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GPT-3.5 Turbo (0125) vs GPT-6.1 Sol

GPT-6.1 Sol is one of OpenAI's newest models and GPT-3.5 Turbo (0125) an earlier one, so this is also what moving up costs or saves. GPT-3.5 Turbo (0125) is the cheaper of the 2: for the same tokens, 3 read for each 1 written, GPT-6.1 Sol costs 5.3 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
GPT-3.5 Turbo (0125) is cheaper; GPT-6.1 Sol costs 5.3 times as much
Cheaper to read
GPT-3.5 Turbo (0125), $0.50 against $2
Cheaper to write
GPT-3.5 Turbo (0125), $1.50 against $10
Scores higher
Not known, GPT-3.5 Turbo (0125) has no independent score yet
Larger window
Not listed for GPT-3.5 Turbo (0125)

Price per million tokens, side by side

In US dollars, as each maker prints them. The better figure in each row is green.

GPT-3.5 Turbo (0125)OpenAI · earlier modelGPT-6.1 SolOpenAI
InputTokens the model reads$0.50$2
Cached inputRead again from the cacheNot listed$0.10
Cache writePutting text in the cacheNot listed$2.50
OutputTokens it writes, thinking included$1.50$10
Blend 3:13 tokens read for each 1 written$0.75$4
Batch inputAnswers collected later$0.25$1
Batch output$0.75$5
Long prompt inputAbove 272K on GPT-6.1 Sol$0.50$4
Long prompt outputThe standard price where there is no long-prompt price$1.50$15
Context windowTokens it holds at onceNot listed1.05M
Capability scoreEpoch Capabilities Index; GPT-5 is 150Not listed166
Longest answerTokens it writes in 1 replyNot listed128K

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.

JobGPT-3.5 Turbo (0125)GPT-6.1 SolDifference
A chat question300 in, 500 out, 100 a day$2.700.09 cents a run$16.800.56 cents a run6.2 times
A hard question, with thinking300 in, 1,400 out, 100 a day$6.750.23 cents a run$43.801.5 cents a run6.5 times
A long report, summarised60,000 in, 2,000 out, 20 a day$19.803.3 cents a run$84.0014 cents a run4.2 times
A 40-turn agent task2,800,000 in, 40,000 out, 10 a day$438$1.46 a run$364$1.21 a run1.2 times
A support bot's reply4,000 in, 300 out, 2,000 a day$1470.24 cents a run$4320.72 cents a run2.9 times
Sort a message into a category250 in, 5 out, 50,000 a day$1990.013 cents a run$8250.055 cents a run4.2 times
Read an invoice into fields1,500 in, 250 out, 1,000 a day$33.750.11 cents a run$1650.55 cents a run4.9 times
Review a pull request25,000 in, 4,500 out, 50 a day$28.881.9 cents a run$1439.5 cents a run4.9 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.

tokens

about 230 words

0%

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

tokens

about 380 words

A month of this job

  • GPT-3.5 Turbo (0125)$2.70

    0.09 cents a run

  • GPT-6.1 Sol$16.80

    0.56 cents a run

GPT-3.5 Turbo (0125) saves $14.10 a month; GPT-6.1 Sol costs 6.2 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, GPT-3.5 Turbo (0125) or GPT-6.1 Sol?
GPT-3.5 Turbo (0125) is cheaper: $0.50 per million tokens read and $1.50 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 5.3 times as much.
Which is better, GPT-3.5 Turbo (0125) or GPT-6.1 Sol?
GPT-6.1 Sol scores 166 on the Epoch Capabilities Index, an independent score from Epoch AI that combines over 50 benchmarks (GPT-5 is 150). GPT-3.5 Turbo (0125) 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 GPT-3.5 Turbo (0125) 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 $147 a month on GPT-3.5 Turbo (0125) and $432 on GPT-6.1 Sol: GPT-6.1 Sol costs 2.9 times as much for this job.
What does an AI agent task cost on GPT-3.5 Turbo (0125) 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 $1.46 on GPT-3.5 Turbo (0125) and $1.21 on GPT-6.1 Sol. At 10 tasks a day that is $438 and $364 a month.
Does the same text take the same number of tokens on GPT-3.5 Turbo (0125) and GPT-6.1 Sol?
Yes, both are counted the same way: our lesson "How AI writes", 1,700 words long, is about 2,100 tokens on each.
Is it cheaper to move from GPT-3.5 Turbo (0125) to GPT-6.1 Sol?
No, it costs more per token: GPT-6.1 Sol charges $2 per million tokens read and $10 written, against $0.50 and $1.50 on GPT-3.5 Turbo (0125), 5.3 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 GPT-3.5 Turbo (0125) and GPT-6.1 Sol for work that can wait?
Yes, on both. With a batch, where you collect the answers later instead of at once, GPT-3.5 Turbo (0125) costs $0.25 per million tokens read and $0.75 written, and GPT-6.1 Sol $1 and $5.

Sources

Where each fact comes from

  1. 1OpenAI: API prices
  2. 2How OpenAI models count tokens, source 1
  3. 3How OpenAI models count tokens, source 2
  4. 4Epoch Capabilities Index, by Epoch AI (CC BY 4.0)