400 out, 100 a day | $16.430.55 cents a run | $13.050.43 cents a run | 1.3 times |
| A long report, summarised60,000 in, 2,000 out, 20 a day | $31.505.3 cents a run | $21.603.6 cents a run | 1.5 times |
| A 40-turn agent task2,800,000 in, 40,000 out, 10 a day | $16555 cents a run | $11639 cents a run | 1.4 times |
| A support bot's reply4,000 in, 300 out, 2,000 a day | $1660.28 cents a run | $1200.2 cents a run | 1.4 times |
| Sort a message into a category250 in, 5 out, 50,000 a day | $3090.021 cents a run | $2100.014 cents a run | 1.5 times |
| Read an invoice into fields1,500 in, 250 out, 1,000 a day | $61.880.21 cents a run | $45.000.15 cents a run | 1.4 times |
| Review a pull request25,000 in, 4,500 out, 50 a day | $53.443.6 cents a run | $39.002.6 cents a run | 1.4 times |
Your own job on both
Start from a job, then set its size, how often it runs and whether the answers can wait. Both bills follow every change.
A short question and a few paragraphs back.
about 230 words
Instructions or documents the model has read before cost far less the second time.
about 380 words
A month of this job
- Gemini 3.8 Flash$6.30
0.21 cents a run
- Gemini 3 Flash Preview$4.95
0.17 cents a run
Gemini 3 Flash Preview saves $1.35 a month; Gemini 3.8 Flash costs 1.3 times as much.
This job on every modelWhy the price per token is only the start
Every maker prints 2 main prices: one for the tokens a model reads (input) and one for the tokens it writes (output). On most current models writing costs 3 to 5 times as much as reading, so which model is cheaper can depend on the job. A job that reads a long document and writes a line pays mostly the input price; a chat that writes paragraphs pays mostly the output price. That is why each comparison prices 8 jobs and not one figure.
The same text is not the same number of tokens on every model. Each maker cuts text its own way, and Anthropic says its models from Claude 4.7 on produce about 30 percent more tokens for the same text than earlier ones. A model with the lower price per token can still send the larger bill, so each comparison counts one of our lessons the way both makers count it.
Discounts change the order too. Work that can wait costs half on a batch at the makers that offer one, and text read again from a cache costs a quarter of the input price or less on every current model here. The price table on each comparison shows who offers what.
Thinking is billed as output, and models differ in how much they think and how long they answer. A price list cannot show that. Before you switch, run the same 10 tasks on both models and compare the bills.
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