A spreadsheet you can ask to do the work

Kantaja is a spreadsheet editor in your browser. Open an .xlsx, describe the change in your own words, and watch it happen in the grid: values, formulas, formatting. Save the file back out when you're done.

  • Opens and saves .xlsx
  • Edits happen in the grid, not in chat
  • Free plan, no card
q3-report.xlsx
D2fx
A
B
C
D
1
Product
Revenue
Cost
2
Aurora deck
12 400
9 800
3
Fjord kit
8 900
6 100
4
Lumo stand
6 250
4 300
5
Raita rail
4 780
3 950
6
Kide mount
3 420
2 210
Assistant

What it is

Ask in your own words

"Add a margin column and format it as a percentage." The assistant picks the ranges, writes the formula, and applies the formatting. You don't write the formula, but you can read it afterwards.

Works on .xlsx

Import the workbook you were sent and export one that opens in Excel, with formulas, number formats and multiple sheets intact.

A full editor underneath

Every edit lands in a normal grid you can keep working in: type in cells, write your own formulas, sort, format. The assistant is one way to work in it, not the only way.

One run, start to finish

01

Import your workbook

Upload an .xlsx, or start from an empty sheet. It runs in the browser, so there is nothing to install.

02

Describe the change

"Fill the unit price column from the price list PDF." Attach the documents the answers come from, and the assistant searches them before it writes.

03

Check it and export

Each action shows the range it touched, so you can spot-check the cells. Fix anything by hand, revert the run, or export the .xlsx.

Knowledge base

Attach the documents the answers come from

Prices in a supplier PDF, terms in a contract, notes in a text file. Kantaja indexes what you attach and searches it when a request depends on it, then writes the values it found into the cells. Each answer comes with the passage it came from, so a wrong value is traceable to a source rather than a guess.

  • PDF, Word and plain text, up to 20 files per workbook
  • Quotes the passage it used, so you can check the source
  • Available in chat and inside =AI() formulas
Knowledge base
price-list-2026.pdf1.2 MBReady
supplier-contract.docx340 KBReady
shipping-notes.txt18 KBIndexing
Fill the unit price column from the price list
search_files "unit price"
"Alu bracket 40 mm, unit price €4.20"

price-list-2026.pdf

set_values C2:C14

The =AI() formula

AI in a cell, like any formula

Give it a prompt and the cells to look at, then fill it down. One value per row: categorize expenses, translate a column, pull a number out of a messy text field. A result holds until its inputs change or you refresh it, so editing elsewhere in the sheet does not recalculate and re-bill the column.

  • Fill down a column like any other formula
  • A result holds until its inputs change or you refresh it
  • Can search your attached documents for the answer
B2fx=AI("Categorize this expense", A2)
A
B
1
Expense
Category
2
Taxi from the airport
Travel
3
Figma seats, May
Software
4
Team lunch, offsite
Meals
5
Print run, spring flyers
Marketing
6
AWS invoice, April
Cloud

It will get things wrong sometimes

It's a language model, so it can misread a request or a column. Kantaja is built so that a mistake is easy to see and easy to undo: three actions can write to your sheet, and each one is logged with the exact range it touched while it runs.

Revert a run

A run is one entry in the log. Reverting it puts the cells it wrote back the way they were, without touching edits you made yourself.

Can write to your sheet

set_valuesWrites values into the cells it names.
apply_formulaWrites a formula into a range.
format_rangeChanges number formats and styling.

Read-only

read_rangeReads cells before deciding what to do.
search_filesSearches the documents you attached.

Questions, answered

What happens to my files and my data?

Workbooks and attached documents are stored in your account so you can come back to them, and you can delete them at any time. Requests are sent to the AI provider to produce a result. See the privacy policy for the full detail.

How faithful is the .xlsx round trip?

Values, formulas, number formats and multiple sheets survive import and export. Very Excel-specific features such as pivot tables, macros and charts are not supported, so check a copy before you replace an original.

What if it does the wrong thing?

Each action shows the range it touched while it runs, so you can check the cells straight away. You can edit anything by hand, or revert a whole run in one click.

Do I need Excel installed?

No. Kantaja is a spreadsheet editor that runs in the browser. You only need Excel for whatever you do with the file afterwards.

What documents can it read?

PDF, Word and plain text, up to 20 files per workbook. The assistant and =AI() search them and quote the passages they used, so you can check where a value came from.

What is =AI()?

A worksheet function: give it a prompt and the cells to look at, and it returns one value per cell. Fill it down like any formula. A result stays put until its inputs change or you refresh it, so it is not recalculated and re-billed on every edit.

What happens when the daily credits run out?

AI features pause until the next day. The editor keeps working, so you can carry on by hand or upgrade for a larger daily budget.

Can my team work in the same workbooks?

Yes, on the Business plan. Create an organization, invite members, and everyone works in the same workbooks with AI usage tracked at the organization level.

Try it on a file you already have

Start freeFree plan: 4 AI credits a day, 5 workbooks, no card.