How to Do Percentages in Excel

To do percentages in Excel, write the calculation as ordinary arithmetic first — =42/50 for a part of a total — then select the cell and click Percent Style on the Home tab. The formula does the maths; the button only changes how the answer is displayed. Excel still stores 0.84 behind the 84% you see.

If you have searched how to do percentages in Excel and ended up with a cell reading 8400.00%, the cause is almost always that formatting was applied to a number that was already a whole figure. Excel treats a percentage as a display format, not as a calculation.

Once that distinction is clear, every percentage task in a spreadsheet becomes one plain formula plus one button. The three calculations below cover nearly all of them.

How to do percentages in Excel: the formula, then the button

1. Click an empty cell and type the calculation as ordinary arithmetic. For a part of a total, that is the part divided by the whole: =42/50.

2. Press Enter. Excel returns 0.84. That is already the right answer — it is simply not yet dressed as a percentage.

3. Select the cell again. On the Home tab, in the Number group, click Percent Style, the % button. The cell now reads 84%.

4. Use Increase Decimal or Decrease Decimal, immediately beside it, to set how many decimal places appear.

Order matters. Microsoft's documentation notes that applying percent formatting to a cell that already contains 10 multiplies it by 100 and displays 1000.00%, and advises calculating the value as a decimal first — =10/100 returns 0.1, which displays as 10%. An empty cell formatted as percent beforehand behaves differently: typing either 10 or 0.1 produces 10.00%.

Percent of a total down a whole column

For a single row the division is enough. Across a column, the denominator has to stay fixed or it will drift down the sheet as you copy.

1. Put the total in its own cell — say B12.

2. In the first result cell, type =B2/$B$12. The dollar signs lock the reference so it does not move when copied.

3. Copy the formula down the column, then apply Percent Style to the whole range at once.

On Windows you can select the reference in the formula bar and press F4 to cycle between reference types. Microsoft's reference page does not name a Mac equivalent, so on a Mac it is simplest to type the dollar signs yourself. If you are scrolling a long column, it helps to keep the header row visible while you work.

Percent change between two numbers

The shape is always the same: new value minus old value, divided by the old value.

1. For an increase from 2,342 to 2,500, enter =(2500-2342)/2342. Excel returns 0.06746, which displays as 6.75% once formatted.

2. For a decrease from 2,500 to 2,425, enter =(2425-2500)/2500. That returns -0.03000, shown as -3.00%.

Decreases come back negative, which is the intended behaviour — the sign is what distinguishes a fall from a rise. If you are tracking a figure over several periods, these results plot cleanly as a line graph.

Increase or decrease a number by a percent

This one does not need the Percent Style button at all, because the answer is a quantity rather than a proportion.

1. To add 25% to 113, enter =113*(1+0.25). The result is 141.25.

2. To take 25% off 113, enter =113*(1-0.25). The result is 84.75.

To work backwards from a discounted figure to the original, divide instead: a $15 sale price at 25% off is =15/0.75, or 20. For currency, Microsoft points to the Accounting Number Format button rather than Percent Style.

The keyboard shortcut, the dialog and the newer function

Ctrl+Shift+% applies percent formatting without reaching for the ribbon.

For finer control, open Format Cells and choose Percentage in the Category list. On Windows, the launcher button beside Number in the Number group opens it. On a Mac, click the Number Format arrow next to General and choose More Number Formats. The Decimal places box there takes 0 if you want 10% rather than 10.00%.

Microsoft 365 subscribers also have a dedicated function, PERCENTOF, written as =PERCENTOF(data_subset,data_all). Microsoft describes it as logically equivalent to =SUM(data_subset)/SUM(data_all) and lists it under Excel for Microsoft 365, so it will not appear in perpetual-licence versions. The division formula above works everywhere.

The button names are the same on Mac and Windows: Microsoft's Excel for Mac guidance uses Home, Percent Style, Increase Decimal and Decrease Decimal exactly as the Windows pages do.

What Percent Style does not do

It does not change the stored value. A cell displaying 84% still contains 0.84, and that decimal is what any formula referring to the cell will read. This is usually what you want, but it surprises people who expect to multiply by a visible 84.

It also does not round anything. Reducing the decimals shown turns 6.746% into 6.75% on screen while the full value stays intact underneath — useful for display, misleading if you assume the figure has actually been rounded.

And it is not the same as typing a percent sign as text. A cell containing the characters "84%" entered as text cannot be calculated with.

Common questions

Why does my cell show 1000.00%? The cell held 10 before the format was applied, and Excel multiplied it by 100. Replace the contents with a decimal — 0.1, or a formula such as =10/100.

Can I use a percentage result in another formula? Yes, and you should reference the cell directly. Because the stored value is the decimal, =A1*B1 where A1 shows 84% behaves correctly without any conversion.

How do I show whole percentages with no decimals? Click Decrease Decimal until they disappear, or set Decimal places to 0 in Format Cells.

If the Percent Style button isn't there

A narrow window collapses the ribbon. The Number group folds into a single button you click to expand — or skip the ribbon entirely with Ctrl+Shift+%.

If the shortcut and the button both do nothing, the sheet is probably protected, which blocks formatting changes. Formatting is also unavailable while a cell is in edit mode; press Enter or Esc first, then select the cell and try again.