Building material calculators

Q: How much concrete do I need for a slab?

Length times width times thickness in feet, divided by 27 for cubic yards. A 12 by 10 ft slab at 4 inches is about 1.5 cubic yards, roughly 74 eighty-pound bags with waste.

Q: How many bags of concrete are in a cubic yard?

About 45 eighty-pound bags, 60 sixty-pound bags, or 90 forty-pound bags per cubic yard. Each 80-lb bag yields roughly 0.6 cubic feet, and a yard is 27 cubic feet.

Q: How much gravel do I need for a driveway?

Area times depth divided by 27 for cubic yards; multiply by about 1.4 for tons. A 20 by 10 ft driveway at 3 inches deep needs roughly 1.85 cubic yards, or about 2.6 tons.

Q: How do I convert gravel tons to cubic yards?

One ton of gravel is roughly 0.7 cubic yards, because loose dry gravel weighs about 1.4 tons per cubic yard. Damp or compacted stone weighs more, so adjust the density.

Q: How much mulch do I need?

One cubic yard of mulch covers about 100 square feet at 3 inches deep, roughly 13 to 14 of the 2-cubic-foot bags.

Q: How much sand do I need under pavers?

A 1-inch sand bedding layer under 100 square feet is about 0.3 cubic yards, roughly 0.4 tons. The paver calculator also sizes the base gravel.

Q: How much paint do I need for a room?

A gallon covers about 350 to 400 square feet per coat. A 12 by 12 ft room takes about 2 gallons for two coats of wall paint, before doors and windows.

Q: How many bricks are in a square foot?

About 7 modular bricks per square foot of single-wythe wall with 3/8-inch joints, plus roughly 10 percent waste and mortar.

Q: Do the calculators include a waste factor?

Yes. Every result includes an adjustable 5 to 10 percent waste allowance, always shown, so the quantity is order-ready.

Q: Can I trust the numbers?

Every formula is checked against manufacturer bag yields, published material densities, and code references. Results are estimates; confirm against product specs and local conditions before ordering.

How much concrete
do you need?

example12 × 10 ft slab → 1.5 yd³ · 70 bags

Free calculators for concrete, gravel, lumber, tile and more — with the exact bags, tons and boxes to order. No sign-up.

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Hover a point on the house and we’ll show the exact calculators you need for it.

Room

For a room, you’ll usually need

Flooringboxes · sq ft→Paintgallons→Drywallsheets · mud→Tiletiles · boxes→

Wall

For a wall, you’ll usually need

Brickbricks · mortar→Concrete blockblocks · mortar→Concreteyd³ · bags→

Deck

For a deck, you’ll usually need

Board footboard feet→Square footagesq ft→

Garden

For a garden, you’ll usually need

Mulchyd³ · bags→Topsoilyd³ · tons→Graveltons · yd³→

Driveway

For a driveway, you’ll usually need

Graveltons · yd³→Concreteyd³ · bags→Paverpavers · base→

Patio

For a patio, you’ll usually need

Paverpavers · base→Concreteyd³ · bags→Sandtons · yd³→

3D house - hover a zone for its calculators

The full toolkit

Every calculator, drawn to scale.

14 calculators across 5 trades →

01Concrete

Concrete & masonry

S-1

Concrete Concrete block Brick

02Aggregates

Aggregates & landscaping

C-2

Gravel Sand Mulch Topsoil

03Surfaces

Surfaces & finishes

A-3

Tile Flooring Paint Drywall

04Lumber

Lumber & framing

W-1

Board foot

05Core

Core & measurement

A-1

Square footage Paver

Reviewed & verified

Every number, signed off.

Before a formula goes live it’s checked against manufacturer specs and code — by someone who’s ordered a lot of concrete the hard way.

Buy-in units

Bags, tons, boxes and gallons — the units the store sells.

Waste built in

An adjustable 5–10% factor, always shown — order-ready.

Optional cost

Editable regional rates turn any quantity into a budget.

Fast & mobile

Instant, thumb-friendly, and built to pass Core Web Vitals.

Straight answers, then the calculator that does it for your exact job.

How much concrete do I need for a slab?

Length × width × thickness in feet, divided by 27 for cubic yards. A 12 × 10 ft slab at 4 in is about 1.5 yd³ — roughly 74 × 80-lb bags with waste.
Open the concrete calculator →

How many bags of concrete are in a cubic yard?

About 45 × 80-lb, 60 × 60-lb, or 90 × 40-lb bags per cubic yard. Each 80-lb bag yields roughly 0.6 cubic feet, and a yard is 27 cubic feet.
Open the concrete calculator →

How much gravel do I need for a driveway?

Area × depth ÷ 27 for cubic yards; multiply by about 1.4 for tons. A 20 × 10 ft drive at 3 in needs roughly 1.85 yd³, or about 2.6 tons.
Open the gravel calculator →

How do I convert gravel tons to cubic yards?

One ton of gravel is roughly 0.7 cubic yards — loose, dry gravel weighs about 1.4 tons per yard. Damp or compacted stone weighs more, so the tool lets you adjust the density.
Open the gravel calculator →

How much mulch do I need?

One cubic yard covers about 100 sq ft at 3 in deep — roughly 13 to 14 of the 2-cubic-foot bags. Deeper beds and wider borders scale from there.
Open the mulch calculator →

How much sand do I need under pavers?

A 1-inch bedding layer under 100 sq ft is about 0.3 yd³ (roughly 0.4 tons). The paver calculator also sizes your base gravel.
Open the paver calculator →

How much paint do I need for a room?

A gallon covers about 350–400 sq ft per coat. A 12 × 12 ft room usually takes about 2 gallons for two coats of wall paint, before doors and windows.
Open the paint calculator →

How many bricks are in a square foot?

About 7 modular bricks per square foot of single-wythe wall (3/8-inch joints), plus roughly 10% waste and the mortar to lay them.
Open the brick calculator →

Do the calculators include a waste factor?

Yes — every result includes an adjustable 5–10% waste allowance, always shown, so the quantity is order-ready rather than a bare minimum.
Browse all calculators →

Can I trust the numbers?

Every formula is checked against manufacturer bag yields, published material densities, and code references. Results are estimates — confirm against product specs and local conditions before ordering.
Browse all calculators →

Try it right here

Estimate any material.

Pick a material, set the depth, and drag out your area — get the quantity to order, live.

Thickness

1.5yd³· 74 × 80-lb bags

Open the concrete calculator →

Or browse all 15 calculators →