Percentage increase:
work out growth from old to new

Percentage increase formula

Percentage increase tells you how much a number has grown compared with where it started. Subtract the old value from the new one, divide by the old value, then multiply by 100.

It is a relative measure. An increase of ₹500 means very different things on a ₹2,000 bill and on a ₹2,00,000 loan, and the percentage is what makes the two comparable.

The old value is the denominator, always. Dividing by the new value is the single most common slip, and it understates the growth.

How to calculate percentage increase step by step

1. 1Write down the old (starting) value and the new value in the same unit.
2. 2Subtract old from new to get the absolute increase.
3. 3Divide that increase by the old value.
4. 4Multiply by 100 and add the % sign.

Make sure both values describe the same thing over comparable periods. Comparing one month's sales with another month's total for a quarter will give a percentage that means nothing.

Keep the full decimal until the end and round once. A calculator on this page handles the arithmetic, but it helps to be able to sanity-check it by hand: if the new value is double the old one, the answer should be 100%.

Worked example: a salary hike

Suppose your monthly salary goes from ₹50,000 to ₹56,500. The question is how big the raise is as a percentage.

The same steps work for bills. If an electricity bill climbs from ₹1,850 to ₹2,220, the increase is ₹370, and ₹370 ÷ ₹1,850 × 100 = 20%.

Use the same steps for any growth figure, whether it is a hike, rent, a fuel bill or monthly website visits. In the visits case, going from 8,000 to 10,000 is 2,000 ÷ 8,000 × 100 = 25%.

How to add a percentage increase to a number

Often you know the old value and the percentage, and need the new value, for example when a landlord announces a rent revision or a vendor sends a revised quotation. Convert the percentage into a multiplier and multiply.

A supplier raises a ₹1,200 item by 15%. The multiplier is 1.15, so the new price is ₹1,200 × 1.15 = ₹1,380.

Going backwards works the same way. If a value is ₹56,500 after a 13% rise, divide by 1.13 to find the original: ₹56,500 ÷ 1.13 = ₹50,000. Do not subtract 13% from ₹56,500, because the 13% was measured on the smaller starting number.

Quick ways to estimate an increase in your head

You will not always have a calculator to hand, and a rough estimate catches typing errors. Start from 10%, which is the value with the decimal point moved one place left.

• 10% of ₹1,200 is ₹120.
• 5% is half of that, ₹60.
• 15% is 10% plus 5%, so ₹120 + ₹60 = ₹180, which matches the ₹180 increase found earlier.
• 1% is the value divided by 100, so 7% is seven of those.

The same logic works for targets. To lift monthly sales from ₹2,40,000 to ₹3,00,000, you need (₹3,00,000 − ₹2,40,000) ÷ ₹2,40,000 × 100 = 25% growth. Knowing the percentage turns a vague ambition into something you can plan month by month.

Where percentage increase goes wrong

• Rises and falls do not cancel. A 20% rise takes 100 to 120, and a 20% fall from there lands on 96, not 100. After a 20% fall to 80, you need a 25% rise to get back to 100.
• Percentage points are not percent. A rate that moves from 6% to 8% has risen by 2 percentage points but by 33.3% in relative terms.
• A rise from zero has no percentage. Dividing by an old value of 0 is undefined, so report the absolute change instead.
• Large percentages can hide small amounts. A jump from 2 to 6 enquiries is 200%, yet it is only four more enquiries.
• Stacked increases multiply. Two successive 10% rises give 1.10 × 1.10 = 1.21, a 21% rise, not 20%.
• Rounding too early. Rounding 13.04% to 13% is fine for a headline, but carry the exact figure forward if you will use it in another calculation.

A related trap is the comparison with an average. If a month is 12% above the yearly average, that is a different statement from being 12% above the previous month, so say which base you used.

Choose the base carefully when comparing years. If you compare this year with last year, last year is the old value. If you compare last year with this year by mistake, the answer changes sign and size.

When you report growth, give the absolute change and the percentage together. The percentage shows the pace of growth, and the absolute number shows how much it matters.

Using the result to compare and plan

Before you quote a percentage to anyone, run through three quick checks:

• Is the old value the right starting point, and is it the same kind of figure as the new one?
• Does the direction make sense? If the new value is larger, the answer must be positive.
• Does a rough mental estimate agree with the exact figure to within a point or two?

A percentage lets you compare changes on different scales. A ₹500 rise on a ₹2,500 bill is bigger, proportionally, than a ₹2,000 rise on a ₹50,000 salary, even though the second looks larger in rupees.

In a negotiation, the percentage also frames the ask. A request for a 10% raise on a ₹60,000 salary is ₹6,000 a month, and writing it both ways makes the conversation concrete.

For planning, apply the same percentage to several years only after checking whether it is realistic. A 13% rise each year compounds quickly. If the figure fell instead of rising, use the percentage decrease method, and to describe either direction in one go, see the percentage change guide.