Quick Percentage Helper

Percentage Helper

Percentage Helper

How to Use This Percentage Helper Calculator

The calculator has three modes. Select the mode that matches your calculation need:

📊 Mode 1: What is X% of Y?

  1. Select “What is X% of Y?” from the Mode dropdown
  2. Enter the Percentage (X) — e.g., 15 for 15%
  3. Enter the Number (Y) — e.g., 200
  4. Result: X% of Y (e.g., 15% of 200 = 30)

📈 Mode 2: X is what % of Y?

  1. Select “X is what % of Y?” from the Mode dropdown
  2. Enter the Part (X) — e.g., 30
  3. Enter the Whole (Y) — e.g., 200
  4. Result: X is (percentage)% of Y (e.g., 30 is 15% of 200)

📉 Mode 3: Increase/Decrease Y by X%

  1. Select “Increase/Decrease Y by X%” from the Mode dropdown
  2. Enter the Percentage (X) — e.g., 15 for 15%
  3. Enter the Base Number (Y) — e.g., 200
  4. Result: Shows both increased value and decreased value (e.g., 200 +15% = 230, 200 -15% = 170)

How Percentage Calculations Work (Formulas)

What is X% of Y? = (X ÷ 100) × Y
X is what % of Y? = (X ÷ Y) × 100
Increase Y by X% = Y × (1 + X ÷ 100)
Decrease Y by X% = Y × (1 — X ÷ 100)

Real Examples

Example 1 — What is 15% of 200?

  • Mode: “What is X% of Y?”
  • X = 15, Y = 200
  • Result: 30 (15% of 200 = 30)

Example 2 — 30 is what % of 200?

  • Mode: “X is what % of Y?”
  • X = 30, Y = 200
  • Result: 15% (30 is 15% of 200)

Example 3 — Increase 200 by 15% and decrease 200 by 15%

  • Mode: “Increase/Decrease Y by X%”
  • X = 15, Y = 200
  • Increased: 230 (200 + 15% = 230)
  • Decreased: 170 (200 — 15% = 170)

Why Use This Percentage Helper Calculator?

  • ✅ 3-in-1 Tool — Covers all common percentage calculations
  • ✅ Simple & Fast — No complicated formulas to remember
  • ✅ Increase & Decrease Together — See both results at once in Mode 3
  • ✅ Free & Unlimited — No signup required
  • ✅ Mobile Friendly — Responsive design for phones, tablets, and desktops

Frequently Asked Questions

How do I calculate a percentage of a number?

Formula: (Percentage ÷ 100) × Number
Example: 20% of 150 = (20 ÷ 100) × 150 = 30
Use Mode 1: What is X% of Y?

How do I find what percentage one number is of another?

Formula: (Part ÷ Whole) × 100
Example: 45 out of 150 = (45 ÷ 150) × 100 = 30%
Use Mode 2: X is what % of Y?

How do I calculate percentage increase or decrease?

Formula:
Increase: Number × (1 + Percentage ÷ 100)
Decrease: Number × (1 — Percentage ÷ 100)
Example: 200 increased by 15% = 200 × 1.15 = 230
Example: 200 decreased by 15% = 200 × 0.85 = 170
Use Mode 3: Increase/Decrease Y by X%

What’s the difference between percentage point and percent change?

Percentage point is absolute difference between two percentages (5% to 10% = +5 percentage points).
Percent change is relative change (5% to 10% = +100% increase).
This calculator shows percent change, not percentage points.

How do I calculate percentage discount?

Formula: Discounted Price = Original Price × (1 — Discount% ÷ 100)
Example: $200 item with 15% off = $200 × 0.85 = $170
Use Mode 3 and look at the decreased value result.

How do I calculate percentage markup?

Formula: Marked-up Price = Cost × (1 + Markup% ÷ 100)
Example: $100 cost with 50% markup = $100 × 1.50 = $150
Use Mode 3 and look at the increased value result.

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Disclaimer: This percentage helper calculator provides accurate results for standard percentage calculations. Results depend on correct input values. For financial or legal calculations, verify independently.