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Percentage Calculator
Guides

Guides & Tutorials

Learn everything about percentage calculations with our comprehensive guides and tutorials.

Our percentage guides cover the most common real-world calculations — from shopping discounts and restaurant tips to business profit margins and academic grades. Each guide includes step-by-step formulas, worked examples, data tables, and pro tips written by our math and finance team.

Shopping

How to Calculate Discounts: Complete Guide

Learn how to calculate discounts, sale prices, and savings with easy formulas and examples.

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Daily Life

How to Calculate Tips: Restaurant Tipping Guide

Master the art of calculating tips with our comprehensive guide for restaurants, services, and more.

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Finance

How to Calculate Sales Tax

Understanding sales tax calculations for shopping, business, and tax planning.

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Education

Percentage Increase and Decrease Explained

Learn to calculate percentage changes, growth rates, and understand increases vs decreases.

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Business

How to Calculate Profit Margin

Essential guide to profit margin calculations for business owners and entrepreneurs.

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Education

How to Calculate Grades and GPA

Convert scores to percentages, calculate weighted grades, and understand GPA calculations.

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Finance

How to Calculate Compound Interest

Learn the compound interest formula, compare it with simple interest, and use the Rule of 72 to estimate how fast your money doubles.

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Finance

How to Calculate Simple Interest

Master the simple interest formula I = P × r × t with clear examples, practical applications, and a comparison with compound interest.

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Business

How to Calculate Return on Investment (ROI)

Learn the ROI formula, annualized ROI, and real-world examples for real estate, stocks, and business investments.

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Business

How to Calculate Markup and Selling Price

Master markup calculations, understand the difference between markup and margin, and learn common markup percentages by industry.

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Business

How to Calculate Sales Commission

Learn how to calculate sales commissions, understand tiered structures, and compare common commission models across industries.

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Finance

How to Calculate Inflation and Purchasing Power

Understand inflation calculations, CPI, purchasing power changes, and the difference between real and nominal values.

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Career

How to Calculate Salary Increase and Raise

Learn how to calculate salary raises, understand cost of living adjustments, and prepare for salary negotiations with real examples.

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Science

How to Calculate Percentage Error

Learn the percentage error formula, understand absolute vs relative error, and discover acceptable error ranges for science and engineering.

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Finance

How to Calculate Mortgage Payments

Understand the mortgage payment formula, amortization schedules, and how interest rates affect your total home loan cost.

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Health

How to Calculate BMI (Body Mass Index)

Learn the BMI formula in both metric and imperial units, understand BMI categories, and know the limitations of this common health metric.

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Education

How to Calculate Percentage Difference

Understand the percentage difference formula, how it differs from percentage change, and when to use each calculation.

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Finance

How to Calculate Savings Goals

Learn formulas for monthly savings targets, emergency funds, and retirement planning with and without interest.

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Shopping

How to Calculate Unit Price for Smart Shopping

Master unit price calculations to compare products, evaluate bulk deals, and save money on groceries and everyday purchases.

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Education

Converting Between Percentages, Decimals, and Fractions

Master the conversion methods between percentages, decimals, and fractions with a common equivalents table and practice examples.

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