Expressions & computed fields

An Expression is a formula written in terms of other fields' names, wrapped in curly braces — {fieldName} — that Craftor evaluates live in the browser as the visitor fills in the form. Two things use them: the dedicated Computed/Expression field type (shows the result as its own field) and the Range Slider's optional Min/Max Value Expression settings (drives a slider's bounds off another field instead of a fixed number).

Adding a computed field

1. 1Add a field and set its type to Computed / Expression.
2. 2In the Expression setting, write a formula referencing other fields by name, e.g. {quantity} * {price}.
3. 3Set Display As to control formatting: Plain Number, Decimal, Currency (pick the currency), Percent, or Date.

{quantity} * {price}
({subtotal} - {discount}) * 1.1   // apply 10% tax after a discount
{hours_worked} > 40 ? {hours_worked} - 40 : 0   // overtime hours
iif({country} = 'US', {price}, {price} * 1.2)   // conditional formula

Formula reference

• Reference a field: {fieldName} — the same auto-generated name used everywhere else (conditional logic, merge tags, workflow steps).
• Arithmetic: + - * / and parentheses for grouping, following normal order of operations.
• Comparisons: = != > >= < <=, and and / or to combine them.
• Conditional: condition ? valueIfTrue : valueIfFalse, or the equivalent iif(condition, valueIfTrue, valueIfFalse).
• String matching: contains / notcontains, e.g. {email} contains '@company.com'.

Driving a slider's range from another field

On a Range Slider field, Min Value Expression and Max Value Expression (under its slider settings) take the same formula syntax and override the plain Min Value/Max Value settings whenever they're non-empty — e.g. set Max Value Expression to {budget} so a "how much to allocate to this category" slider can never exceed what the visitor entered as their total budget earlier in the form.