Guides
Learn the math behind everyday decisions
In-depth guides, explanations, and how-tos
Plain-English guides to the math behind everyday decisions — how mortgage payments really work, what BMI does and doesn't tell you, how to scale a recipe, and why percentage tricks work. Every article is written to be read in a few minutes, with worked examples, and pairs with a free calculator or interactive guide so you can run your own numbers immediately.
How Mortgage Payments Actually Work (With Real Numbers)
Apr 1
How to Calculate Car Payment
Apr 18
How to Calculate Break-Even Point
Apr 19
How to Calculate Salary
Apr 16
Markup vs Margin — What's the Difference?
Apr 6
How to Calculate ROI on Investment
Apr 10
How to Calculate Loan Interest
Mar 30
How to Calculate Retirement Savings
Apr 17
How to Calculate Sales Commission
Apr 5
Personal Loan vs Mortgage Guide
Mar 28
Compound Interest Guide
Mar 18
How to Calculate Discount
Apr 15
How to Calculate Body Fat Percentage
Apr 16
How to Calculate Ideal Weight
Aug 16
How to Calculate BMI for Kids
Aug 16
BMI: What It Measures, What It Misses, and When to Ignore It
Mar 25
How Many Calories Does Exercise Burn?
Mar 23
TDEE and Calorie Guide
Aug 16
How Much Protein Do You Need Per Day?
Mar 21
How to Calculate Macros for Cutting & Bulking
Mar 22
How to Calculate Lean Body Mass
Mar 27
What Is BMR and How to Calculate It?
Mar 19
How to Estimate Blood Alcohol Content
Aug 16
How Much Weight Should You Gain During Pregnancy?
Aug 16
How to Calculate Ovulation and Fertile Window
Aug 16
How Much Water Should You Drink Daily?
Aug 16
Sleep Cycle Calculator: How Sleep Works
Mar 24
How to Calculate Your Exact Age
Apr 9
How to Calculate Gas Cost for a Trip
Apr 11
How to Calculate Unit Price and Find the Best Deal
Apr 2
Tip Calculator Guide: How Much to Tip
Aug 16
How to Calculate GPA
Apr 15
How to Convert Shoe Sizes Between US, UK & EU
Apr 4
How to Scale Recipes and Convert Cooking Measurements
Apr 1
How to Calculate Dog Age in Human Years
Mar 31
How to Calculate Work Hours on a Time Card
Mar 29
Temperature Conversion Guide
Apr 20
How to Calculate Combinations and Permutations
Apr 20
Percentage Calculation Guide
Aug 16
How to Use a Fraction Calculator
Apr 14
Exponent Rules Explained
Apr 12
Probability Explained Simply
Apr 13
How to Calculate Area
Apr 17
Pythagorean Theorem Explained
Apr 18
Standard Deviation Explained
Mar 22
Square Root Explained
Apr 4
Unit Conversion Complete Guide
Apr 8