Why this site exists
Most home projects start with the same question: how much do I need? Buying too little means a second trip to the store or a cold joint in a concrete slab; buying too much wastes money. Our goal is simple: give you a fast, accurate estimate with no sign-up, no pop-ups and no guesswork, and explain how the number was calculated so you can trust it.
How our calculators are built
- Transparent formulas. Every calculator shows the formula it uses, so you can check the math yourself.
- Recognized references. Where standards exist we follow them: stair dimensions from the International Residential Code (IRC), wire sizes and voltage drop from the National Electrical Code (NEC) ampacity tables and conductor properties, air conditioner sizing from the ENERGY STAR room sizing chart, and pool chemistry from standard chemical conversions.
- Real product data. Bag yields, roll sizes and coverage rates are based on typical values published by manufacturers, such as about 0.60 cubic feet of concrete per 80 lb bag.
- Tested results. Each calculator is checked against hand calculations and known reference values before it is published. The example numbers and reference tables on every page are generated with the same formula as the calculator itself, so they always match.
Units
All calculators accept feet, inches, yards, meters and centimeters (and gallons, liters or cubic meters for pools), and switch between US and metric units with one click. Your preference is remembered on your device.
Privacy by design
Calculations run entirely in your browser. The numbers you type are never sent to a server or stored by us.
Limitations
Our results are estimates for planning and purchasing. Real quantities depend on site conditions, product specifications and installation methods, and building codes vary by location. Always check product labels and supplier quantities, and consult your local building department or a licensed professional for structural, electrical and safety-related work.
Our calculators
- Concrete Calculator
- Cubic Yard Calculator
- Gravel Calculator
- Sand Calculator
- Paver Calculator
- Sqft Calculator
- Tile Calculator
- Paint Calculator
- Flooring Calculator
- Drywall Calculator
- Wallpaper Calculator
- Stair Stringer Calculator
- Pool Volume Calculator
- Pool Salt Calculator
- Pool Chlorine Calculator
- Mulch Calculator
- Topsoil Calculator
- Sod Calculator
- Raised Bed Soil Calculator
- Grass Seed Calculator
- Roofing Calculator
- Siding Calculator
- Deck Calculator
- Fence Calculator
- Retaining Wall Calculator
- Rebar Calculator
- Baseboard Calculator
- Grout Calculator
- Board Foot Calculator
- Pool Shock Calculator
- Pool Alkalinity Calculator
- Pool Stabilizer Calculator
- Lawn Fertilizer Calculator
- Lawn Lime Calculator
- Firewood Cord Calculator
- Wire Size Calculator
- Voltage Drop Calculator
- BTU Calculator
- Generator Size Calculator
- Solar Panel Calculator