InstantToolsPro
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InstantToolsPro
Find percentages, percentage increase or decrease, and what percent one number is of another — instantly, no signup.
Choose % of a number, X is what %, or % increase/decrease.
Type the two numbers relevant to your chosen calculation mode.
The answer updates instantly as you type, with no need to click calculate.
Tap a different tab to switch calculation type without losing your place.
Percentages come up constantly in everyday life – discounts at a store, tax on a bill, marks in an exam, or tracking how much a price or value has changed over time. InstantToolsPro's percentage calculator covers the three most common percentage questions people need answered, switching instantly between modes so you don't have to remember a different formula for each one.
This mode answers the question "what is X% of Y?" – for example, what is 20% of 500? The calculation is straightforward: multiply the number by the percentage, then divide by 100. So 20% of 500 is (20 × 500) ÷ 100 = 100. This is the mode you'd use to work out a tip amount, a tax charge, or a discount value before it's subtracted from a price.
This mode flips the question around – instead of starting with a percentage, you have two actual numbers and want to know what percentage one represents of the other. For example, if you scored 50 out of 200 marks, what percentage is that? The formula divides the first number by the second, then multiplies by 100: (50 ÷ 200) × 100 = 25%. This mode is commonly used for exam results, survey response rates, or working out what share of a total budget a specific expense represents.
This mode calculates how much something has changed, expressed as a percentage of the original value. The formula is ((New Value − Original Value) ÷ Original Value) × 100. If a price went from 100 to 150, that's an increase of ((150 − 100) ÷ 100) × 100 = 50%. If the new value is smaller than the original, the result comes out negative, correctly indicating a decrease. This mode is the one most people reach for when comparing salary hikes, rent increases, or how much a stock or asset has gained or lost in value.
A shirt originally priced at ₹1,200 is on sale with a 30% discount — using Mode 1, 30% of 1,200 is ₹360, so the discounted price is ₹840. A restaurant bill of ₹850 with an 18% GST charge adds 18% of 850, which is ₹153, bringing the total to ₹1,003. If your monthly rent went from ₹15,000 to ₹16,500, Mode 3 shows that's a 10% increase — useful context when negotiating a renewal or comparing it against inflation. These small mental-math shortcuts become second nature once you've run a few real numbers through the calculator instead of just reading the formulas.
One of the most common percentage mistakes is confusing a percentage change with a change in percentage points. If an interest rate moves from 5% to 7%, that's a 2 percentage point increase, but it's actually a 40% increase in the rate itself — because (7 − 5) ÷ 5 × 100 = 40%. News headlines and financial reports often use these two phrases loosely, and mixing them up can make a change look much smaller (or larger) than it actually is. When in doubt, Mode 3 of this calculator will give you the correct percentage change, not just the raw point difference.
Sometimes you know the result of a percentage calculation but need to find the original number. For example, if a discounted price of ₹840 reflects a 30% discount, the original price can be found by dividing 840 by (1 − 0.30), which gives ₹1,200. This "reverse" calculation comes up often when checking whether a store's advertised discount matches the actual price difference, or when reconstructing a pre-tax amount from a tax-inclusive total.
Every percentage has an equivalent decimal and fraction form, and switching between them is often the fastest way to do quick mental math without a calculator. 25% equals 0.25 as a decimal and ¼ as a fraction; 50% equals 0.5 and ½; 75% equals 0.75 and ¾. To convert any percentage to a decimal, divide by 100 — so 8% becomes 0.08. To go the other way, multiply a decimal by 100 and add a percent sign. This conversion is exactly what happens under the hood in Mode 1 of this calculator, and knowing it by heart makes it much easier to sanity-check whether a result the calculator gives you looks right.