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％ Percentage Calculator

X% of Y, X is what % of Y, percentage change, increase/decrease by %, reverse percentage and % difference — all in one.

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All-in-one percentage calculator

Percentages appear in every business conversation — GST at 18%, a 12% salary hike, sales up 15% over last year, a 7% TDS on rent, a 28% discount. This calculator covers all seven everyday percentage questions in one place and shows the formula used, so you can verify the answer or teach it.

The seven modes

  • What is X% of Y? — 18% of ₹25,000 = ₹4,500. Used for GST, TDS, commission, tips.
  • X is what % of Y? — ₹4,500 is 18% of ₹25,000. Used for expense ratios, attendance, marks.
  • % change from A to B — sales grew from ₹80,000 to ₹92,000 = +15%. Used for growth, inflation, YoY comparisons.
  • Increase Y by X% — ₹25,000 + 12% = ₹28,000. Used for salary hikes, price revisions.
  • Decrease Y by X% — ₹25,000 − 20% = ₹20,000. Used for discounts, depreciation.
  • Reverse percentage — if ₹28,000 is after a 12% hike, the original was ₹25,000. Used to strip GST from an inclusive price or find pre-hike salary.
  • % difference — between two independent values relative to their average, for comparing two vendors or branches.

Formulas

  • X% of Y = Y × X ÷ 100
  • X as % of Y = X ÷ Y × 100
  • % change = (New − Old) ÷ Old × 100
  • Increase/decrease = Y × (1 ± X ÷ 100)
  • Original before change = Result ÷ (1 ± X ÷ 100)
  • % difference = |A − B| ÷ ((A + B) ÷ 2) × 100

Worked example — reverse percentage

A restaurant bill shows ₹1,260 "inclusive of 5% GST". The pre-tax amount is not ₹1,260 − 5% (= ₹1,197) but ₹1,260 ÷ 1.05 = ₹1,200, with GST of ₹60. Subtracting the percentage instead of dividing is the most common percentage error in invoices and salary negotiations.

Common pitfalls

  • A 20% rise followed by a 20% fall leaves you 4% below the start (1.2 × 0.8 = 0.96).
  • Percentage points are not percentages: GST moving from 12% to 18% is a 6-point rise but a 50% increase in the tax rate.
  • % change is undefined when the old value is zero — the tool will tell you.

The quick table at the bottom lists 1% to 50% of your base value, along with the increased and decreased figures, handy for GST slabs (5, 12, 18, 28) and TDS rates (1, 2, 10).

Frequently Asked Questions

How do I remove GST from a price that includes it?

Divide by (1 + rate). For 18% GST: price ÷ 1.18. Use the "reverse percentage" mode with an increase of 18%.

How do I calculate percentage increase between two numbers?

(New − Old) ÷ Old × 100. From 80,000 to 92,000: 12,000 ÷ 80,000 = 15% increase.

What is the difference between percentage change and percentage difference?

Percentage change has a clear "before" and "after" and uses the old value as the base. Percentage difference compares two values with no order, using their average as the base.

Why is 20% off then 20% on not the original price?

Because the second 20% is calculated on a smaller base. ₹100 − 20% = ₹80; ₹80 + 20% = ₹96.

Disclaimer: This tool is for general information and estimation only. Tax rates and rules change — verify with official sources or a professional before acting. Read full disclaimer.