6 min read

How to Calculate Percentage

Learn the essential percentage formulas and choose the right method for any percentage question.

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7 min read

Percentage Formula Explained

Understand the percentage formula, its variables and the most common ways to rearrange it.

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6 min read

How to Calculate Percentage Change

Calculate increases and decreases from an original value and understand the result correctly.

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5 min read

How Discount Calculations Work

Turn a discount rate into money saved and the final price using two clear steps.

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3 min read

How to Calculate Percentage Increase

Learn the percentage increase formula with step-by-step examples. Calculate growth, raises and price increases.

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3 min read

How to Calculate Percentage Decrease

Learn the percentage decrease formula with examples. Calculate price drops, reductions and losses.

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3 min read

Percentage Change vs Percentage Difference

Understand when to use percentage change and when to use percentage difference. They are not the same.

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3 min read

Markup vs Margin: What's the Difference?

Learn the critical difference between markup and profit margin. Both use cost and price but answer different questions.

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3 min read

How to Calculate Tax on a Price

Learn how to add tax to a price and how to find the pre-tax price from a total. Step-by-step examples.

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3 min read

How to Calculate a Tip and Split the Bill

Learn how to calculate tips, split bills and figure out how much each person pays. Quick formulas for dining out.

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4 min read

How to Convert Fractions, Decimals and Percentages

Master conversions between fractions, decimals and percentages. Complete guide with all formulas and examples.

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2 min read

How to Calculate Age — Complete Guide

Learn how age is calculated from a birth date, including years, months, days, leap years and common edge cases.

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2 min read

How Age Is Calculated — Behind the Algorithm

Understand the calendar math behind age calculation: subtracting dates, handling leap years and counting total days.

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2 min read

How Many Days Have I Lived?

Learn how to count every day you have been alive, why the number surprises most people and how to find milestone days.

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2 min read

Leap Year Birthday — How Age Is Calculated for Feb 29

How age works when you were born on February 29. Learn the legal and mathematical conventions for leap day birthdays.

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