The CalcAsk Blog
Practical, evergreen guides on money, health, and everyday math — written to go deeper than any single calculator.
All articles
The 50/30/20 Budget Rule, Explained (With Examples)
A practical walkthrough of the popular budgeting framework, with real number examples and common pitfalls.
Money · 10 min readGross vs. Net Pay: What Actually Comes Out of Your Paycheck
A clear breakdown of what typically gets deducted and how to estimate real take-home pay.
Money · 8 min readHow Tax Brackets Actually Work
Why a raise can never reduce your take-home pay, and marginal vs. effective tax rate.
Everyday · 7 min readWhy Your "1TB" Drive Shows 931GB
Decimal vs. binary storage units, and how currency conversion works.
Health · 6 min readHow Pregnancy Due Dates Are Calculated
Naegele's rule, why it's an estimate, and how ultrasound dating differs.
Fitness · 7 min readHow to Calculate Running Pace & Predict a Race Time
Why predicting a marathon from a 5K isn't a straight-line multiplication.
Security · 7 min readWhy Password Length Beats Complexity
The entropy math behind why a longer simple password often beats a shorter complex one.
Math · 8 min readHow to Calculate Probability
Basic probability, odds vs. probability, and the AND/OR rules for combining events.
Business · 8 min readROI, Invoices & Sales Tax
Why discount always applies before tax, and the math for ROI and sales tax.
Writing · 7 min readWord Count, Reading Time & Text Case
How these tools actually work, and the difference between title case and sentence case.
Science · 8 min readDensity, Force, Ohm's Law & Molarity
Four fundamental formulas with worked examples and the units mistakes that trip people up.
Health · 9 min readBody Fat, Ideal Weight, Protein & Water
What each formula actually measures, and why these are estimates, not diagnoses.
Math · 9 min readPercentages, Discounts, Ratios & Fractions
Why a 25% increase then a 25% decrease doesn't get you back to where you started.
How-To · 8 min readHow to Calculate Days Between Two Dates
Calendar days vs. business days vs. calendar-accurate age — three methods explained.
Math · 10 min readMean vs. Median vs. Mode vs. Standard Deviation
What each one measures, when averages lie to you, with a real worked example.
How-To · 9 min readHow Many Bricks, Tiles, or Bags of Concrete Do You Need?
A practical guide to waste allowances and the math for four common projects.
Money · 10 min readMarkup vs. Margin: What's the Difference
Why the two get confused, and the pricing mistake it causes, with conversion tables.
Money · 9 min readHow VAT Actually Works
Calculating, adding, and reclaiming VAT, with real worked examples.
Money · 9 min readHow Compound Growth Actually Works
Why starting early beats contributing more later, with real worked numbers.
Health · 8 min readBMI Explained: What It Measures and What It Doesn't
How BMI is calculated, what the categories mean, and its real limitations.
Health · 9 min readBMR vs. TDEE: What's the Difference?
Two commonly confused numbers, and which one to actually use for weight goals.
How-To · 9 min readMetric vs. Imperial: A No-Headache Conversion Guide
Exact formulas and mental shortcuts for length, weight, and temperature conversions.