Percentage Decrease Calculator

Percentage Decrease in Excel

Excel and Google Sheets both love explicit numerators and denominators. Avoid hidden rounding in the headline cell.

Percentage Decrease Calculator

Quick answer

Use ((A1−B1)/A1) when A1 is baseline and B1 is new; format the result as a percent if you like.

((baseline cell − new cell) / baseline cell)

Introduction

After you trust a row in Excel, you can spot-check it with the Percentage Decrease Calculator.

Main content

What is it?

Spreadsheets make it easy to repeat the same decrease calculation for many SKUs, weeks, or classrooms. The definition does not change; only the scale does.

Formula in sheets

=(A1-B1)/A1

Wrap with parentheses if you combine with other operations, and keep an eye on divide-by-zero when baseline cells can be empty.

Use IFERROR only after you understand what you are hiding from reviewers.

Step-by-step

  1. Put baseline values in column A and new values in column B starting row 2.
  2. In C2 enter =(A2-B2)/A2 and fill down.
  3. Format column C as Percentage with the precision your style guide requires.
  4. Add a column for notes when baselines differ by row.

Quick sample

A2=200, B2=150 → C2 shows 0.25 → 25% when formatted as percent.

FAQ

Should I multiply by 100 in the cell?
Not if you use percent number format; the spreadsheet displays 100× the decimal.
Pivots?
Aggregate first, then compute decrease on aggregated baselines if that matches your metric definition.

Conclusion

Summary

Excel shines at repeatability; narrative still needs the baseline in words.

Cross-check tricky rows on the home calculator when something looks off.

Open the calculator

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