Construction Calculators
Estimate concrete, roofing, tile, mulch, gravel, BTU requirements, electricity costs, square footage, stair dimensions, and AC sizing with free construction calculators.
Materials
View all →Concrete Calculator
Calculate how much concrete you need in cubic yards or bags for slabs, footings, and columns.
BTU Calculator
Calculate the BTU heating or cooling capacity needed for your room based on dimensions.
Roofing Calculator
Estimate roofing materials needed including shingles, underlayment, and ridge caps by area.
Tile Calculator
Calculate the number of tiles needed for floors or walls including waste allowance.
Mulch Calculator
Calculate how many bags or cubic yards of mulch you need for your garden beds.
Gravel Calculator
Calculate the amount of gravel needed in tons or cubic yards for driveways and landscaping.
Electricity Calculator
Calculate electricity costs and energy consumption for appliances and your entire home.
Area & Design
View all →Square Footage Calculator
Calculate the square footage of rooms and spaces for flooring, painting, and renovation projects.
Stair Calculator
Calculate stair dimensions including rise, run, number of steps, and stringer length.
Construction Area Calculator
Calculate the built-up area, carpet area, and super built-up area for construction projects.
AC BTU Calculator
Calculate the right air conditioner BTU size for your room based on area and conditions.
About Construction Calculators
Our construction calculators help homeowners, contractors, and DIY enthusiasts plan building projects with accurate material estimates and dimensional calculations. Every calculator includes waste factors and industry-standard formulas.
Materials calculators cover the most common construction supplies. The Concrete Calculator determines cubic yards, bag counts, and costs. Roofing, Tile, Mulch, and Gravel calculators provide quantity estimates with built-in waste allowances to prevent costly shortages and project delays.
The BTU Calculator and AC BTU Calculator serve different purposes: the general BTU calculator handles heating and cooling load calculations for entire homes, while the AC BTU calculator focuses specifically on air conditioning unit sizing for individual rooms with detailed adjustment factors for sun exposure, insulation, and occupancy.
Area and dimension tools include the Square Footage Calculator for measuring rooms and properties, the Stair Calculator for code-compliant staircase design, the Construction Area Calculator for lot and foundation measurements, and the Electricity Cost Calculator for estimating appliance and system operating costs.
Frequently Asked Questions
How much concrete do I need for a 10x10 slab?
A 10x10 foot slab at 4 inches thick requires approximately 1.23 cubic yards of concrete. With a 10% waste factor, order about 1.36 cubic yards. This translates to roughly 46 bags of 80-lb premix or 61 bags of 60-lb premix. For any slab over 1 cubic yard, ordering ready-mix delivery is typically more cost-effective and ensures proper mixing.
What size AC unit do I need for my room?
A general rule is 20 BTU per square foot. A 500 sq ft room needs roughly 10,000 BTU (about 1 ton). Adjust upward for kitchens (+4,000 BTU), heavy sun exposure (+10%), poor insulation (+20%), or extra occupants (+600 BTU each). Our AC BTU calculator accounts for all these factors automatically.
How do I calculate roofing materials?
Measure the footprint area and multiply by the roof pitch factor. Divide total square footage by 100 to get 'roofing squares.' Each square requires 3 bundles of standard shingles. Add 10-15% for waste, valleys, and starter strips. Ridge cap shingles are calculated separately based on ridge line length.
How much mulch do I need?
Mulch is calculated by area (square feet) times depth (typically 2-4 inches), converted to cubic yards or 2-cubic-foot bags. One cubic yard covers about 162 square feet at 2 inches deep, 108 square feet at 3 inches, or 81 square feet at 4 inches deep.
What is the proper stair riser height?
The International Residential Code (IRC) sets the maximum riser height at 7-3/4 inches (196.85mm) with a minimum tread depth of 10 inches (254mm). The comfort rule of thumb is that riser height plus tread depth should equal 17-18 inches. Our stair calculator automatically checks code compliance.