Formula fields: calculate values from your contract data automatically

What's in it for you

Contract values get converted constantly: a monthly rate becomes an annual total, an indexation percentage becomes a price adjustment, an end date and a notice period become a “last possible termination date”. Until now that meant calculating by hand, maintaining values twice, and making mistakes. With formula fields:

Fewer arithmetic errors. The formula reads your contract data live. Change the monthly rate and the annual total changes with it.
Consistency across every contract. The same calculation logic applies to every contract in the category — no copy-paste, no per-contract exceptions.
Less manual upkeep. Anything that can be calculated no longer needs to be typed. Users save time and the data stays current.
Usable in views and reports. Formula fields behave like ordinary number or date fields: you can filter, sort and group by them and use them in reports.

How it works

Step 1: Create a new field with the “formula” field type

Open the contract field builder (Settings → Field builder → Contract field builder). On the right, under your fields, click the + icon.

As the field type, choose formula.

A note tells you that formula fields do not support AI prompts. In other words: a formula field calculates — it cannot be filled by an AI prompt. The AI can still deliver the input fields that the formula then works with.

Step 2: Build the formula by clicking fields together

The editor is field-based — there is no free-text input, you assemble the formula click by click:

Existing fields from the category — each shown with its field type (for example “net rent → currency”, “contract end → date”). Number, currency, date and interval fields can be used.
Your own numbers — just type the number and the dropdown offers to use it as a value. Typical constants: × 12 for a year, ÷ 100 for a percentage, × 1.19 for VAT.
Operators — addition +, subtraction −, multiplication ×, division ÷.

The dropdown switches automatically between fields and operators — you can only pick what makes sense at that position. After a × on a currency field, for instance, the picker automatically narrows to number and currency fields and hides dates.

Step 3: Check the status

The top right of the editor shows the current state of your formula: a draft state when nothing has been entered yet, an invalid state when the formula is incomplete (a field without an operator, for example), and a valid state once it can be calculated.

Step 4: Test the formula against real contracts

As soon as the formula is valid, a contract selector appears. Pick an existing contract from your portfolio — ContractHero drops the actual values into the formula and shows you the result immediately, for example “net rent (€1,500) × 12 = 18,000”.

If an input value is missing in the contract you picked, you'll see a “not available” placeholder and a clear warning naming the field that has no value in that contract — so you know straight away which data still needs maintaining.

Typical use cases

Annual total from a monthly rate. “Net rent × 12” — €2,000 × 12 = €24,000 per year. A classic for rental, leasing and SaaS contracts.
Price adjustment from an indexation clause. “Net amount × adjustment %” — €24,000 × 0.03 = €720. Ideal for making the absolute increase visible.
Last possible termination date. “Contract end − notice period” — end 31 Dec 2026 minus 3 months = 30 Sep 2026. For newly created organisations this field comes preconfigured as a standard formula and appears in the term section.
Total contract volume. “Monthly rate × term in months” — an instant view of a contract's total commitment.
Net to gross and back. “Net × 1.19” or “Gross ÷ 1.19” — whichever value your reports need.
Remaining balance. “Invoice total − down payment” — the outstanding amount carried automatically.

Common questions

Which field types can I use in a formula?
Number fields, currency fields, date fields and interval fields. Text fields, lists and other types (checkbox, link, duration) cannot be used in formulas. The dropdown shows you exactly which fields are available in your category.

Can I put my own numbers into the formula?
Yes. Type the number and pick the option to use it as a value. Typical constants: × 12 (a year), ÷ 100 (a percentage), × 1.19 (VAT).

Why can't I add an AI prompt to a formula field?
Formula fields calculate deterministically — they are not filled by the AI. The AI only supplies the input values (net rent, for example) and the formula works with those.

How do I know my formula works?
The editor gives you a live test: pick a contract from your portfolio and you see the calculated result immediately, before you save the field.

What happens if an input field is empty in a contract?
The formula cannot calculate. In the live test you get a “not available” placeholder and a warning naming the field without a value. Once that value is filled in, the result updates automatically.

Can formula fields be used in views and reports?
Yes. A formula field behaves like an ordinary number or date field — you can display it in contract views, filter, sort and use it in reports.

Can I use a formula field as the input for another formula?
Yes. Formula fields appear in the field picker like any other field, so you can build multi-step calculations — first an annual total, then that total × the number of years.

Can I reuse formulas across categories?
Formula fields belong to a category. If you need the same calculation in another category, create the formula field there too — the same logic as with normal fields.

Does the preconfigured “last possible termination date” apply to existing organisations?
The automatic preconfiguration applies to newly created organisations. Existing organisations can create the field manually with the same formula (contract end − notice period) for the same result.

Does this cost extra?
No. Formula fields are available to all customers on all plans — no add-on required.

Good to know

Consistent basics pay off. A formula is only as good as its inputs. Maintain “net rent” consistently and you get a clean annual total for free.
Use telling field names. “Annual total (calculated)” or “Termination date (auto)” makes clear that the value is computed, so users don't try to type into it.
AI and formulas complement each other. Formula fields don't take AI prompts themselves, but if the AI contract analysis extracts the base values automatically, the formulas run on their own from there.
Works retroactively. Create a new formula field and existing contracts fill in automatically — as long as the input fields are maintained. No re-analysis needed.
Excel export includes the result. The export carries the calculated value per contract — the result, not the formula.
Test first, save second. Run the contract test against at least two different contracts before you put the field into production — that catches edge cases early.

Updated on: 09/04/2026

Was this article helpful?

Thank you!