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 to Pay Off Your Mortgage Faster (With Real Numbers)
Nov 4
How to Calculate Overtime Pay
Nov 4
Home Equity Loan vs HELOC — How They Work
Nov 4
How to Fill Out a W-4 (2026, Step by Step)
Nov 4
How to Calculate Markup (and Margin)
Nov 2
How to Value Junk Silver: The Actual Math, Step by Step
Nov 1
Why Gold Coins Cost More Than Bars — and When It's Worth Paying
Nov 1
How to Track a Gold and Silver Stack (Fine Weight, Explained)
Nov 1
How to Calculate Roth Conversion Taxes (With Real Numbers)
Oct 30
How Much Do I Need to Retire? (The Real Math, With Numbers)
Oct 30
How Much of Your Social Security Is Taxable? (With Real Numbers)
Oct 30
How to Calculate Retirement Savings
Oct 8
How Mortgage Payments Actually Work (With Real Numbers)
Oct 8
Compound Interest Guide
Oct 8
How to Calculate Break-Even Point
Apr 19
How to Calculate Car Payment
Apr 18
How to Calculate Salary
Apr 16
How to Calculate ROI on Investment
Apr 10
Markup vs Margin — What's the Difference?
Apr 6
How to Calculate Sales Commission
Apr 5
How to Calculate Loan Interest
Mar 30
Personal Loan vs Mortgage Guide
Mar 28
TDEE and Calorie Guide
Oct 8
How Much Weight Should You Gain During Pregnancy?
Oct 8
BMI: What It Measures, What It Misses, and When to Ignore It
Oct 8
How to Calculate Ovulation and Fertile Window
Oct 8
How Much Water Should You Drink Daily?
Oct 8
How to Calculate Ideal Weight
Aug 16
How to Calculate BMI for Kids
Aug 16
How to Estimate Blood Alcohol Content
Aug 16
How to Calculate Body Fat Percentage
Apr 16
How to Calculate Lean Body Mass
Mar 27
Sleep Cycle Calculator: How Sleep Works
Mar 24
How Many Calories Does Exercise Burn?
Mar 23
How to Calculate Macros for Cutting & Bulking
Mar 22
How Much Protein Do You Need Per Day?
Mar 21
What Is BMR and How to Calculate It?
Mar 19
How to Calculate Gas Cost for a Trip
Apr 11
How to Calculate How Much Paint You Need
Apr 7
How to Calculate TV and Monitor Screen Size
Apr 6
How to Calculate How Much Concrete You Need
Apr 3
How to Calculate Electricity Cost
Mar 30
How Many Hours Between Two Times? (With Examples)
Nov 4
How to Calculate Working Days Between Two Dates
Nov 4
How to Calculate Discount
Oct 8
Tip Calculator Guide: How Much to Tip
Oct 8
How to Calculate Dog Age in Human Years
Oct 8
How to Calculate GPA
Apr 15
How to Calculate Your Exact Age
Apr 9
How to Convert Shoe Sizes Between US, UK & EU
Apr 4
How to Calculate Unit Price and Find the Best Deal
Apr 2
How to Scale Recipes and Convert Cooking Measurements
Apr 1
How to Calculate Work Hours on a Time Card
Mar 29
How to Calculate Days Between Dates (With Examples)
Nov 4
Percentage Calculation Guide
Oct 8
How to Calculate Combinations and Permutations
Oct 4
Temperature Conversion Guide
Apr 20
Pythagorean Theorem Explained
Apr 18
How to Calculate Area
Apr 17
How to Use a Fraction Calculator
Apr 14
Probability Explained Simply
Apr 13
Exponent Rules Explained
Apr 12
Unit Conversion Complete Guide
Apr 8
Square Root Explained
Apr 4
Standard Deviation Explained
Mar 22