One place. Every calculation.
935 free calculators for money, maths, health, science, business and everyday life. Every result comes with its formula and a worked example.
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A–Z listMoney & finance
Business & marketing
Marketing analytics
- Customer Acquisition Cost
- Customer Lifetime Value
- LTV to CAC Ratio
- Break-even ROAS
- Google Ads Budget
- Cost Per Lead
Math & science
Algebra, geometry & advanced math
- Polynomial Roots
- Cubic Equation
- Quartic Equation
- Polynomial Long Division
- Synthetic Division
- Complex Number Addition
Health & fitness
Everyday & conversions
Industry & trades
Construction
- Concrete
- Brick Quantity
- Cement Bags for Concrete
- Sand Quantity for Mortar
- Wall Plastering Quantity
- Steel Rebar Weight
Manufacturing & packaging
- Corrugated Box Board Area
- Carton Board Weight
- Carton Production Cost
- Corrugated Box Volume
- Packaging Dimensional Weight
- Die Cutting Waste
Textile & apparel
- Fabric Consumption per Garment
- Garment Costing
- Fabric GSM
- Fabric Width Conversion
- Yarn Count Ne to Tex Converter
- Yarn Count Denier to Tex Converter
Agriculture
- Seed Rate
- Plant Population
- Plant Spacing
- Fertiliser NPK
- Fertiliser Application Rate
- Drip Irrigation Discharge
Energy & environment
- Solar PV System Sizing
- Solar Payback
- Solar Self-Consumption
- Solar Inverter Sizing
- Battery Backup Runtime
- Battery State of Charge
Technology & cloud
How every calculator is checked
Our methodThe formula is written down
Each page states the exact formula, its variables and its assumptions, with sources for rules set by an authority, such as tax rates.
It is tested against known answers
The calculation code must reproduce independently derived reference values before a calculator can be published.
You can check the result
A worked example walks through every step, and the numbers in it are recomputed by the live calculator in our tests.
Calculators run in your browser: the numbers you type into them are not sent to our servers.