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Working with pricing formulas

In Let's Book, you can enter formulas for discounts, commissions, and other calculations. they work very similar to how you'd use formulas / expressions in Excel. To ensure everything works correctly, it's important to use the proper notation. Below, we explain how to do this.

Using mathematical operators​

You can write formulas much like Excel. These operators are available:

  • Addition: +
  • Subtraction: -
  • Multiplication: *
  • Division: /

Example: Add 7.25% sales tax to $100: 100 * 1.0725

Keep order with parentheses​

When your formula has several steps, group them so the calculation reads the way you intend.

Example: Apply a $50 discount, then add 7.25% tax: (100 - 50) * 1.0725

Use functions for caps and floors​

Functions work like Excel and help you set simple guardrails.

min(value1, value2, ...)

Returns the smallest number.

Example: min(10, 5, 8) returns 5.

Use it to cap a value. For example, cap a discount at $50: min(subtotal * 0.2, 50)

max(value1, value2, ...)

Returns the largest number.

Example: max(10, 5, 8) returns 10

Use it to set a floor. For example, never charge less than $100: max(calculated_total, 100)

Use a period for decimals​

Enter decimals with a period. Commas cause errors.

  • Correct: 1.5
  • Incorrect: 1,5

Enter percentages as decimals​

Convert percentages to decimal numbers before you use them in a formula.

  • 7.25% becomes 0.0725
  • 15% becomes 0.15
  • 6% becomes 0.06

Quick examples you can copy​

  • $200 boat with 10% weekend surcharge: 200 * 1.10
  • 15% member discount capped at $75: min(total * 0.15, 75)
  • Commission of 12% after $25 cleaning fee: (total + 25) * 0.12

Common pitfalls​

  • Use periods, not commas, for decimals.
  • Enter percentages as decimals.
  • Use the right operators.
  • Add parentheses when you mix steps.

Your customers will thank you, and the math adds up every time.