Percentage Calculator
Calculate percentages, increases, decreases and differences — free, instant, with step-by-step explanation
Result
Step-by-step explanation
What is this Percentage Calculator?
This free percentage calculator solves four different types of percentage problems instantly — and shows a clear step-by-step explanation for every result so you understand exactly how the answer was reached. Whether you are a student checking exam marks, a shopper calculating a discount, a business owner tracking sales growth, or an employee comparing salary hikes, this tool covers every percentage calculation you will ever need.
Unlike a basic calculator where you have to remember formulas, this tool has four dedicated modes — each designed for a specific type of percentage question — so you just pick the right mode, enter your numbers, and get the answer with a full explanation.
How to use this Percentage Calculator — all 4 modes explained
- Basic % mode — "What is X% of Y?": Use this when you know a percentage and a number and want the value. Example: What is 15% of ₹2,500? Enter 15 in the % field and 2500 in the number field. Answer: ₹375. Used for: calculating tip amounts, finding discount values, GST on a price, commission earned.
- Increase mode — "X increased by Y%": Use this when a value goes up by a percentage. Example: Your salary of ₹45,000 increases by 12%. Enter 45000 and 12. Answer: ₹50,400. Used for: salary hikes, price rises, investment growth, population increase.
- Decrease mode — "X decreased by Y%": Use this to find a value after a percentage reduction. Example: A phone priced ₹18,000 is on 25% sale. Enter 18000 and 25. Answer: ₹13,500. Used for: shopping discounts, price drops, depreciation, cost reductions.
- Difference mode — "% change from X to Y": Use this when you have two values and want to know the percentage change between them. Example: Your marks went from 68 to 85 out of 100. Enter 68 as original, 85 as new. Answer: +25% increase. Used for: comparing scores, revenue growth, stock price changes, before-after comparisons.
Real worked examples for each mode
- Basic %: A restaurant bill is ₹1,840. You want to leave a 10% tip. What is 10% of ₹1,840? Answer: ₹184. Total to pay: ₹2,024.
- Increase: A product costs ₹5,000. The price is increased by 8% due to GST change. New price = ₹5,000 + 8% of ₹5,000 = ₹5,000 + ₹400 = ₹5,400.
- Decrease: Flipkart shows ₹3,999 MRP with 35% off. Sale price = ₹3,999 − 35% of ₹3,999 = ₹3,999 − ₹1,399.65 = ₹2,599.35.
- Difference: Your company's revenue was ₹12 lakh last year and ₹15.6 lakh this year. Percentage growth = (₹15.6L − ₹12L) ÷ ₹12L × 100 = 30% growth.
Key features
- 4 calculation modes: Basic %, Increase, Decrease, and Difference — covering every real-world scenario
- Step-by-step explanation: Every result shows the formula and how numbers were applied — not just the answer
- Handles decimals: Works with decimal percentages like 8.5%, 12.5%, 0.25% — not just whole numbers
- Instant results: Results update as you type — no button needed once values are entered
- 100% private: All calculations run in your browser — no data stored or sent anywhere
Percentage mistakes everyone makes — and how to avoid them
Percentages are one of the most used — and most misunderstood — calculations in everyday life. Most errors happen not because people can't do math, but because they use the wrong formula for the situation or confuse the base value. Here are the four most common mistakes, with the correct calculation shown for each.
Mistake 1 — Wrong base value
The base value (the number you apply the percentage TO) must always be the original or reference value — not the new one. If a product costs ₹1,000 and its price rises to ₹1,200, the percentage increase is calculated on ₹1,000 (original), giving 20%. If you accidentally use ₹1,200 as the base, you get 16.67% — which is wrong. This is the single most common percentage error in finance and business.
Mistake 2 — Adding stacked discounts
If a product has 20% off and then an additional 10% off, most people think the total discount is 30%. It is actually only 28%. Here is why: 20% off ₹1,000 = ₹800. Then 10% off ₹800 = ₹720. The total discount is ₹280, which is 28% of the original ₹1,000 — not 30%. Each discount is applied to the already-reduced price, not the original. This mistake costs shoppers and sellers real money every day.
Mistake 3 — Reversing increase and decrease
If a price increases by 25%, it does NOT decrease back to the original with another 25% decrease. Example: ₹1,000 increased by 25% = ₹1,250. ₹1,250 decreased by 25% = ₹937.50 — not ₹1,000. To undo a 25% increase, you need to decrease by 20% (1 − 1/1.25 = 0.20). This is why sale prices that claim to "restore original prices" often don't fully restore them.
Mistake 4 — Percentage points vs percentage
When a bank's interest rate goes from 6% to 8%, it has increased by 2 percentage points — but the percentage increase is actually 33.33% (because (8−6)÷6×100 = 33.33%). Politicians and media often say "increased by 2%" when they mean "2 percentage points," which creates confusion. In financial and academic contexts, always clarify whether you mean percentage points or percentage change.
Where percentages are used in daily life in India
Shopping and e-commerce: Every discount, cashback offer, and "X% off on first order" requires a percentage calculation. Knowing how to verify a discount protects you from misleading MRP markups where the original price is inflated before applying the discount.
Exams and marks: Converting marks to percentage, calculating how much you need to score to reach a target percentage, or understanding a grade cutoff — all require the Difference or Basic % modes in this calculator.
Salary and finance: Calculating a percentage hike on your CTC, understanding that a 10% increment on ₹6 lakh is ₹60,000 (not ₹6,000), or tracking whether your savings rate is improving — all are everyday percentage problems.
Business and GST: Calculating profit margin percentage, markup vs markdown, commission as a percentage of sales, or verifying that GST charged is the correct percentage of the pre-tax value — businesses rely on accurate percentage calculations constantly.
Loans and interest: Understanding that an 8.5% annual interest rate on a ₹10 lakh loan costs ₹85,000 in simple interest per year — or using EMI calculator for compound calculations — starts with a percentage calculation.
Free, instant, step-by-step explanation included.
Frequently asked questions
How do I calculate 20% of 500?
Select Basic % mode, enter 20 in the percentage field and 500 in the number field, then click Calculate. Result: 100. The formula is: (20 ÷ 100) × 500 = 0.20 × 500 = 100. This is the most commonly used percentage calculation — it answers "what is X% of Y?" Use it for finding discount amounts (20% off ₹500 = ₹100 off, so you pay ₹400), calculating tips, finding GST amounts, or splitting bills. Remember: the percentage always goes in the first field, and the number you are applying it to goes in the second.
How do I calculate percentage increase from 200 to 250?
Select Difference mode, enter 200 as the Original value and 250 as the New value, then click Calculate. Result: 25% increase. The formula is: ((New − Original) ÷ Original) × 100 = ((250 − 200) ÷ 200) × 100 = (50 ÷ 200) × 100 = 25%. Important: always use the original (earlier) value as the base — not the new value. A common mistake is dividing by 250 instead of 200, which gives 20% (wrong). Use this mode anytime you want to know how much something changed as a percentage — salary hike, revenue growth, price change, weight loss progress.
What is 30% off on ₹1,500?
Select Decrease mode, enter 1500 as the number and 30 as the percentage, then click Calculate. Result: ₹1,050. The formula is: ₹1,500 − (30% × ₹1,500) = ₹1,500 − ₹450 = ₹1,050. The discount amount itself is ₹450, and the price you pay is ₹1,050. Use this mode for any scenario where a value is reduced by a percentage — sale prices, depreciation, cost reductions, or even calculating weight loss (e.g., lost 5% of 80kg = 76kg remaining).
What is the difference between Increase mode and Difference mode?
Increase mode answers: "I have a starting number and I want to increase it by a known percentage — what is the result?" For example: my salary is ₹40,000 and I got a 15% hike — what is my new salary? (Answer: ₹46,000.) You already know the percentage and want the new value. Difference mode answers: "I have two values — what is the percentage change between them?" For example: my salary was ₹40,000 and is now ₹46,000 — what percentage increase is that? (Answer: 15%.) You already have both values and want the percentage. Use Increase/Decrease when you know the percentage; use Difference when you know both values.
How do I find what percentage one number is of another?
Use Basic % mode but think of it differently: "75 is what percentage of 300?" The formula is (75 ÷ 300) × 100 = 25%. So 75 is 25% of 300. In the tool, you can verify this by entering 25 as the percentage and 300 as the number — the result should be 75. Alternatively, use Difference mode with Original = 0 and think of it as a ratio. This type of question comes up when checking what percentage of marks you scored (e.g., 87 out of 120 = (87÷120)×100 = 72.5%), what share of a budget was spent, or what fraction of a target has been achieved.
Does the calculator show how the result was calculated?
Yes — this is one of the key features that sets this tool apart. Every result includes a step-by-step explanation box that shows exactly which formula was used and how your numbers were plugged into it. For example, if you calculate 15% of 2,500 in Basic % mode, the explanation shows: "15% of 2,500 = (15 ÷ 100) × 2,500 = 0.15 × 2,500 = 375." This means you are not just getting an answer — you are learning the method, which you can apply manually in the future. Students preparing for exams, people learning financial math, and anyone who wants to verify calculations will find this especially useful.
Can this calculator handle decimal percentages like 8.5% or 12.75%?
Yes — all four modes accept decimal values in both the percentage and number fields. You can calculate 8.5% of ₹45,000 (= ₹3,825), find what ₹60,000 increased by 12.5% becomes (= ₹67,500), or check the percentage change from 4.2 to 5.7 (= 35.71% increase). This is particularly useful for finance calculations involving interest rates, GST at special rates (like 0.25% on rough diamonds or 3% on gold), or exam percentages that involve non-round numbers. Simply type the decimal value — the tool handles it correctly.