Percentage Calculator

Calculate percentages instantly — from discounts and tips to percentage change and markup. All calculations happen directly in your browser with no data collected or stored.

Percentage Calculator – SynetrixTools

📊 Result

🔢 Enter values below and click Calculate to see the result.

Calculator Type

What is __% of __?

Percentage (%)

Value

__ is what percent of __?

Part

Whole

Percentage change from __ to __

Original Value

New Value

__ is __% of what number?

Resulting Value

Percentage (%)

Example: If 45 is 15% of a number, this finds the original number (300). Useful for finding the pre-tax price, original total before a fee, etc.

Original price __ with __% off

Original Price

Discount (%)

Sales Tax (optional)

Quick Presets

Bill of __ with __% tip split __ way(s)

Bill Amount

Tip Percentage

Split Between

Quick Tip

Cost __ with __% markup

Cost / Buy Price

Markup (%)

Compare margin % and markup % side-by-side for cost __ and sell price __

Cost Price

Selling Price

Enter cost and selling price to see both metrics computed from the same numbers — useful for understanding why they differ.

Enter one "percentage,value" pair per line to calculate X% of Y for many rows at once, then export the results as a CSV file.

Batch Input (percentage,value per line)

Preview

%	Value	Result

📐 Formula Reference

Basic Percentage

Result = (Percentage ÷ 100) × Value

What Percent

% = (Part ÷ Whole) × 100

Percentage Change

% Change = ((New − Old) ÷ Old) × 100

Reverse Percentage

Original = Result ÷ (Percentage ÷ 100)

Discount

Sale Price = Price × (1 − Discount%/100)

Markup vs Margin

Markup% = (Profit ÷ Cost) × 100
Margin% = (Profit ÷ Sell Price) × 100

💡 Quick Tips

✅To find 10% of any number, simply move the decimal point one place to the left.
✅Percentage change and percentage difference are not the same — change has a direction (increase/decrease).
✅Markup is calculated on cost; margin is calculated on selling price. They are different metrics.
✅A 50% discount followed by a 50% increase does NOT return to the original price.
✅Standard restaurant tip: 15% for adequate service, 18–20% for good, 25%+ for exceptional.
✅Use Reverse % when you know the result but need to find the original number it came from.

❓ Frequently Asked Questions

What is a percentage? ▼

A percentage is a way of expressing a number as a fraction of 100. The word "percent" comes from the Latin per centum, meaning "by the hundred." For example, 45% means 45 out of every 100, or equivalently 0.45 as a decimal. Percentages are used everywhere — from grades and discounts to interest rates and statistics.

What is the difference between percentage change and percentage difference? ▼

Percentage change measures how much a value has increased or decreased relative to its original value — it has a direction (positive = increase, negative = decrease). Percentage difference compares two values without implying one is the "original" — it uses the average of both as the base. Use percentage change when tracking growth over time; use percentage difference when comparing two independent values.

What is the difference between markup and margin? ▼

Markup is the percentage added to the cost price to arrive at the selling price (based on cost). Margin (or gross margin) is the profit expressed as a percentage of the selling price. For example, a product that costs $50 and sells for $75 has a 50% markup but only a 33.3% margin. Retailers typically think in margin; manufacturers often think in markup. Use the Margin vs Markup tab above to compare both from the same numbers.

How do I calculate a percentage increase? ▼

Use the % Change tab above. The formula is: ((New Value − Original Value) ÷ Original Value) × 100. A positive result means an increase; a negative result means a decrease. For example, going from 80 to 100 is a 25% increase: ((100 − 80) ÷ 80) × 100 = 25%.

How is tip calculated? ▼

Tip is calculated as a percentage of the pre-tax bill amount. Multiply the bill by the tip percentage divided by 100 to get the tip amount, then add it to the bill for the total. When splitting, divide the total (bill + tip) by the number of people. Our Tip calculator handles all of this automatically, including per-person breakdowns.

What is reverse percentage? ▼

Reverse percentage finds the original number when you already know the result and the percentage applied. For example, if $45 is 15% of an unknown amount, the original amount is $45 ÷ 0.15 = $300. This is useful for finding a pre-discount price, a pre-tax subtotal, or an original total before a fee was deducted.

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