Percentage Calculator
Three modes — find a percentage, find what percent X is of Y, or calculate percentage change
Mode 1
What is X% of Y?
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% of
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Mode 2
X is what % of Y?
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of
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Mode 3
Percentage change from X to Y
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Formulas
Mode 1: Result = (X / 100) × Y
Mode 2: Result = (X / Y) × 100
Mode 3: Change = ((Y − X) / |X|) × 100
What is a Percentage Calculator?
Percentages are one of the most commonly used mathematical concepts in everyday life — from discounts and taxes to exam scores and growth rates. This calculator covers three essential modes: finding X% of a number, determining what percentage one number is of another, and computing percentage change between two values.
Understanding percentages helps in comparing data, tracking progress, and making informed financial decisions. All three modes are solved instantly with step-by-step clarity.
lightbulb Example Calculations
Scenario: Mr. Arjun, HR Manager at Wipro — received a salary of ₹80,000 last month and ₹20,000 performance bonus. He wants to know: (1) what % is the bonus of salary, (2) his total hike from ₹72,000 to ₹80,000
1Mode 1: 20% of 500 = (20/100) × 500 = 100
2Mode 2: 80 of 400 = (80/400) × 100 = 20%
3Mode 3: Change from 200 to 250 = ((250−200)/200) × 100 = +25%
✓ All three modes solved instantly
help_outlineHow to Use the Percentage Calculator
- Select the mode matching your question: Mode 1 — What is X% of Y? | Mode 2 — X is what % of Y? | Mode 3 — % change from X to Y.
- For Mode 1: Enter the percentage (X) and the total value (Y). Example: 20% of 500 = 100.
- For Mode 2: Enter the part (X) and the whole (Y). Example: 80 of 400 = 20%.
- For Mode 3: Enter the old value (X) and new value (Y) to find the percentage increase or decrease between them.
- Results appear live as you type — no button click needed.
Benefits
- Three calculation modes in one place — covers discounts, exam scores, salary hikes, and GST in a single tool
- Reverse calculation built in — find the original value when you know the percentage result
- Works with decimals for precise results (e.g., 8.5% of ₹3,750)
- Formula displayed alongside result for learning and self-verification
- No sign-up required — instant, private calculations in your browser
Key Terms
- Percent (%)
- Latin "per centum" — per hundred. 25% = 25/100 = 0.25 as a decimal
- Part
- The specific quantity being expressed as a fraction of the whole (numerator)
- Whole / Total
- The base or reference value representing 100% (denominator)
- Percentage Change
- Relative shift between two values: ((New − Old) / Old) × 100
- Percentage Point
- Absolute difference between two percentages — 8% to 10% is 2 percentage points (not 25% change)
quizFrequently Asked Questions
What is the difference between percent and percentage point?
A "percent" change is relative to the base value: if the interest rate rises from 8% to 10%, that is a 25% increase (2/8 × 100). A "percentage point" is the absolute numerical difference: the rate rose by 2 percentage points. In finance and RBI policy, rate changes are almost always described in percentage points or basis points (1 basis point = 0.01%), not relative percentages.
How do I find the original price before a discount?
Use reverse Mode 1. If you paid ₹800 after a 20% discount, the original price = ₹800 / (1 − 0.20) = ₹1,000. Equivalently: ₹800 is 80% of original → original = ₹800 / 0.80 = ₹1,000. This reverse calculation also applies to GST-inclusive prices — to find the pre-GST price: Inclusive ÷ (1 + GST rate/100).
How do I calculate the percentage of marks scored?
Use Mode 2: enter marks obtained as X and total maximum marks as Y. Example: scored 450 out of 500 → (450 / 500) × 100 = 90%. For multiple subjects with different maximum marks, sum all marks obtained and all maximum marks separately, then compute overall percentage. Never average subject-wise percentages when maximums differ.
How is GST calculated using percentages?
GST amount = (GST rate / 100) × Base price. For 18% GST on ₹2,000: (18/100) × 2,000 = ₹360 tax; total = ₹2,360. To extract base from a GST-inclusive price: Base = Inclusive price / (1 + rate/100). For ₹2,360 inclusive of 18% GST: Base = ₹2,360 / 1.18 = ₹2,000. Use the GST Calculator for full CGST/SGST/IGST split.
Can Mode 3 handle negative starting values?
Yes. The formula uses |Old| (absolute value of old) as the denominator. So % change from −50 to −20 = (−20 − (−50)) / |−50| × 100 = 30/50 × 100 = +60%. This correctly captures loss reduction, temperature changes, and debt paydown scenarios where values move from negative toward zero or positive.