No-code calculations and business rules

A no-code calculation turns inputs into a result. A business rule decides what that result means or what happens next. Define both in plain language before building. Specify inputs, units, missing-value treatment, rounding point and the person responsible for each important result, then check the rule against examples with known answers.

Start with the decision

Suppose an internal app estimates a service charge as hours × hourly rate + fixed fee. A separate rule flags estimates above an agreed threshold for review. Decide whether that comparison uses the unrounded result or a rounded amount; otherwise the displayed amount and review decision may appear to disagree.

Record who supplies each input, when the result updates and who can approve an exception.

Choose where the result belongs

Check where a calculated value is evaluated and stored in your chosen platform, and whether it updates when source data changes.

Confirm how the platform handles default values, overrides and formula fields across records before relying on a result elsewhere. Verify the behaviour in the actual app.

Separate the number from its presentation

Keep a result numeric while other calculations or comparisons need it. A currency symbol or displayed decimal places do not, by themselves, define when the business rule rounds. Decide separately whether a rounded number should drive a decision.

Write down the precision and point of rounding, including whether it applies to each item or a total. Function names are not enough: Power Fx Round accepts a decimal-places argument.

Consider local format interpretation

Power Fx can format dates and times with predefined formats that adjust to a user's language and region. With a custom format, the language placeholder affects how other placeholders are interpreted, including whether a period is a decimal separator or a thousands separator.

Define missing and exceptional inputs

A blank amount is not necessarily zero. If hours are unknown, decide whether the estimate remains blank, shows a pending state or stops the workflow. Power Fx distinguishes blank from numeric zero and documents Coalesce for handling blank values or empty strings; choosing a fallback is still a business decision.

Consider zero quantities, negative values, changed rates and division by zero where relevant. State which inputs are valid and which require correction or a person's judgement.

No-code platform functions for handling values

Distinguish missing values from empty tables

In Power Fx, blank represents no value or an unknown value, and can represent a NULL returned by a data source. An empty string is text with no characters, although some controls and data sources use it to mean no value. Decide whether the business rule treats these states alike.

IsBlank tests for a blank value or an empty string. IsEmpty is for tables that contain no records; an empty table is not the same as a blank scalar value.

Power Fx: `IsBlank` vs `IsEmpty` – understanding the difference

Check and maintain the rule

Before configuring the field, prepare a few inputs with expected outputs: an ordinary case, a threshold boundary, zero, blank and an invalid case. In the configured app, compare the calculated value, what users see and any downstream decision.

Keep the rule's purpose, inputs, calculation order, rounding policy and examples with its configuration. When a rate or threshold changes, record its effective date and decide whether earlier records retain their results or are recalculated.