Skip to main content
SheetTutor.
← All tasks↓ Sample workbook

Calculate percentage change from a positive base

Read-only

Step-by-step guide · read-only · Selected D2

Loading your interactive spreadsheet…

Preparing the worksheet and formulas…

Data & tools
Task requirements

Fill D2:D6 with (current − previous) / previous when the previous value is positive. Return Review base otherwise.

Follow the highlighted cells. Switch to Your turn to edit. Answer cells: D2, D3, D4, D5, D6. Browser calculations may differ from your Excel version.

Selection & formula search

Practice stays on this device. No worksheet data is uploaded.

Notes & examples
About this lesson
Count & summarize6 min·Starter

Compare old and new values, distinguish growth from decline, and handle zero or negative starting values explicitly.

THE QUICK ANSWER01

Subtract the previous value, then divide by that same previous value. A result of 0.25 means a 25% increase. This task sends zero and negative bases for review.

ƒx=IF(B2<=0,"Review base",(C2-B2)/B2)
For the example data
D2 0.25D3 -0.25D4 0D5 Review baseD6 Review base

The formula uses the interactive worksheet above. Adjust ranges and criteria for your own data.

UNDERSTAND THE IDEA

How it works

Change rate and percentage points

Going from a 20% conversion rate to 25% is a five-percentage-point increase. Its relative increase is 25%. Those are different measures; label the one you intend to report.

Why nonpositive bases are flagged

Dividing by zero is undefined. Negative starting values can make an apparently improved result produce a confusing sign. We return Review base for both cases instead of choosing a financial interpretation silently.

Keep the value numeric

The result stays a decimal number so it can be reused in calculations. Format the cell as a percentage when you need a percent sign. Do not multiply by 100 and then apply Percentage formatting again.

Read the full step-by-step walkthrough
  1. Identify the baseline

    The previous value is the denominator. Changing it changes the comparison you are making.

    B2
  2. Find the difference

    Current minus previous is positive for growth, negative for decline and zero for no change.

    C2-B2
  3. Divide by the previous value

    This turns an absolute difference into a change relative to the starting value.

    (C2-B2)/B2
  4. Check whether the base is usable

    A zero base cannot be used as the denominator. This example also flags negative bases because their interpretation needs a business decision.

    IF(B2<=0,"Review base",…)
  5. Read the decimal as a percentage

    The sheet shows decimal results: 0.25 is 25%, and -0.25 is -25%. In Excel, apply Percentage formatting instead of multiplying the formula by 100.

WHEN SOMETHING LOOKS OFF

Things to watch

The denominator is the new value

That measures the difference relative to the current value, not change from the previous value.

The result is 100 times too large

Percentage formatting already displays a decimal as a percentage.

Zero becomes 0%

No baseline is not the same as no change. Return the review message for zero or negative bases.

About this example

Published examples, formula filling and practice checks were tested in Chrome on October 13, 2026. Tests cover the supplied datasets and stated input rules, not every possible formula. These workbooks have not yet been independently recalculated in Microsoft Excel or Google Sheets.

Browser: testedExcel: not verifiedGoogle Sheets: not verified

Content version 2. Practice checks compare calculated results across different datasets; they do not certify every possible formula.

Reference material