Concrete pad calculator
Estimate concrete for one or more small equipment pads, such as an AC condenser, generator or hot tub base.
Concrete pad calculator
Estimate concrete for one or more small equipment pads, such as an AC condenser, generator or hot tub base.
Enter your pad dimensions to see the concrete estimate.
Concrete needed
Project summary
How it works
These are volume estimates for planning. Actual concrete requirements depend on form dimensions, subgrade and waste.
Concrete pad calculator
Built for ordering more than one at a time
An equipment pad is usually small, but a job rarely needs just one: a multi-unit AC install or a row of mailbox pads means pouring several identical pads. This calculator multiplies one pad volume by a quantity, so the bag count and cost reflect the whole job, not one pad you then have to multiply yourself.
Common pad sizes are a starting point, not a rule
A typical residential AC condenser pad runs around 3 by 3 feet, a generator pad more like 4 by 6 feet depending on the unit, and a hot tub base needs to match the tub footprint plus a working margin. Always check the manufacturer specification for your specific equipment before pouring; pad size affects both stability and any required clearances.
Frequently asked questions
What size concrete pad do I need for an AC unit?
Most residential outdoor AC condensers sit on a pad around 3 by 3 feet, a few inches larger than the unit's base on each side. Check your specific unit's manufacturer specification, since larger commercial or multi-zone systems need a bigger pad.
How much concrete do I need for a generator pad?
A typical home standby generator pad is about 4 by 6 feet at 4 inches thick, which needs roughly 8 cubic feet of concrete, under a third of a cubic yard. Larger generators need a larger pad; check the manufacturer's installation manual for the required footprint before pouring.
How big should a hot tub concrete pad be?
Most hot tubs need a pad 8 by 8 feet or slightly larger than the tub footprint. A 6 inch thick reinforced slab is typical. The calculator lets you enter your hot tub dimensions and thickness to get the exact volume.
How thick should an AC unit concrete pad be?
A 4 inch thick pad is standard for most residential air conditioning condensers. The pad should extend 6 inches beyond the unit on all sides. The calculator shows the volume for any pad size and thickness.
Do I need rebar in a concrete pad?
Wire mesh or rebar is recommended for pads over 4 inches thick or those supporting heavy loads. The mesh helps control cracking. The calculator focuses on concrete volume, and you can add reinforcement requirements separately.
How much does a concrete pad cost?
Costs depend on size, thickness and your location. A typical 4 inch pad costs 6 to 8 dollars per square foot. The calculator gives you the square footage and volume so you can price materials and get contractor quotes.
Can I pour a concrete pad in winter?
Concrete can be poured in cold weather if proper precautions are taken, including heated enclosures and insulated blankets. The concrete must be protected from freezing for the first 48 hours. The calculator works year round, but discuss winter pours with your concrete supplier.
How long does a concrete pad take to cure?
You can walk on a pad after 24 to 48 hours. It reaches 70 percent strength in 7 days and full strength in 28 days. Keep the surface moist during the first week to reduce cracking. The calculator gives you the volume, and your supplier advises on curing for your climate.