How to Calculate Percentage Increase in Excel and Google Sheets (Formulas + Examples)

Whether you are checking how much your shop’s sales grew this month, working out a rent increase before signing a new lease, or tracking how fast your channel is gaining subscribers, percentage increase is one of those calculations that keeps popping up. Shop owners use it to measure growth, students meet it in almost every maths exam, freelancers use it to justify raising their rates, and marketers live by it when they report campaign results.

The good news is that you do not need a calculator, a maths degree, or a special add-in. If you can type into a spreadsheet, you already have everything you need. This guide shows you the one formula that does the job in both Microsoft Excel and Google Sheets, walks you through it step by step, and works through three real-world examples so you can see exactly how it behaves.

The Only Formula You Need

The entire calculation comes down to this single formula:

=(New Value – Old Value) / Old Value

Type it into any cell, press Enter, and format the result as a percentage. That is genuinely all there is to it.

Here is what each part does, in plain words. (New Value – Old Value) finds the size of the change: if sales went from $4,200 to $5,040, the change is $840. / Old Value then measures that change against your starting point: $840 / $4,200 = 0.2. Formatting the result as a percentage simply multiplies by 100 for display, turning 0.2 into 20%.

Why divide by the old value rather than the new one? Because an increase is always measured against where you started. An $840 rise means something very different when you started at $4,200 compared with starting at $84,000 – and dividing by the old value is what captures that context.

One more thing worth knowing: this formula never changes. Whether you are comparing sales, prices, weights, or website traffic, you always subtract the old from the new and divide by the old. Memorise =(New Value – Old Value) / Old Value once, and you can apply it to any numbers life throws at you – no variations to learn.

Step by Step in Excel

Let us build it properly with cell references, so the formula updates itself whenever your numbers change.

1. Type your old value into cell A2 – for example, 4200.
2. Type your new value into cell B2 – for example, 5040.
3. Click cell C2 and type =(B2-A2)/A2, then press Enter. You will see 0.2.
4. With C2 still selected, click the % button in the Home tab (in the Number group). The cell now shows 20%.
5. If you want more precision, click Increase Decimal to show 20.0% or 20.00%.

That is the whole workflow. To reuse it every month, just overwrite the numbers in A2 and B2 – C2 recalculates instantly. You can also drag the fill handle down from C2 to apply the same formula to a whole column of old and new values.

Google Sheets users follow exactly the same steps. Type the same formula, press Enter, then choose Format > Number > Percent (or click the % button in the toolbar). Cell references, auto-fill, and decimal controls all work the same way.

A handy extra: once the formula is in place, select cell C2, click the Format Painter (the paintbrush icon), and drag across other cells to copy just the percentage formatting. And if you share the spreadsheet with colleagues, consider locking the formula cells so nobody overwrites them by accident.

3 Worked Examples

Seeing the formula with real numbers makes everything click. Here are three situations you will actually run into.

Example 1 – Monthly sales growth. A small online shop made $4,200 in January and $5,040 in February. The calculation is =(5040-4200)/4200, which is 840/4200 = 0.2, formatted as 20%. Sales grew by 20% month over month – a healthy result worth celebrating.

Example 2 – Rent increase. Your landlord raises the monthly rent from $800 to $880. The calculation is =(880-800)/800, which is 80/800 = 0.1, formatted as 10%. That is a 10% increase – useful to know before you compare it with inflation or negotiate.

Example 3 – Social media followers. Your account grows from 1,250 followers to 1,900. The calculation is =(1900-1250)/1250, which is 650/1250 = 0.52, formatted as 52%. A 52% jump in followers – the kind of number that looks great in a media kit or a client report.

4 Mistakes That Break the Formula

The formula is simple, but these four slips catch almost everyone at least once.

1. Forgetting to format as a percentage. The formula returns 0.2, which is mathematically correct – but if you expected “20%” and saw “0.2”, it looks broken. Always click the % button after entering the formula. If you see a tiny decimal where you expected a whole number, this is almost certainly the cause.
2. Dividing by zero. If the old value is 0 – say, your very first month of sales – the formula tries to divide by zero and Excel shows #DIV/0!. There is no meaningful percentage increase from zero, so handle it with an IF check: =IF(A2=0,”-“,(B2-A2)/A2). This shows a dash instead of an ugly error.
3. Referencing the wrong cells after sorting. This one bites when you sort a table after writing your formulas. A formula pointing at B2 and A2 normally follows the data as it moves – but if you sorted only one column, or pasted values over the top, the references can end up pointing at the wrong rows. After any sort, glance at a couple of results to confirm they still make sense.
4. Hunting for a separate “decrease” formula. You do not need one. The same formula handles decreases automatically – the result simply comes out negative. A drop from $800 to $720 gives =(720-800)/800 = -0.1, which formats as -10%. A negative result means a decrease; the maths is identical.

Try It Faster

If you just need the answer without opening a spreadsheet, our free percentage calculator does it instantly. Type in your old and new values and it works out the increase for you – handy when you are on your phone or away from your desk. But for tracking growth month after month, nothing beats the spreadsheet formula above: set it up once and it keeps working for you forever.

Calculating percentage increase in Excel or Google Sheets really is a one-line skill: subtract the old value from the new, divide by the old, and format as a percentage. Learn it once and you will use it every week – for sales, prices, followers, and anything else that grows. Try it with your own numbers now, and you will never reach for a calculator for this again.