Every calculation, one place.
Calculate anything. Understand everything.
Explore 120 calculators and 187 long-form guides across finance, maths, science, health, construction and everyday planning. See formulas, worked examples and limitations, with AI-assisted explanations where available.
Specialized Calculators
No account required
Flagship Calculators
Top daily-utilized tools for mortgages, 2D graphing, fraction arithmetic, construction, and taxes.
Mortgage & Loan Amortization Schedule Calculator
Calculate monthly mortgage payments, complete loan amortization schedule, total principal vs interest ratio, and early payoff acceleration.
2D Scientific Graphing Calculator & Function Plotter
Interactive Cartesian coordinate plotter. Graph multiple mathematical curves, inspect roots, intercepts, trigonometric functions, polynomials, and asymptotes.
Fraction Calculator with Step-by-Step Solution
Add, subtract, multiply, and divide fractions and mixed numbers with step-by-step LCD determination, cross-multiplication, and GCD simplification.
Feet and Inches Construction & Carpentry Calculator
Add, subtract, and multiply architectural dimensions in feet, inches, and fractions (down to 1/16th) with instant metric millimeter conversion.
Concrete Calculator (Slabs, Footings & Columns)
Calculate concrete volume in cubic yards, cubic feet, and cubic metres, plus required 60lb, 80lb, and 50kg premix bags with customizable wastage margin.
South Africa PAYE Tax Calculator
Estimate South African monthly PAYE for the 2026/27 or 2025/26 tax year, including age-based rebates, retirement contributions, medical scheme fees tax credits and UIF.
Body Fat Percentage Calculator (US Navy Method)
Measure body fat percentage, lean muscle mass, and fat mass using circumference measurements standardized by the US Navy.
Compound Interest & Investment Calculator
Forecast investment growth with compound frequency, regular monthly deposits, and inflation adjustment.
Macronutrient Splitter & TDEE Calculator
Calculate daily calorie targets and exact gram breakdowns for Protein, Carbohydrates, and Fats based on fitness goals (Cutting, Maintenance, Bulking).
Explore by Discipline
Tailored tools with region-aware currency, measurement units, and statutory tax rules.
Original Guides & Learning Resources
Rigorous breakdowns of statutory tables, mathematical models, and financial strategies.
How to Calculate Percentages: A Complete Practical Guide
Learn how percentages express proportions, how to find a percentage of a value, and how to reverse or compare percentage changes.
Percentage Increase and Decrease Explained
Calculate relative change without confusing the difference with the percentage change.
Fractions Explained: Simplifying, Adding, Multiplying and Dividing
Build a reliable method for working with fractions and interpreting numerator and denominator.
Built on mathematical transparency.
Unlike closed-box calculator sites, Calcendo documents every statutory table version, mathematical equation, and limitation upfront. If you discover a rate change or edge case, report it and our editorial team inspects and updates it promptly.