Home Improvement Calculators
Work out exactly how much concrete, gravel, decking, roofing, drywall, paint and more your project needs, with waste allowances, the formulas and worked examples. Free, no signup.
Popular project calculators
All tools →Concrete Calculator
Free concrete calculator for slabs, footings, columns, and stairs. Get cubic yards and cubic meters plus 40, 60, and 80 lb bag counts with 10% waste.
Gravel Calculator
Free gravel calculator for driveways, paths, and landscaping. Get cubic yards and tons of stone for rectangular, circular, or triangular areas, plus cost.
Paver Calculator
Paver calculator: count pavers for a rectangular or round patio, plus gravel base and bedding sand in cubic yards and tons.
Deck Calculator
Deck calculator: estimate deck boards, joists and screws from your deck size, board width, gap, board length and joist spacing.
Roofing Calculator
Free roofing calculator that turns roof size and pitch into shingle bundles, underlayment rolls, ridge caps, drip edge, and nails, plus a cost estimate.
Drywall Calculator
Drywall calculator: find how many 4x8, 4x10 or 4x12 sheets you need for walls and ceilings, plus joint compound, tape and screws.
Paint Calculator
Free paint calculator: estimate how many gallons or quarts of paint you need for walls and ceilings, minus doors and windows, for any number of coats.
Flooring Calculator
Flooring calculator: add up one or more rooms, include 10% or 15% waste, and see how many boxes of laminate, vinyl plank or hardwood to buy.
Mulch Calculator
Free mulch calculator for rectangle, circle, or triangle beds. Enter area and depth to get cubic yards and 2 cu ft bags needed, with an optional cost.
Fence Calculator
Fence calculator: estimate posts, rails, pickets and bags of concrete for a wood fence from its length, post spacing, height and gates.
Stair Calculator
Free stair calculator that finds riser height, tread depth, number of steps, stringer length, and stair angle from your total rise, with code checks.
Insulation Calculator
Insulation calculator for attics and walls: find blown-in depth and bags or batt bags for your target R-value, with DOE attic R-value recommendations.
Browse by category
Home & Construction Calculators
- Concrete Calculator
- BTU Calculator
- Square Footage Calculator
- Stair Calculator
- Roofing Calculator
- Tile Calculator
- Mulch Calculator
- Gravel Calculator
- Board Foot Calculator
- Deck Calculator
- Drywall Calculator
- Fence Calculator
- Flooring Calculator
- Insulation Calculator
- Paint Calculator
- Paver Calculator
- Retaining Wall Calculator
- Wallpaper Calculator
- Rebar Calculator
- Roof Pitch Calculator
- Deck Footing Calculator
- Siding Calculator
- Concrete Block Calculator
- Baseboard & Trim Calculator
Free Developer & Text Tools
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- Word Counter
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- Text Diff Checker
- Base64 Encoder/Decoder
- URL Encoder/Decoder
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- UUID Generator
- Hash Generator
- Password Generator
- Regex Tester
- Color Converter
- Unix Timestamp Converter
- HTML Formatter
- CSS Formatter
- JavaScript Formatter
- SQL Formatter
- Markdown Preview
- IP Subnet Calculator
- Bandwidth Calculator
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Formulas shown
Guides under each tool explain the formula and walk through examples, so you can check the result.
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Latest guides
All guides →How Many Bags of Concrete Do I Need?
One cubic yard takes 45 bags of 80 lb concrete, 60 of 60 lb or 90 of 40 lb. Bag counts for slabs, walkways, post holes and footings, with the formula.
How Thick Should a Concrete Slab Be?
Most patios, walkways and shed pads are 4 inches thick; driveways are usually 5 to 6. Thickness, gravel base and rebar or mesh for each type of slab.
Bagged Concrete vs Ready-Mix: Which Is Cheaper?
Bags usually win below about 1 cubic yard (45 bags of 80 lb); ready-mix usually wins above it. How to find your own break-even point, fees included.