Skip to main content
Mobius
Intermediate

What is model training

Also known as: AI training, training

Definition

Model training is how an AI model learns: it sees many examples, checks its guesses against the right answers and adjusts itself until the errors shrink.

Why it matters

You will almost certainly not train a large model: the cost is far beyond a small business, which is why businesses use models someone else trained.

Common mistakes

Calling the upload of files to a chat tool training, and expecting the model itself to have learned them.

Worked exampleIllustration

A small model learns to sort a fictional pilates studio's WhatsApp messages

A small model learns to sort a fictional neighbourhood pilates studio's WhatsApp messages into booking, cancellation and question, from 20 messages the owner labelled. Every number is invented for this example.

  1. Guess

    In the first round it sorts the 20 labelled messages and gets 8 right.

    8 ÷ 20 = 40%
  2. Compare

    Each guess is compared with the owner's label.

  3. Adjust

    It adjusts itself and repeats. After several rounds it gets 17 of the 20 right.

    17 ÷ 20 = 85%
  4. Test

    On 10 new messages it never saw, it gets 7 right.

    7 ÷ 10 = 70%

The score on new messages is the one that counts. The big chat model you use was trained the same way, only by its vendor, on far more text.

Illustration

Train one round at a time

Round 6: 17 of 20 right

  • Booking
  • Question
  • Cancel
  • Booking
  • Question
  • Booking
  • Cancel
  • Question
  • Booking
  • Cancel
  • Question
  • Booking
  • Question
  • Cancel
  • Booking
  • Question
  • Bookingshould be Cancel
  • Booking
  • Cancelshould be Question
  • Bookingshould be Cancel

White line: round 1, 8 of 20

After the last round: 17 of 20 right, up from 8 in round 1. The score that counts comes next, on messages it never saw.

Training is guess, compare with the owner’s label, adjust, repeat. Each round the model sorts the same 20 messages again and gets more of them right.

Trained once, used every time

Training happens once, by the vendor, before anyone asks a question. Inference runs on every question, every month, for as long as the model is used.⁨Training⁩⁨once, by⁩⁨the vendor⁩⁨Model⁩⁨Inference⁩⁨every question,⁩⁨every month⁩
Training happens once, by the vendor, before anyone asks a question. Inference runs on every question, every month, for as long as the model is used.

Definition

Model training is how an AI model learns. It is shown a large number of examples, makes a guess for each, compares the guess with the right answer and adjusts its internal settings to be a little less wrong, round after round, until the errors stop shrinking. Large language models are trained first on vast amounts of text, learning to predict the next piece of it. The chat tool you use was trained this way by its vendor, on text up to a date, so it knows nothing after that date and nothing about your business unless you give it the information. Uploading files to a chat tool is not training: the tool searches the files, and the model stays the same.

Why it matters

Your part is different. Give the model your facts when it answers, and know whether your own conversations may be used to train the vendor's next version, which is a setting of your plan.

Directly related: Inference, AI Model, Fine-tuning.

Improvement tips

  • Check your plan's setting on whether your conversations may be used to train future models, and choose on purpose.
  • Give the model your business facts in its instructions or documents, since its training did not include them.
  • Judge any trained model on new examples it never saw, not on the ones it learned from.
  • For anything recent, give the model the source or use a tool that searches, because its knowledge stops at a date.

Common mistakes

  • Judging a model by its score on the examples it was trained on.
  • Assuming a trained model knows recent events or your current hours.
  • Leaving the plan's training setting at its default without knowing what the default is.

Related terms

Quick check

A model sorts 17 of 20 training messages correctly and 7 of 10 new messages. Which score tells you how it will do next week?

Choose an answer

Frequently asked questions

What is model training in simple words?
The stage where an AI model learns. It sees many examples, guesses, checks each guess against the right answer and adjusts itself, round after round, until it makes fewer mistakes.
What is the difference between training and inference?
Training is learning, done once or now and then, usually by the vendor. Inference is using the trained model to answer, and it happens every time someone asks.
Do I need to train my own model?
Almost never. Training a large model costs far beyond a small business, which is why businesses use models someone else trained. What you need is to give a ready model your facts, through its instructions or your documents.
Is uploading my files to a chat tool training?
No. The tool searches your files for relevant passages when you ask, and the model itself does not change. Anthropic's help page on Projects, for example, says Claude uses a project knowledge search tool to retrieve relevant information from your uploaded documents. That is RAG, not training.
Why doesn't the model know about something that happened last month?
Because its training text stops at a date, its knowledge cutoff. After that date the model knows nothing unless the tool searches the web or reads a source you give it. Anthropic's documentation, for example, lists a reliable knowledge cutoff for each model.
Why doesn't the model know our hours and rules?
Because they were never in its training text. Put them in its instructions or in a document it reads with each question, and update that document when they change.
Are my conversations used to train the AI?
It depends on the plan and its settings. Anthropic, for example, uses chats from its consumer plans to improve its models only if the user allows it, and by default does not use inputs from its commercial products for training. Other vendors set this differently, so check your plan's setting.
Is it risky to let a vendor train on our data?
It can be, if the data includes customer details. Check the vendor's terms on sharing and on using your data for training, and keep personal details out of what you send. Israel's Privacy Protection Law, 1981, as amended by Amendment 13, in force since 14 August 2025, governs collecting, keeping and using personal details, including details you paste into or upload to an AI tool. Educational material, not legal or tax advice. Check your own case with a lawyer or an accountant.
Can I train a small model myself?
With someone technical, yes, for a narrow task such as sorting messages into types, from examples you label. Test it on new examples it never saw before you rely on it.
Why did the model score well in testing and badly in real use?
Often because it was tested on the same examples it learned from. A fair test uses new examples. In the worked example on this page the model got 85% on its training messages and 70% on new ones.
Does training make a model always right?
No. Training lowers its errors on the kind of examples it saw. It still makes mistakes, more of them on cases unlike its examples, so its outputs need checking.
What is the difference between training and fine-tuning?
Training builds the model from a vast amount of data. Fine-tuning is extra training of a ready model on a small set of your own examples, to teach it a style, a format or a narrow task.

Sources: Anthropic, "Models overview", Claude documentation, the rows "Reliable knowledge cutoff" and "Training data cutoff" (platform.claude.com/docs/en/about-claude/models/overview), read 2026-09-25, Anthropic Privacy Center, "Is my data used for model training?", consumer and commercial articles (privacy.claude.com), read 2026-09-25, Anthropic Help Center, "Retrieval augmented generation (RAG) for projects" (support.claude.com/en/articles/11473015), read 2026-09-25, Privacy Protection Authority, Amendment 13 questions and answers (gov.il/he/pages/tikun13_qa), read 2026-08-31

Last reviewed: 2026-09-25

I have worked with

What Clients Say

From different fields, at different stages of business

Dan Manto

Eclipse Capital

Real Estate Investment and Finance, USA

Arty McLabin

GameReady

Game Development Education and Outsourcing, International

Anna, Beautician

Anna

Beautician

After I finished a cosmetology course at a leading company, I was confused. I didn't know how to open a business, what to sell from home, or how to bring in clients. Since I reached out to Mobius, everything has changed. We built an organized plan with clear steps and no unnecessary risks. Today I see results, and I'm growing and developing every month.

Mark, Massage therapist, Gan Yavne

Mark

Massage therapist, Gan Yavne

When I finished a massage course, I imagined a different world. I found out it's a hard field, and financial stability isn't easy to find. When I came to Mobius, something changed. We started an organized process and built a business plan. Without Mobius? I probably would have given up. Today I believe in myself and in my own path.

Wondering where AI actually fits your business?

Alex helps Israeli businesses use AI and data where it pays off, and skip it where it does not. The first call is free.

+972 055-248-6151. Better on WhatsApp: I am in meetings most of the day and answer as soon as I am free.