CalcSpark

Excel Column Converter

Instantly convert Excel column letters to numbers (A=1, Z=26, AA=27...)

Excel Date Converter

Convert Excel serial numbers to dates and dates to Excel serial numbers.

Percentage Calculator

Calculate percentages: X% of Y, what %, percentage change, apply a variation.

VAT Calculator

Convert pre-tax to total (with VAT) or total to pre-tax. Shows all three values instantly.

Column Number to Letter

Convert any Excel column number to its letter (1=A, 26=Z, 27=AA...). Reverse of the column converter.

Column Difference Calculator

Count how many columns are between two Excel column letters, with exclusive and inclusive counts.

Range Size Calculator

Enter a range like C5:F10 and instantly get the number of columns, rows, and total cells.

Column Offset Calculator

Apply a positive or negative offset to an Excel column letter and get the resulting column.

A1 ↔ R1C1 Converter

Convert Excel cell references between A1 and R1C1 notation. Useful for VBA authors and power users.