Figuro Blog
Longer explainers on the math and formulas behind our calculators — for when a quick result isn't quite enough context.
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How to Use an MTG Calculator to Estimate Your Monthly Mortgage Payment
A step-by-step walkthrough of Figuro's mortgage calculator: which inputs matter, how PITI works, and three real scenarios worth running before you talk to a lender.
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Most Useful Millimeter to Inches Conversions Every DIYer Should Know
The mm-to-inches formula, fractional conversions, worked examples across four trades, a quick-reference table, and rounding rules that match real shop conditions.
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VAT vs Sales Tax: What's the Actual Difference?
How VAT and US sales tax actually differ — collection points, why VAT prices already include the tax, and what it means for online sellers.
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How Macro Splits Actually Work (And When to Adjust Them)
How protein, fat, and carb targets are actually calculated from your calorie goal, and when a generic macro split is worth adjusting.
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HEX, RGB, and HSL: Which Color Format Should You Use?
What HEX, RGB, and HSL color formats actually represent, and which one to reach for depending on the task.
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How Much House Can I Afford? A Simple Rule-Based Guide
The 28/36 and 3–5x income rules lenders use to estimate an affordable home price, with a worked example.
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How to Create a Budget: The 50/30/20 Method Explained
A simple three-bucket budgeting framework based on your take-home pay, with a worked example and common pitfalls.
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Debt Consolidation Explained: How It Works and When It Helps
The main consolidation methods, the break-even math, and when consolidating debt doesn't actually save money.
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Mortgage Refinancing Explained: When It's Worth It
The break-even calculation for refinance closing costs, and the hidden cost of resetting your amortization clock.
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How Retirement Savings Calculators Work (And Why Starting Early Matters)
How retirement calculators project your nest egg, the future value formula behind them, and why starting even a few years earlier changes the outcome.
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How Is BMI Calculated? A Complete Guide to Body Mass Index
What BMI actually measures, the exact formula behind it, how the standard categories are defined, and where BMI falls short as a health indicator.
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Compound Interest Explained: How Your Money Grows Over Time
The difference between simple and compound interest, why compounding frequency matters more than people expect, and a worked example you can follow by hand.
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How Mortgage Payments Are Calculated (And Why They're Mostly Interest at First)
The amortization formula behind every fixed-rate mortgage payment, and why your early payments barely touch the principal.
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How Auto Loan Payments Are Calculated (And How to Cut the Total Interest)
The auto loan payment formula, why early payments are mostly interest, and which factors actually reduce your total interest cost.
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Gross Pay vs Net Pay: How Salary Calculators Actually Work
The real difference between gross and net pay, how to convert between annual, monthly, weekly and hourly rates, and why job offers can be hard to compare.
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Body Fat Percentage Explained: What the US Navy Method Actually Measures
How the US Navy circumference method estimates body fat percentage, typical healthy ranges by sex, and why it differs from BMI.
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How Your Due Date Is Calculated (And Why It's Rarely Exact)
How the standard 40-week due date formula works, why it starts from your last period instead of conception, and why so few babies arrive on the exact date.
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Standard Deviation Explained: What It Actually Measures, in Plain English
A plain-language explanation of standard deviation, the step-by-step calculation, and the difference between population and sample standard deviation.
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How GPA Is Calculated: Weighted vs Unweighted, Explained
The GPA formula explained step by step, the difference between weighted and unweighted GPA, and how cumulative GPA changes over time.
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How Percentages Work: Percentage Change, Percentage Of, and Common Mistakes
Finding a percentage of a number, percentage change, percentage points vs percent, and how to reverse-calculate an original value.
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How Age Calculators Work (And Why Leap Years Complicate the Math)
How age is actually calculated from a birth date, why leap years affect day-based calculations, and the special case of a February 29 birthday.
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Ideal Weight Formulas Explained: Devine, Robinson, Miller, and Hamwi Compared
The four most common ideal weight formulas explained and compared, why they produce different results, and what they leave out.
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How Date Calculators Work: Counting Days Between Two Dates Correctly
Why calendar math is trickier than it looks: inclusive vs exclusive day counting, leap years, and converting days to weeks, months, and years.
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How to Simplify Fractions: The GCD Method Explained
How to simplify any fraction using the greatest common divisor, the fast Euclidean algorithm, and how to add, subtract, multiply and divide fractions.
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Password Entropy Explained: What Actually Makes a Password Strong
What password entropy actually measures, why length matters more than complexity, and practical takeaways for generating genuinely strong passwords.
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How Personal Loan Payments Are Calculated (Rate vs APR Explained)
The personal loan payment formula, the real difference between interest rate and APR, and why unsecured loans carry higher rates.
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How Calorie Calculators Work: BMR, TDEE, and Setting a Realistic Target
How BMR and TDEE are calculated using the Mifflin-St Jeor equation, how activity level factors in, and why calorie targets are estimates.
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How Unit Conversion Works (And Why Metric-to-Imperial Is Never Round)
How conversion factors work, common length and weight conversions, and why converting between metric and imperial rarely produces clean numbers.
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How Income Tax Brackets Actually Work (Marginal vs Effective Rate)
Why moving into a higher tax bracket doesn't tax all your income at that rate, and the difference between marginal and effective tax rate.
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How Sales Tax Is Calculated (And How to Reverse a Total Back to Pre-Tax Price)
The sales tax formula, how to correctly work backward from a total price, and why sales tax rates vary so much by location.
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What Is TDEE and How Is It Calculated?
How TDEE is built from BMR and an activity multiplier using the Mifflin-St Jeor formula, and how to use it to lose, maintain, or gain weight.
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How Credit Card Payoff Is Calculated (And Why Minimum Payments Cost So Much)
How credit card interest compounds daily, the math behind payoff time, and why paying only the minimum can take years and double your total cost.
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How the Quadratic Formula Works (Step by Step, With a Worked Example)
The quadratic formula explained step by step: where it comes from, how the discriminant works, and a full worked example.
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What Is a 1-Rep Max? How It's Calculated Without Actually Lifting It
What one-rep max (1RM) means, why it's rarely tested directly, and the Epley and Brzycki formulas used to estimate it safely.
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How Unit Conversion Handles Cooking Measurements (And Why Cups Aren't Reliable)
Why cooking conversions between cups, grams, and ounces aren't exact, the difference between weight and volume, and reliable conversion factors.
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How Days-From/Until Calculators Work (And Why the Count Can Look Off by One)
How days-from and days-until calculations work, why inclusive vs exclusive counting causes off-by-one confusion, and how leap years factor in.
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