Formulas & Functions

Count business days between two dates in Excel with NETWORKDAYS and a holiday list, handle six-day weeks with NETWORKDAYS.INTL and find due dates with WORKDAY.

Calculate percentage change in Excel, even when the old value is negative or zero: the ABS fix, n/m for sign changes, and percent vs percentage points.

INDEX MATCH vs XLOOKUP, tested side by side: exact match, look left, not found, two criteria, last match and two-way lookups, plus which to use when.

Build a sales commission calculator in Excel: flat 10% commission, tier rates with XLOOKUP, and tiered (marginal) commission with SUMPRODUCT. Free template.

Why COUNTIFS returns 0 for two values in one column, and the SUM(COUNTIFS({…})) formula that counts either one, with AND criteria, cell lists and a check.

Use SUMIFS between two dates in Excel with start and end dates in cells, plus extra criteria, NOT, OR logic, EOMONTH month ranges and weekly totals.

Use the Excel gross margin percentage formula, calculate markup, find the overall weighted margin and set prices from a target margin. Free calculator.

Build an accounts receivable aging report in Excel with formulas for days past due, aging buckets, SUMIFS totals and an allowance estimate. Free template.

Learn how to use XLOOKUP in Excel with a real price-list example: return names and prices, handle missing SKUs, apply discount tiers and look left.

Calculate a weighted average in Excel with SUMPRODUCT by multiplying each value by its weight, then dividing by total weights.