Percentage Calculator Calculate tips, discounts, margins, growth rates, and more — with real-world examples and 2025 benc...

Percentage Calculator

Calculate tips, discounts, margins, growth rates, and more — with real-world examples and 2025 benchmarks.

What is X% of Y?

X is what % of Y?

% Increase/Decrease

% Difference

Percentage (%)

Of What Number?

Context Tip Sales Tax Discount Markup

Part ($)

Whole ($)

Scenario Discount Contribution Gross Margin

From ($)

To ($)

Type Growth/Decline Inflation Adjust

Value A ($)

Value B ($)

$0.00

Result

0.0%

Percentage

$0.00

Final Value

—

Change

Percentage Visualization

Percentage Formulas

What is X% of Y?**:

$$ Result = Y \times \frac{X}{100} $$

X is what % of Y?**:

$$ \% = \frac{X}{Y} \times 100\% $$

% Change**:

$$ \% = \frac{\text{New} - \text{Old}}{\text{Old}} \times 100\% $$

% Difference**:

$$ \% = \frac{|A - B|}{(A + B)/2} \times 100\% $$

Examples**:

• 18% of $85 = **$15.30**
• $45 off $120 = **37.5%** discount
• $90 → $126 = **+40%** growth
• $80 vs. $100 = **22.2%** difference

✅ Pro Tip**: Use “percentage points” for absolute changes (e.g., rate from 5% → 7% = +2 **points**, not +40%).

Percentage Red Flags

⚠️ Avoid these misleading claims:

• “Up to 50% off” anchoring** — Only 3% of items actually discounted 50%
• “50% more free!”** — 50% more = 33% off (e.g., 150g for price of 100g)
• Compounding confusion** — 10% + 10% ≠ 20% (it’s 19% on $100: $110 → $121)
• Margin vs. markup mixup** — 40% margin ≠ 40% markup (markup = 66.7% for 40% margin)

✅ Smart Math Tips**:

• **Tip shortcut**: 10% = move decimal left → double for 20%
• **Discount hack**: 25% off = ÷4; 20% off = ÷5
• **Tax included?** Divide final by 1.08 to get pre-tax price (for 8% tax)

2025 Percentage Benchmarks

Context	Strong	Moderate	Risk
Gross Margin	≥50% (SaaS)	30–50% (Retail)	<25%
Tip	20%+	15–20%	<15%
Savings Rate	≥20%	10–20%	<5%

📉 Real-World Examples**:

• Meal**: $85 × 18% = **$15.30 tip** → $100.30 total
• Sale**: $299 × 30% = **$89.70 off** → $209.30 final
• Stock**: $75 → $93 = **+24%** gain
• COGS**: $60 on $100 sale = **40% margin**, **66.7% markup

How to Use This Calculator

➡️ What is X% of Y?

“18% of $85 — how much tip?” → **$15.30**

➡️ X is what % of Y?

“$45 off $120 — what % discount?” → **37.5%**

➡️ % Increase/Decrease

“$90 → $126 — % change?” → **+40%**

➡️ % Difference

“$80 vs. $100 — difference?” → **22.2%**

Note: Uses exact percentage math. All monetary values rounded to 2 decimals. Difference uses average denominator for symmetry.