Calculory Guides and Tutorials
Learn the concepts behind the calculations. Step by step guides for maths, business, and financial topics with worked examples. Each guide links directly to the calculators you need.
All Guides
20 articlesHow to Calculate Percentage Increase
Learn the exact math behind growth. Master the percentage increase formula, avoid common pitfalls with original bases, and see worked examples for salaries and finance.
Read guideUnderstanding Profit Margins: Gross, Operating, and Net
Master the three levels of profitability. Learn how to calculate gross, operating, and net margins to optimize your business pricing and cost structure.
Read guideSales Tax Across US States: A 2026 Guide
Navigate the complex patchwork of US consumption tax. Learn about "NOMAD" states with no sales tax, understand economic nexus for businesses, and see how combined local rates affect your bottom line.
Read guideSimple vs. Compound Interest: The Magic of Growth
Unlock the secret to wealth building. Learn why Albert Einstein called compound interest the "eighth wonder of the world" and how math transforms small savings into large fortunes.
Read guideBreak-Even Analysis: The Profitability Threshold
Find the exact volume your startup needs to stop losing money. Master the break-even formula, understand unit economics, and learn to lower your business risk.
Read guideUnderstanding ROI: Measuring Investment returns
The universal language of profit. Learn how to calculate ROI, interpret positive and negative results, and use the metric to compare stocks, real estate, and marketing spend.
Read guideRatio vs Proportion: Difference and Formulas
Master the fundamental differences between ratios and proportions. Learn to use cross-multiplication for scaling recipes, currency, and map distances.
Read guideHow to Calculate Mean, Median, and Mode
Learn the formulas for mean, median, and mode with worked examples, and discover when to use each measure of central tendency.
Read guideHow to Calculate Standard Deviation and Variance
Master the formulas for variance and standard deviation. Learn how to measure data spread with worked examples, step-by-step calculations, and the Empirical Rule.
Read guideA Guide to Rounding Rules and Significant Figures
Master the mathematical rules of numerical rounding, learn the difference between standard and Bankers rounding, and understand how significant figures represent precision.
Read guideSignificant Figures Cheat Sheet: All Sig Fig Rules with Examples
A complete sig figs cheat sheet covering the 5 counting rules, the multiplication and division rule, the addition and subtraction rule, scientific notation, and the special logarithm rule for pH, all with worked examples and a quick reference table for common numbers.
Read guideVisualizing Function Transformations
Master the rules of shifts, stretches, and reflections. Learn how mathematical modifications inside and outside a function change its position and shape on the coordinate plane.
Read guideHow to Graph Linear Inequalities
Master the step-by-step process of graphing linear inequalities, from boundary lines to shading regions, and learn how to visualize complex solution sets.
Read guidePercentage Decrease vs. Percentage Difference
Master the two most important tools for relative comparison. Learn when to track value changes over time and how to compare independent data points without bias.
Read guideHow to Calculate Discounts: A Consumer & Business Guide
Master the math behind sales and inventory clearance. Learn to reverse-calculate original prices, find discount percentages, and understand retail markdown strategies.
Read guideUnderstanding Fractions, Decimals, and Percentages: The Complete Conversion Guide
Fractions, decimals, and percentages are three ways to express the same "parts of a whole." Master the conversion math between them with our guide, including baseline benchmarks and mental calculation shortcuts.
Read guideUnderstanding 3D Graphing in Multivariable Calculus: A Visual Guide
Move beyond the flat plane. Learn how 3D graphing visualizes multivariable surfaces, partial derivatives, and optimization peaks for advanced calculus and engineering.
Read guideUnderstanding Clinical Scoring Systems: qSOFA, BMI, and Beyond
Explore the math and logic behind clinical scoring systems like BMI and qSOFA. Learn how these standardized tools help clinicians assess risk and optimize patient outcomes.
Read guideMastering Body Composition: BMI, Lean Body Mass, and BSA Explained
Go beyond the scale. Understand the science of body composition, from BMI screening to precise Lean Body Mass and Body Surface Area calculations used in clinical medicine.
Read guidePediatric Dosage and Growth: The Critical Math of Childhood Health
Children are not just "small adults." Learn the precision math of pediatric care, from weight-based mg/kg dosing standards to mid-parental height prediction and corrected age for preemies.
Read guideMaths Guides
How to Calculate Percentage Increase
Learn the exact math behind growth. Master the percentage increase formula, avoid common pitfalls with original bases, and see worked examples for salaries and finance.
Simple vs. Compound Interest: The Magic of Growth
Unlock the secret to wealth building. Learn why Albert Einstein called compound interest the "eighth wonder of the world" and how math transforms small savings into large fortunes.
Ratio vs Proportion: Difference and Formulas
Master the fundamental differences between ratios and proportions. Learn to use cross-multiplication for scaling recipes, currency, and map distances.
How to Calculate Mean, Median, and Mode
Learn the formulas for mean, median, and mode with worked examples, and discover when to use each measure of central tendency.
How to Calculate Standard Deviation and Variance
Master the formulas for variance and standard deviation. Learn how to measure data spread with worked examples, step-by-step calculations, and the Empirical Rule.
A Guide to Rounding Rules and Significant Figures
Master the mathematical rules of numerical rounding, learn the difference between standard and Bankers rounding, and understand how significant figures represent precision.
Significant Figures Cheat Sheet: All Sig Fig Rules with Examples
A complete sig figs cheat sheet covering the 5 counting rules, the multiplication and division rule, the addition and subtraction rule, scientific notation, and the special logarithm rule for pH, all with worked examples and a quick reference table for common numbers.
Visualizing Function Transformations
Master the rules of shifts, stretches, and reflections. Learn how mathematical modifications inside and outside a function change its position and shape on the coordinate plane.
How to Graph Linear Inequalities
Master the step-by-step process of graphing linear inequalities, from boundary lines to shading regions, and learn how to visualize complex solution sets.
Percentage Decrease vs. Percentage Difference
Master the two most important tools for relative comparison. Learn when to track value changes over time and how to compare independent data points without bias.
Understanding Fractions, Decimals, and Percentages: The Complete Conversion Guide
Fractions, decimals, and percentages are three ways to express the same "parts of a whole." Master the conversion math between them with our guide, including baseline benchmarks and mental calculation shortcuts.
Understanding 3D Graphing in Multivariable Calculus: A Visual Guide
Move beyond the flat plane. Learn how 3D graphing visualizes multivariable surfaces, partial derivatives, and optimization peaks for advanced calculus and engineering.
Business Guides
Understanding Profit Margins: Gross, Operating, and Net
Master the three levels of profitability. Learn how to calculate gross, operating, and net margins to optimize your business pricing and cost structure.
Break-Even Analysis: The Profitability Threshold
Find the exact volume your startup needs to stop losing money. Master the break-even formula, understand unit economics, and learn to lower your business risk.
Understanding ROI: Measuring Investment returns
The universal language of profit. Learn how to calculate ROI, interpret positive and negative results, and use the metric to compare stocks, real estate, and marketing spend.
How to Calculate Discounts: A Consumer & Business Guide
Master the math behind sales and inventory clearance. Learn to reverse-calculate original prices, find discount percentages, and understand retail markdown strategies.