Which is cheaper, Gemini 3.8 Flash or Kimi K3?

Gemini 3.8 Flash is cheaper: $0.75 per million tokens read and $3.75 per million written, against $3 and $15 on Kimi K3. On a mix of 3 tokens read for each 1 written, Kimi K3 costs 4 times as much.

Which is better, Gemini 3.8 Flash or Kimi K3?

They cannot be told apart on the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks: Gemini 3.8 Flash scores 157 and Kimi K3 157, 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 3.8 Flash and Kimi K3?

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 $666 on Kimi K3: Kimi K3 costs 4 times as much for this job.

What does an AI agent task cost on Gemini 3.8 Flash and Kimi K3?

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 $2.20 on Kimi K3. At 10 tasks a day that is $165 and $659 a month.

Which has the larger context window, Gemini 3.8 Flash or Kimi K3?

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 Kimi K3?

No. Our lesson "How AI writes", 1,700 words long, is about 2,200 tokens on Gemini 3.8 Flash and 2,055 on Kimi K3. Each maker cuts text its own way, and every extra token is paid for at the model's price.

Can I pay less on Gemini 3.8 Flash and Kimi K3 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.

Gemini 3.8 Flash vs Kimi K3

Gemini 3.8 Flash is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Kimi K3 costs 4 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.

Price your own job Compare 2 other models

For the same tokens: Gemini 3.8 Flash is cheaper; Kimi K3 costs 4 times as much
Cheaper to read: Gemini 3.8 Flash, $0.75 against $3
Cheaper to write: Gemini 3.8 Flash, $3.75 against $15
Scores higher: Neither, 157 and 157 are within the range of doubt
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	Kimi K3Moonshot AI
InputTokens the model reads	$0.75	$3
Cached inputRead again from the cache	$0.075	$0.30
Cache writePutting text in the cache	Not listed	$3
OutputTokens it writes, thinking included	$3.75	$15
Blend 3:13 tokens read for each 1 written	$1.50	$6
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	157
Longest answerTokens it writes in 1 reply	66K	Not listed

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.

The same text, counted by each maker

A price per token means little until you know how many tokens your text is. Here is our lesson How AI writes, about 1,700 words of English, counted the way each maker counts it, and what it costs to send it once.

Gemini 3.8 Flash
about 2,200 tokens
Sent once: 0.16 cents at $0.75 per million
Google does not publish the Gemini tokenizer. Its rule is that a token is about 4 characters, so the count is the characters divided by 4.
Kimi K3
2,055 tokens
Sent once: 0.62 cents at $3 per million
Counted with the tokenizer Moonshot AI publishes with Kimi K3, the model its API serves.

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. Sizes are in tokens, and Gemini 3.8 Flash can need up to 1.1 times as many as Kimi K3 for the same words, so its bill for the same work can be up to that much higher.

Job	Gemini 3.8 Flash	Kimi K3	Difference
A chat question300 in, 500 out, 100 a day	$6.300.21 cents a run	$25.200.84 cents a run	4 times
A hard question, with thinking300 in, 1,400 out, 100 a day	$16.430.55 cents a run	$65.702.2 cents a run	4 times
A long report, summarised60,000 in, 2,000 out, 20 a day	$31.505.3 cents a run	$12621 cents a run	4 times
A 40-turn agent task2,800,000 in, 40,000 out, 10 a day	$16555 cents a run	$659$2.20 a run	4 times
A support bot's reply4,000 in, 300 out, 2,000 a day	$1660.28 cents a run	$6661.1 cents a run	4 times
Sort a message into a category250 in, 5 out, 50,000 a day	$3090.021 cents a run	$1,2380.083 cents a run	4 times
Read an invoice into fields1,500 in, 250 out, 1,000 a day	$61.880.21 cents a run	$2480.83 cents a run	4 times
Review a pull request25,000 in, 4,500 out, 50 a day	$53.443.6 cents a run	$21414 cents a run	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.

Start from a job

A short question and a few paragraphs back.

Read in 1 run

tokens

about 230 words

Read again from cache

Instructions or documents the model has read before cost far less the second time.

Written in 1 run, thinking included

tokens

about 380 words

Runs a day

A month of this job

Gemini 3.8 Flash$6.30
0.21 cents a run
Kimi K3$25.20
0.84 cents a run

Gemini 3.8 Flash saves $18.90 a month; Kimi K3 costs 4 times as much.

This job on every model

Why 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 Kimi K3?: Gemini 3.8 Flash is cheaper: $0.75 per million tokens read and $3.75 per million written, against $3 and $15 on Kimi K3. On a mix of 3 tokens read for each 1 written, Kimi K3 costs 4 times as much.
Which is better, Gemini 3.8 Flash or Kimi K3?: They cannot be told apart on the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks: Gemini 3.8 Flash scores 157 and Kimi K3 157, 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 3.8 Flash and Kimi K3?: 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 $666 on Kimi K3: Kimi K3 costs 4 times as much for this job.
What does an AI agent task cost on Gemini 3.8 Flash and Kimi K3?: 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 $2.20 on Kimi K3. At 10 tasks a day that is $165 and $659 a month.
Which has the larger context window, Gemini 3.8 Flash or Kimi K3?: 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 Kimi K3?: No. Our lesson "How AI writes", 1,700 words long, is about 2,200 tokens on Gemini 3.8 Flash and 2,055 on Kimi K3. Each maker cuts text its own way, and every extra token is paid for at the model's price.
Can I pay less on Gemini 3.8 Flash and Kimi K3 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