Which is cheaper, Gemini 3.8 Flash or GPT-6.1 Sol?

Gemini 3.8 Flash is cheaper: $0.75 per million tokens read and $3.75 per million written, against $2 and $10 on GPT-6.1 Sol. On a mix of 3 tokens read for each 1 written, GPT-6.1 Sol costs 2.7 times as much.

Which is better, Gemini 3.8 Flash or GPT-6.1 Sol?

On the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks, GPT-6.1 Sol scores 166 and Gemini 3.8 Flash 157, above the top of the range of doubt around Gemini 3.8 Flash's score (GPT-5 is 150). One score is an average; test both on your own work before you switch.

What does a support bot cost a month on Gemini 3.8 Flash and GPT-6.1 Sol?

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 $432 on GPT-6.1 Sol: GPT-6.1 Sol costs 2.6 times as much for this job.

What does an AI agent task cost on Gemini 3.8 Flash and GPT-6.1 Sol?

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 $1.21 on GPT-6.1 Sol. At 10 tasks a day that is $165 and $364 a month.

Which has the larger context window, Gemini 3.8 Flash or GPT-6.1 Sol?

GPT-6.1 Sol, with 1.05M tokens against 1.05M on Gemini 3.8 Flash. The window holds your instructions, the files you attach, the conversation so far and the answer, all at once.

Does the same text take the same number of tokens on Gemini 3.8 Flash and GPT-6.1 Sol?

No. Our lesson "How AI writes", 1,700 words long, is about 2,200 tokens on Gemini 3.8 Flash and about 2,100 on GPT-6.1 Sol. 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 GPT-6.1 Sol for work that can wait?

On GPT-6.1 Sol only: with a batch, where you collect the answers later, it costs $1 per million tokens read and $5 written. Google's price page lists no batch price for Gemini 3.8 Flash.

Gemini 3.8 Flash vs GPT-6.1 Sol

Gemini 3.8 Flash is the cheaper of the 2: for the same tokens, 3 read for each 1 written, GPT-6.1 Sol costs 2.7 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; GPT-6.1 Sol costs 2.7 times as much
Cheaper to read: Gemini 3.8 Flash, $0.75 against $2
Cheaper to write: Gemini 3.8 Flash, $3.75 against $10
Scores higher: GPT-6.1 Sol, 166 against 157
Larger window: GPT-6.1 Sol, 1.05M against 1.05M tokens

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	GPT-6.1 SolOpenAI
InputTokens the model reads	$0.75	$2
Cached inputRead again from the cache	$0.075	$0.10
Cache writePutting text in the cache	Not listed	$2.50
OutputTokens it writes, thinking included	$3.75	$10
Blend 3:13 tokens read for each 1 written	$1.50	$4
Batch inputAnswers collected later	Not listed	$1
Batch output	Not listed	$5
Long prompt inputAbove 272K on GPT-6.1 Sol	$0.75	$4
Long prompt outputThe standard price where there is no long-prompt price	$3.75	$15
Context windowTokens it holds at once	1.05M	1.05M
Capability scoreEpoch Capabilities Index; GPT-5 is 150	157	166
Longest answerTokens it writes in 1 reply	66K	128K

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.
GPT-6.1 Sol
about 2,100 tokens
Sent once: 0.41 cents at $2 per million
GPT-5.6 is counted with o200k_base, the tokenizer OpenAI publishes for it, so its count is exact. OpenAI has not published the tokenizer of GPT-6, so its count is the same o200k_base figure, marked as about.

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 GPT-6.1 Sol for the same words, so its bill for the same work can be up to that much higher.

Job	Gemini 3.8 Flash	GPT-6.1 Sol	Difference
A chat question300 in, 500 out, 100 a day	$6.300.21 cents a run	$16.800.56 cents a run	2.7 times
A hard question, with thinking300 in, 1,400 out, 100 a day	$16.430.55 cents a run	$43.801.5 cents a run	2.7 times
A long report, summarised60,000 in, 2,000 out, 20 a day	$31.505.3 cents a run	$84.0014 cents a run	2.7 times
A 40-turn agent task2,800,000 in, 40,000 out, 10 a day	$16555 cents a run	$364$1.21 a run	2.2 times
A support bot's reply4,000 in, 300 out, 2,000 a day	$1660.28 cents a run	$4320.72 cents a run	2.6 times
Sort a message into a category250 in, 5 out, 50,000 a day	$3090.021 cents a run	$8250.055 cents a run	2.7 times
Read an invoice into fields1,500 in, 250 out, 1,000 a day	$61.880.21 cents a run	$1650.55 cents a run	2.7 times
Review a pull request25,000 in, 4,500 out, 50 a day	$53.443.6 cents a run	$1439.5 cents a run	2.7 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
GPT-6.1 Sol$16.80
0.56 cents a run

Gemini 3.8 Flash saves $10.50 a month; GPT-6.1 Sol costs 2.7 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 GPT-6.1 Sol?: Gemini 3.8 Flash is cheaper: $0.75 per million tokens read and $3.75 per million written, against $2 and $10 on GPT-6.1 Sol. On a mix of 3 tokens read for each 1 written, GPT-6.1 Sol costs 2.7 times as much.
Which is better, Gemini 3.8 Flash or GPT-6.1 Sol?: On the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks, GPT-6.1 Sol scores 166 and Gemini 3.8 Flash 157, above the top of the range of doubt around Gemini 3.8 Flash's score (GPT-5 is 150). One score is an average; test both on your own work before you switch.
What does a support bot cost a month on Gemini 3.8 Flash and GPT-6.1 Sol?: 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 $432 on GPT-6.1 Sol: GPT-6.1 Sol costs 2.6 times as much for this job.
What does an AI agent task cost on Gemini 3.8 Flash and GPT-6.1 Sol?: 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 $1.21 on GPT-6.1 Sol. At 10 tasks a day that is $165 and $364 a month.
Which has the larger context window, Gemini 3.8 Flash or GPT-6.1 Sol?: GPT-6.1 Sol, with 1.05M tokens against 1.05M on Gemini 3.8 Flash. The window holds your instructions, the files you attach, the conversation so far and the answer, all at once.
Does the same text take the same number of tokens on Gemini 3.8 Flash and GPT-6.1 Sol?: No. Our lesson "How AI writes", 1,700 words long, is about 2,200 tokens on Gemini 3.8 Flash and about 2,100 on GPT-6.1 Sol. 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 GPT-6.1 Sol for work that can wait?: On GPT-6.1 Sol only: with a batch, where you collect the answers later, it costs $1 per million tokens read and $5 written. Google's price page lists no batch price for Gemini 3.8 Flash.

Sources