Patio Concrete Estimator

Concrete Patio Calculator

Estimate a patio from square feet or dimensions, then move beyond yardage into bag count, ready-mix material cost, backyard access, drainage slope, finish scope, and quote checks before you approve a patio bid.

12x12 answer

1.96 yd3 with 10% waste, or 88 common 80 lb bags.

20x20 trigger

5.43 yd3 with waste, usually a ready-mix or placement quote.

Quote scope

Check base, slope, finish, access, joints, cleanup, and exclusions.

Enter Patio Size

Save this estimate or download a PDF report

The PDF report uses the current calculated result. Save the estimate first when you want to reuse the inputs later.

Results

Live estimate

Concrete Volume

1.9556 yd³

52.8 ft³ / 1.4951 m³

Bags Needed

88 bags

Rounded up to whole bags

Estimated Cost

$440.00

Based on bag price

Waste Factor

10%

Included in total volume

Concrete estimate in yards

Your 1.9556 yd3 estimate is about 88 bags after waste. Use the yard number to choose the buying path before you order.

Bags vs ready-mix comparison zone

This is the range where bagged concrete can look cheaper but delivery, short-load fees, helper availability, and placement speed can change the better option.

Check bag yield Compare delivery Review the quote

Next quote checks

Use this volume to compare ready-mix delivery, bagged concrete, delivery fees, short-load charges, and quote gaps before ordering.

Price the pour Compare bags vs ready-mix Check bag coverage Review quote gaps Compare contractor bids Save local costs

Patio buying decision in one screen

This patio may still be bag-friendly, but check the total weight, mixing pace, backyard access, and local delivery minimum before choosing.

Concrete volume

1.96 yd3

Selected bag count

Ready-mix screen

$448

This patio needs about 1.96 yd3 including waste, or 88 bags at the selected yield. At an example price of $165 per yd3 plus a $125 delivery or short-load fee, the material screen is about $448, or about $3.11 per sq ft before installed labor and scope.

Compare bags Price material Review quote

Patio scope plan

Turn patio yards into a quote-ready backyard plan

This result is a Site scope check needed with a scope score of 60/100. Use it to check the patio items that usually change the real installed price after the concrete math is already correct.

Patio area

144 sq ft

Thickness

4 in

Buying pressure

Bags versus ready-mix check

Patio next step

Confirm base depth, slope away from the house, access path, finish type, control joints, cleanup, and exclusions before treating the calculator result as an approved budget.

Build a shopping list Check truck access Normalize contractor bids

Missing patio scope before approval

Subgrade compaction, gravel base depth, drainage, and vapor barrier.
Inside-form dimensions, form bracing, thickened edges, and turndowns.
Control joint layout, saw-cut timing, finish type, curing, and cleanup.
Crew pace, truck access, chute reach, pump, buggy, or wheelbarrow distance.
Slope away from structures, drainage path, and exposed-edge finish.

Patio quote questions to ask

Does the quote include excavation, gravel base, compaction, forms, and form removal?
Are reinforcement, vapor barrier, control joints, curing, cleanup, and haul-off separated?
Does the concrete line match the calculator volume, waste factor, PSI, slump, and delivery window?
Are access limits, wheelbarrow distance, pump or buggy needs, and waiting time priced?
Are finish texture, drainage slope, steps, drains, and backyard access included?

Patio slope and drainage

Use the patio slope calculator before forms are set

Answer first: concrete patio slope is calculated as total fall across the drainage run. Slope usually has little effect on the yardage result, but it changes form elevations, drainage direction, door thresholds, grading, finish checks, and the written scope a contractor should include.

Slope formula

total fall = patio drainage run x fall per foot

Example: a 12 ft run at 1/8 in per ft needs 1.5 in of total fall from the high edge to the low edge.

What slope changes

Treat slope as a form, threshold, and water-routing decision. Keep the concrete quantity here, then ask where water exits and whether grading, drains, or restoration are separate line items.

Read slope guide Price drainage scope Review quote scope

Patio fall by drainage run
Drainage run	1/8 in per ft	3/16 in per ft	1/4 in per ft
8 ft	1.0 in fall	1.5 in fall	2.0 in fall
10 ft	1.25 in fall	1.875 in fall	2.5 in fall
12 ft	1.5 in fall	2.25 in fall	3.0 in fall
16 ft	2.0 in fall	3.0 in fall	4.0 in fall
20 ft	2.5 in fall	3.75 in fall	5.0 in fall

These are planning comparisons, not a design approval. Confirm slope, accessibility, drainage outlet, surface finish, and local requirements with a qualified professional.

Common Patio Size Answers

Patio size	With waste	80 lb bags	Ready-mix screen
10 ft x 10 ft patioSmall seating pad at 4 inches thick with 10% waste.	1.36 yd3	62	$349
12 ft x 12 ft patioCommon backyard patio at 4 inches thick with 10% waste.	1.96 yd3	88	$448
16 ft x 20 ft patioLarge seating area where ready-mix usually needs a quote.	4.35 yd3	196	$842
20 ft x 20 ft patioLarge patio that should be priced as delivery or contractor work.	5.43 yd3	245	$1021

Patio Formula

Square feet first

patio area = length x widtharea = 12 x 12 = 144.00 sq ft

Concrete volume

cubic yards = square feet x thickness in / 12 / 27final volume = 48.0000 x (1 + 10%/100)

Split L-shaped or curved patios into rectangles, calculate each section, then add waste after the sections are totaled. Estimate step pads, grill pads, fire-pit extensions, and walkway connectors separately.

Patio quote normalizer

Compare patio scope before you compare patio price

A patio estimate should not stop at concrete volume. Base prep, slope, access, finish, joints, and cleanup often explain why a material-only number and an installed bid feel far apart.

Scope	Check	Why
Base and grade	Excavation, gravel depth, compaction, slope away from structures.	A correct yardage number can still fail if water or settlement is ignored.
Finish and joints	Broom, smooth, stamped, stained, exposed, control joints, sealer.	Finish scope changes labor and warranty more than concrete volume.
Backyard access	Truck chute reach, wheelbarrow route, buggy, pump, lawn protection.	Patio placement can become a logistics job before it is a material job.
Quote comparison	Material-only cost, installed cost per sq ft, pavers comparison.	Cheap material math should not be compared directly with a full installed bid.

Patio planning pages

Keep the patio calculator connected to the buying decision

Review a patio quote

Concrete patio extension calculatorEstimate a new patio strip or add-on separately, then check tie-ins, drainage, access, and finish matching.Concrete pool deck cost calculatorCalculate deck area around a pool, then check drainage, coping, wet-surface finish, access, and replacement scope.Concrete slab calculatorStart with the base yardage before you split the patio into finish and access checks.Ready-mix vs bags calculatorCompare bag count, delivery minimums, and the point where truck delivery wins.Concrete delivery cost calculatorCheck billable yards, short-load fees, wait time, and written delivered totals.Concrete quote reviewerNormalize patio bids against the same scope before you compare price.

Frequently Asked Questions

How much concrete do I need for a 12x12 patio?

A 12 ft by 12 ft patio at 4 inches thick needs about 1.78 cubic yards before waste. With 10% waste, plan about 1.96 cubic yards, or 88 bags at a yield of 0.60 cubic feet per 80 lb bag.

How many bags of concrete are needed for a 20x20 patio?

A 20 ft by 20 ft patio at 4 inches thick needs about 5.43 cubic yards with 10% waste. That is about 245 common 80 lb bags, so ready-mix, buggy, pump, or contractor placement should be checked before buying bags.

What thickness should I use for a concrete patio?

Four inches is a common planning starting point for a simple residential patio on a prepared base. Hot tubs, outdoor kitchens, weak soil, thickened edges, structural work, or local code can require a different design.

Does a patio calculator include gravel base and drainage?

No. This calculator estimates concrete material. Gravel base, excavation, compaction, drainage slope, isolation joints, finish, cleanup, and labor should be checked as separate quote lines.

How do I use this as a concrete patio slope calculator?

Use the patio drainage run, then multiply it by the planned fall per foot. For example, 12 ft at 1/8 in per ft is 1.5 in of total fall. Slope rarely changes the yardage estimate much, but it changes form elevations, door thresholds, grading, and quote scope.

When should I compare a concrete patio with pavers?

Compare pavers when design, modular repair, drainage, or base correction matters. Use the same patio square feet, access path, base scope, demolition, and cleanup assumptions before judging the cheaper quote.

Disclaimer: This calculator is for concrete material planning only. Patio thickness, base, drainage, reinforcement, finish, code, permits, and structural needs can change the real job. Confirm structural and local requirements with a qualified contractor or engineer.