All calculators
77 calculators in six categories. Each one shows its formula, assumptions and a worked example.
Home Projects
Concrete
- Concrete Bag CalculatorConvert a known concrete volume into 40, 50, 60 and 80 lb bags.
- Concrete Footing CalculatorConcrete for continuous (strip) footings and curbs by linear foot.
- Concrete Post Hole & Column CalculatorConcrete bags for fence post holes, deck piers and round columns (sonotubes).
- Concrete Slab CalculatorCubic yards, bags and cost for slabs, patios, driveways, sidewalks and pads.
- Concrete Steps CalculatorConcrete volume for a solid set of poured steps with an optional top landing.
- Cubic Yard CalculatorCubic yards, cubic feet and cubic meters for one or more areas at a depth, with weight in tons and truckloads.
- Rebar Calculator for SlabsRebar grid for a concrete slab: bars each way, linear feet with lap splices, stock bars to buy, weight and chairs.
Masonry
Deck
- Deck Board CalculatorDeck boards, linear feet and deck screws for a rectangular deck.
- Deck Footing & Post CalculatorNumber of deck posts and footings, and concrete for round footings.
- Deck Joist CalculatorNumber of joists, joist hangers and rim board length for a deck frame.
- Deck Railing & Baluster CalculatorRailing posts and balusters with the 4-inch sphere rule.
- Stair & Stringer CalculatorRisers, riser height, treads, total run and stringer length from total rise.
Fence
Roofing
- Roof Pitch CalculatorRoof pitch, angle, slope factor and percent grade from rise and run.
- Roofing Calculator (Squares, Shingles & Drip Edge)Roof area, squares, shingle bundles, underlayment, ridge cap and drip edge from footprint and pitch.
- Rafter Length Calculator (Common Rafters)Common rafter length with ridge reduction and overhang, plumb cut angle, birdsmouth size and rafter count.
Paint
Flooring
- Carpet CalculatorCarpet off a 12, 13.5 or 15 ft roll for each room, in linear feet and square yards.
- Flooring CalculatorSquare feet and boxes of hardwood, laminate or vinyl plank for one or more rooms.
- Tile CalculatorNumber of floor or wall tiles and boxes, accounting for grout joints.
- Square Footage CalculatorTotal square feet, square yards and square meters for rooms and areas of any common shape, with optional cost.
- Epoxy Resin CalculatorHow much epoxy to mix for a table top, river table, round pour or floor coating, split into resin and hardener, with the number of pour layers.
Insulation
Home Energy
HVAC
- BTU to kW & Tons ConverterConvert heating and cooling capacity between BTU/h, watts, kW and tons.
- CFM & Air Changes per Hour CalculatorConvert between room airflow (CFM) and air changes per hour (ACH).
- Duct Size Calculator (Velocity Method)Round duct diameter and rectangular duct size for an airflow and target velocity.
- Heating Load & Furnace Size EstimateDesign heating load from walls, windows, ceiling and air leakage; furnace input size from AFUE.
- AC BTU Calculator (Room Cooling)Room air conditioner or mini-split size in BTU/h using the ENERGY STAR room sizing method.
Energy bills
- Appliance Energy Cost CalculatorkWh and cost per day, month and year for any appliance.
- Water Heater Energy Cost CalculatorYearly energy and cost to heat water for electric, heat pump and gas water heaters.
- Propane Tank Run Time CalculatorHow many hours and days a propane cylinder or tank lasts for your grill, heater, furnace or generator.
Solar
- Solar Battery Size CalculatorBattery capacity (kWh) for backup days, depth of discharge and efficiency.
- Solar Payback & Savings CalculatorNet cost, payback year and lifetime savings for a solar system with your own rates and incentives.
- Solar Panel & System Size CalculatorSolar system size (kW), number of panels, roof area and estimated yearly production.
Plumbing
Pipe flow
- Pipe Flow & Water Velocity CalculatorWater velocity from flow rate and pipe size, or flow rate from velocity.
- Water Pipe Size Calculator (Velocity Method)Smallest copper, PEX or PVC pipe that keeps water velocity under a limit.
- Pipe Volume CalculatorGallons of water held in a length of pipe, and its weight.
- Pipe Pressure Drop Calculator (Hazen-Williams)Friction pressure loss in a water pipe plus elevation change.
Water heaters
Electrical
Power
Wiring
- Extension Cord Voltage Drop CalculatorVoltage at the tool for an extension cord gauge, length and load.
- Voltage Drop CalculatorVoltage drop and percent drop for copper or aluminum conductors by AWG size and length.
- Wire Size Calculator (Voltage Drop)Smallest conductor that keeps voltage drop under your limit.
- Conduit Fill CalculatorPercent fill of EMT, PVC, rigid or flexible conduit with THHN/THWN-2 wires, checked against NEC Chapter 9 limits.
Vehicle & Towing
Towing
Fuel
Garden & Outdoor
Mulch & soil
Gravel & landscaping
- Gravel, Sand & Stone CalculatorCubic yards and tons of gravel, crushed stone, sand or rock from area and depth.
- Paver Patio CalculatorPavers, gravel base and bedding sand for a paver patio or walkway.
- Asphalt Calculator (Tons for a Driveway)Tons and cubic yards of hot-mix asphalt for a driveway or path, with cost per ton and the aggregate base below.
- Retaining Wall Block CalculatorBlocks, cap units, base gravel, drainage gravel and drain pipe for a segmental block retaining wall.
- Sod & Grass Seed CalculatorSod rolls and pallets for one or more lawn areas, plus pounds of grass seed at your seeding rate.