How much concrete do I need for a patio?

Use the formula: Volume (CY) = Length (ft) x Width (ft) x Thickness (ft) / 27 For a 4-inch thick patio, thickness in feet = 4/12 = 0.333 ft. Common examples: • 10x10 ft patio: 10 x 10 x 0.333 / 27 = 1.23 CY net, order 1.36 CY (+10%) • 12x12 ft patio: 12 x 12 x 0.333 / 27 = 1.78 CY net, order 1.96 CY • 16x20 ft patio: 16 x 20 x 0.333 / 27 = 3.95 CY net, order 4.35 CY Always add 10% for waste. For any patio over 1 CY, order ready-mix delivered by truck rather than mixing bags by hand.

How thick should a concrete patio be?

The minimum thickness for a residential concrete patio is 3.5 inches (90mm) per ACI 318, but the recommended standard is 4 inches (100mm). • 3.5 inches (90mm): Absolute minimum — only for very light foot traffic • 4 inches (100mm): Standard for most residential patios and garden paths • 5 inches (125mm): If you'll have heavy outdoor furniture, a fire pit, or a large grill • 6 inches (150mm): If any vehicle (car, riding mower, golf cart) will ever access the area Thicker concrete is significantly stronger — a 5-inch slab is about 56% stronger in bending than a 4-inch slab. Adding wire mesh or rebar is recommended regardless of thickness.

How much does a concrete patio cost?

US cost breakdown (2025 averages): • Plain broom-finished concrete: $8–$12 per square foot installed • Exposed aggregate finish: $10–$16 per square foot • Stamped concrete (decorative pattern): $15–$25 per square foot • Coloured concrete: add $2–$5 per sq ft to any of the above Example — 12 x 12 ft plain concrete patio: • 144 sq ft x $8–$12 = $1,152–$1,728 installed • Material only: ~1.96 CY x $140 = ~$274 Labour makes up the majority of the cost. Decorative options significantly increase price. Get at least 3 local quotes — pricing varies widely by region and season.

Should I use rebar or wire mesh in a patio?

Both add tensile strength that concrete lacks on its own: • Welded wire mesh (6x6 W1.4 x W1.4): The standard minimum for patios. Cheap, easy to lay, good for preventing cracks from spreading. Place at mid-depth (2 inches down for a 4-inch slab). • #3 rebar on 18-inch grid: Stronger than mesh, better for larger patios or areas with poor soil. More expensive and labour-intensive to install. For a standard 4-inch residential patio, welded wire mesh is sufficient. For patios in clay soil (which expands and contracts with moisture), rebar is recommended. Neither guarantees zero cracking — proper sub-base preparation (4 inches of compacted gravel) and control joints (cut every 8–10 feet) are equally important.

What is the difference between a concrete patio and a concrete driveway?

The main differences are thickness, strength spec, and finish: • Thickness: Patios are typically 4 inches; driveways 5–6 inches • Mix strength: Patios typically use 3,500 PSI; driveways 4,000 PSI • Finish: Patios often have decorative finishes (stamped, exposed aggregate, coloured); driveways are usually broom-finished • Reinforcement: Both benefit from wire mesh or rebar • Cost per sq ft: Patios typically cost more due to decorative options If your patio will be adjacent to the driveway and you want vehicle access, pour it at 6 inches with 4,000 PSI mix to match the driveway spec.

How long should I wait before using a new concrete patio?

Curing timeline: • 24 hours: Keep everyone off — no foot traffic • 3–5 days: Light foot traffic allowed • 7 days: Patio furniture, grills, and normal use • 28 days: Full design strength — heavy loads allowed Do not seal a new concrete patio until it has cured for at least 28 days. In hot, dry weather (above 90°F / 32°C), mist with water and cover with plastic sheeting for the first 3–5 days to slow drying and prevent surface cracking. In cold weather (below 40°F / 4°C), cover with insulating blankets for the first 48 hours.

Concrete Patio Calculator — Cubic Yards, Cost & Size Guide

The Concrete Patio Calculator tells you exactly how much concrete to order for any rectangular patio. Enter your length, width, and thickness in imperial (feet and inches) or metric (metres and millimetres), and the calculator instantly outputs volume in cubic yards and cubic feet, adds a 10% waste allowance so you nev..

PATIO DIMENSIONS

LENGTH (feet)

WIDTH (feet)

THICKNESS (inches)

CONCRETE PRICE ($/CY, optional)

US avg: $125–$165/CY ready-mix (2025)

RESULTS

VOLUME (net)

1.48 CY

= 40.0 cubic feet

WITH 10% WASTE — order this amount

1.63 CY

SURFACE AREA

120 sq ft

80 LB BAGS

READY-MIX MATERIAL COST

$228

at $140/CY + 10% waste

INSTALLED COST ESTIMATE

$960 – $2,400

$8–$20/sq ft incl. labour, forming, finishing

PATIO VISUALISER (not to scale)

PATIO SUMMARY

Surface area120 sq ft

Volume (net)40.00 cu ft

Volume (net)1.481 CY

Volume +10% waste1.630 CY

80 lb bags (+waste)74

Ready-mix cost (est.)$228

Installed cost (est.)$960 – $2,400

THICKNESS GUIDE

3.5"

Minimum code (foot traffic)

ACI minimum for residential flatwork

Standard patio

Most residential patios

Heavy outdoor furniture/spa

Hot tubs, large grills

Vehicle access

If cars will drive or park

COMMON PATIO SIZES

Small (1–2 people)8×8 ft — 100 sq ft

Medium (4–6 people)12×12 ft — 144 sq ft

Large (8+ people)16×20 ft — 320 sq ft

Pool surround8 ft border around pool

Created with❤️byeaglecalculator.com

HOW TO USE

1
Choose Imperial (feet and inches) or Metric (metres and millimetres). Use the quick preset buttons — Small patio, Medium patio, Large patio, Pool surround — to pre-fill standard dimensions instantly and get a ballpark estimate in seconds.
2
Enter your patio Length and Width. For an L-shaped or irregular patio, split it into rectangular sections, calculate each section separately, and add the volumes. The calculator handles one rectangular area at a time.
3
Select your thickness. Standard residential patios use 4 inches (100mm) for foot traffic and patio furniture. Increase to 5 inches if placing a heavy spa or outdoor kitchen. Use 6 inches if any vehicle will ever drive or park on the area.
4
Enter your local ready-mix concrete price per cubic yard (US) or cubic metre (metric) for a material cost estimate. The calculator also shows a full installed cost range covering labour, forming, and finishing — useful for comparing contractor quotes.
5
Read the results: volume in cubic yards and cubic feet, volume with 10% waste added (always order this amount), surface area, bag equivalent for small pours, ready-mix material cost, and total installed cost estimate. For patios over 1 cubic yard, always order ready-mix — it gives consistent strength and saves hours of mixing.

WORKED EXAMPLE

How much concrete for a 14 ft x 18 ft backyard patio, 4 inches thick? Step 1: Convert thickness to feet 4 inches / 12 = 0.333 ft Step 2: Calculate volume in cubic feet 14 ft x 18 ft x 0.333 ft = 83.93 cubic feet Step 3: Convert to cubic yards 83.93 / 27 = 3.11 cubic yards Step 4: Add 10% waste 3.11 x 1.10 = 3.42 CY — order 3.5 CY (round up to nearest 0.25) Step 5: Surface area 14 x 18 = 252 sq ft Step 6: Material cost at $140/CY 3.42 CY x $140 = $479 for ready-mix concrete material Step 7: Installed cost estimate 252 sq ft x $8–$12 = $2,016–$3,024 (plain broom-finished, labour + material + forming) 252 sq ft x $15–$25 = $3,780–$6,300 (stamped decorative concrete) Step 8: Bag equivalent (not recommended for this volume) 83.93 x 1.10 / 0.60 = 154 x 80lb bags — use ready-mix instead

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Last updated: April 29, 2026 · Formula verified by EagleCalculator team · Eagle-eyed accuracy for every calculation.