Calculations

What are Calculated Fields?

Calculated fields display computed values based on other form fields. They update in real time as users enter data, providing instant feedback for quotes, totals, taxes, and complex formulas.

Perfect for order forms, quote calculators, and any form that needs mathematical operations.

Adding a Calculated Field

1. In the form editor, add a Calculated Field block
2. Write your formula in the Calculation panel
3. Reference other fields by their names
4. Test in preview mode

The field appears as a read-only input that updates automatically.

Writing Formulas

Formulas use standard mathematical operators and function calls:

Basic Operators

quantity * price
(subtotal + tax) - discount
hourly_rate * hours_worked

Field References

Reference other fields by their exact field names:

base_price * 1.2        // 20% markup
length * width * height  // Volume calculation

Field names are case-sensitive and cannot contain spaces. Use underscores or camelCase.

Mathematical Functions

Basic Math

abs(value)          // Absolute value
round(value, 2)     // Round to 2 decimal places
ceil(value)         // Round up
floor(value)        // Round down
pow(base, exponent) // Power
sqrt(value)         // Square root

Conditional Logic

if(condition, true_value, false_value)

if(quantity > 10, price * 0.9, price)  // 10% bulk discount

Complex Example

// Shipping calculator
if(weight <= 2, 5.99, 
   if(weight <= 5, 9.99, 
      weight * 2.50))

Common Formulas

Order Total with Tax

(quantity * unit_price) * (1 + tax_rate / 100)

Area Calculation

length * width

Volume Calculation

length * width * height

Percentage Discount

original_price * (1 - discount_percentage / 100)

Compound Interest

principal * pow(1 + annual_rate / 100, years)

BMI Calculator

weight / pow(height / 100, 2)

Formatting Results

Control how calculated values display:

Currency Formatting

Format: Currency
Symbol: $
Decimals: 2
Result: $42.99

Percentage

Format: Percentage  
Decimals: 1
Result: 15.5%

Number with Units

Format: Number
Suffix: " sq ft"
Result: 250 sq ft

Custom Formatting

Format: Custom
Pattern: "Total: {value} items"
Result: Total: 42 items

Real-Time Updates

Calculated fields update instantly when referenced fields change:

• Text inputs — on every keystroke
• Dropdowns — when selection changes
• Checkboxes — when checked/unchecked
• Radio buttons — when selection changes

No submit button required. Users see results immediately.

Conditional Calculations

Use if-then logic for complex scenarios:

Tiered Pricing

if(quantity >= 100, unit_price * 0.8,
   if(quantity >= 50, unit_price * 0.9, 
      unit_price))

Membership Discounts

if(membership_level == "Gold", total * 0.85,
   if(membership_level == "Silver", total * 0.9, 
      total))

Shipping Zones

if(country == "US", 5.99,
   if(country == "Canada", 12.99, 
      25.99))

Multiple Calculations

Forms can have multiple calculated fields that reference each other:

// Field 1: Subtotal
quantity * unit_price

// Field 2: Tax
subtotal * 0.08

// Field 3: Total
subtotal + tax

Dependencies update in order, so "Total" automatically includes the latest tax calculation.

Error Handling

Division by Zero

if(denominator == 0, 0, numerator / denominator)

Invalid Numbers

Non-numeric inputs are treated as zero in calculations.

Missing Fields

If a referenced field doesn't exist, it's treated as zero.

Common Use Cases

Quote Calculators

Calculate project costs based on requirements:

base_cost + (hours * hourly_rate) + material_costs

Order Forms

Show running totals as customers shop:

sum_of_line_items + shipping + tax

Loan Calculators

Calculate monthly payments:

principal * (rate * pow(1 + rate, months)) / (pow(1 + rate, months) - 1)

Unit Converters

Convert between measurement systems:

feet * 0.3048  // Feet to meters

Best Practices

Clear Field Names

Use descriptive names that make formulas readable:

// Good
monthly_salary * 12

// Bad  
field_1 * field_2

Test Edge Cases

Consider what happens with:

• Zero values
• Negative numbers
• Very large numbers
• Empty fields

Provide Context

Use help text to explain what's being calculated:

"Estimated monthly payment based on current rates"

Format Appropriately

Currency for money, percentages for rates, plain numbers for quantities.

Troubleshooting

Calculation Not Updating

• Check field name spelling (case-sensitive)
• Ensure referenced fields exist
• Verify formula syntax

Wrong Results

• Test with simple values first
• Check operator precedence (use parentheses)
• Verify field types (text vs number)

Performance Issues

• Complex formulas can slow form interaction
• Simplify calculations where possible
• Consider server-side calculations for heavy processing

NaN Results

"Not a Number" usually means:

• Invalid formula syntax
• Division by zero without protection
• Non-numeric input in calculation

Use browser developer tools to debug formula errors.