Find the right calculator.
Choose a category or browse the full library. Each tool is designed with clear units, beginner-friendly presets, and optional advanced settings.
Project cost estimators
For remodeling budgets, use the project cost estimator section. It estimates planning ranges for bathrooms, basements, decks, painting, flooring, kitchens, roofs, tile showers, and drywall repairs.
Power & Backup
5 calculators
Home Generator Size
Estimate the generator size needed for essential home backup loads during a power outage.
Open calculator → Power & BackupCamping & RV Generator
Estimate generator wattage for RV, camping, cabin, and outdoor power needs.
Open calculator → Power & BackupPower Station Runtime
Estimate how long a portable power station can run common devices.
Open calculator → Power & BackupBattery Runtime
Estimate battery runtime from watt-hours, load, and efficiency.
Open calculator → Power & BackupExtension Cord Voltage Drop
Estimate extension cord voltage drop from one-way cord length, amps, voltage, and AWG wire gauge.
Open calculator →Towing & Trailers
2 calculators
Home & Basement
10 calculators
Dehumidifier Size
Estimate dehumidifier capacity for basements, crawlspaces, and damp rooms from room dimensions and dampness level.
Open calculator → Home & BasementGarage Heater BTU
Estimate heater BTU needs for a garage, shop, or workspace.
Open calculator → Home & BasementSump Pump Size
Estimate sump pump flow requirement based on water inflow and lift height.
Open calculator → Home & BasementWater Softener Size
Estimate water softener grain capacity from household size and water hardness.
Open calculator → Home & BasementMini Split BTU
Estimate mini split BTU size from room dimensions, ceiling height, and room conditions.
Open calculator → Home & BasementAquarium Volume
Estimate aquarium volume from inside length, width, and water height.
Open calculator → Home & BasementFirewood Cords
Estimate full cords of stacked firewood from pile dimensions.
Open calculator → Home & BasementInsulation Calculator
Estimate insulation packages from area dimensions, package coverage, and waste allowance.
Open calculator → Home & BasementWall Assembly R-Value
Estimate whole-wall R-value including wall dimensions, cavity insulation, wood studs, drywall, sheathing, and continuous foam insulation.
Open calculator → Home & BasementBathroom Fan CFM
Estimate bathroom exhaust fan CFM from room size and air-change target.
Open calculator →Workshop & Tools
3 calculators
Air Compressor CFM
Estimate air compressor CFM needed for common air tools.
Open calculator → Workshop & ToolsPressure Washer Time
Estimate cleaning time from surface dimensions, pressure washer cleaning rate, and setup time.
Open calculator → Workshop & ToolsDust Collector CFM
Estimate dust collector airflow needs for common woodworking machines.
Open calculator →Materials & Projects
17 calculators
Concrete Bags
Estimate how many concrete bags you need from slab length, width, thickness, bag yield, and waste allowance.
Open calculator → Materials & ProjectsGravel Calculator
Estimate gravel volume and tonnage from length, width, and depth.
Open calculator → Materials & ProjectsPaint Calculator
Estimate paint needed from room dimensions, coats, coverage, openings, and overage.
Open calculator → Materials & ProjectsMulch Calculator
Estimate mulch volume from bed length, width, and depth.
Open calculator → Materials & ProjectsTopsoil Calculator
Estimate topsoil volume from area and depth.
Open calculator → Materials & ProjectsTile Calculator
Estimate tile quantity from project dimensions, tile size, and waste percentage.
Open calculator → Materials & ProjectsFlooring Calculator
Estimate flooring boxes from room dimensions, waste, and box coverage.
Open calculator → Materials & ProjectsFence Materials
Estimate fence posts, sections, and rail length from total fence length and spacing.
Open calculator → Materials & ProjectsDeck Boards
Estimate deck board count from deck size, board width, gap, length, and waste.
Open calculator → Materials & ProjectsDrywall Sheets
Estimate drywall sheets from surface dimensions, sheet size, and waste allowance.
Open calculator → Materials & ProjectsPaver Base
Estimate compacted gravel base and bedding sand for patios and walkways.
Open calculator → Materials & ProjectsShingle Bundles
Estimate roofing shingle bundles from building footprint, roof pitch, overhang, bundle coverage, and waste allowance.
Open calculator → Materials & ProjectsCaulk Tubes
Estimate caulk tubes from joint length, joint width, joint depth, and tube size.
Open calculator → Materials & ProjectsBoard Feet
Calculate board feet from board thickness, width, length, and quantity.
Open calculator → Materials & ProjectsStud Count
Estimate the number of wall studs needed based on wall length, stud spacing, corners, and openings.
Open calculator → Materials & ProjectsStair Stringer
Estimate stair riser count, actual riser height, tread count, and horizontal run.
Open calculator → Materials & ProjectsRoofing Underlayment
Estimate roofing underlayment rolls from building footprint, roof pitch, roll coverage, overlap, and waste.
Open calculator →Geometry Basics
9 calculators
Square Footage
Calculate square footage or square meters from length and width, with optional waste allowance.
Open calculator → Geometry BasicsRectangle Area
Find the area of a rectangle from length and width, with imperial and metric support.
Open calculator → Geometry BasicsTriangle Area
Calculate triangle area from base and height, with imperial and metric units.
Open calculator → Geometry BasicsRight Triangle
Calculate hypotenuse, area, perimeter, and angles from the two legs of a right triangle.
Open calculator → Geometry BasicsPythagorean Theorem
Find the diagonal side of a right triangle from two square sides.
Open calculator → Geometry BasicsCircle Area
Calculate circle area, circumference, and diameter from radius.
Open calculator → Geometry BasicsTrapezoid Area
Calculate trapezoid area from the two parallel bases and height.
Open calculator → Geometry BasicsCylinder Volume
Calculate cylinder volume from radius and height, with cubic feet, cubic meters, gallons, and liters.
Open calculator → Geometry BasicsRoof Pitch
Calculate roof pitch, slope angle, and slope factor from rise and run.
Open calculator →