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Concrete Slab Calculator

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Home, Trade & Construction

Concrete Slab Calculator

Pour size first
Order volume1.63 yd³Updates as you type · 1.246 m³ cross-check
1.481Measured yd³1.246Order m³74Bags rounded up$0.00Ready-mix check
Measured 40 ft³ plus 10% overage = 44 ft³. Bag count uses 0.6 ft³/bag.
Bag and ready-mix basisKeep ordering proof visible
Live result1.63 yd³ order1.481 yd³ measured · 1.246 m³ order · 74 bag(s) rounded up.
Formula used

Thickness in feet = thickness inches ÷ 12. Base volume in cubic feet = length feet × width feet × thickness feet. Cubic yards = cubic feet ÷ 27. Cubic metres = cubic feet × 0.028316846592. Order volume = base volume × (1 + waste percent ÷ 100). Estimated bags = order cubic feet ÷ bag yield.

This is the method behind the answer, so the result can be checked rather than simply trusted.

Live math canvas

Your numbers, formula and explanation together

Concrete Slab Calculator: 1.6296 yd³. 1.4815 yd³ base · 1.1327 m³ · 73.33 bags

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Thickness in feet = thickness inches ÷ 12. Base volume in cubic feet = length feet × width feet × thickness feet. Cubic yards = cubic feet ÷ 27. Cubic metres = cubic feet × 0.028316846592. Order volume = base volume × (1 + waste percent ÷ 100). Estimated bags = order cubic feet ÷ bag yield.
  1. Apply the formulaThickness in feet = thickness inches ÷ 12. Base volume in cubic feet = length feet × width feet × thickness feet. Cubic yards = cubic feet ÷ 27. Cubic metres = cubic feet × 0.028316846592. Order volume = base volume × (1 + waste percent ÷ 100). Estimated bags = order cubic feet ÷ bag yield.1.6296 yd³1.4815 yd³ base · 1.1327 m³ · 73.33 bags

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Slab length
12 ft
Enter the planned slab length in feet.
Slab width
10 ft
Enter the planned slab width in feet.
Slab thickness
4 in
Enter the slab depth or thickness in inches.
Waste / overage
10 %
Allowance for grade variation, spillage, form bulge and ordering safety margin.
Bag yield
0.6 cu ft per bag
Optional bag yield for bagged concrete. Many 80 lb bags are about 0.6 cu ft; check your product label.
Optional ready-mix price
0 per cu yd
Optional price per cubic yard for a quick quote note before delivery fees, short-load fees or tax.

Resulting answer

1.6296 yd³

1.4815 yd³ base · 1.1327 m³ · 73.33 bags

Answer
1.6296 yd³
Live support
1.4815 yd³ base · 1.1327 m³ · 73.33 bags

Assumptions used

What this answer assumes

Best for patios, shed pads, small slabs, classroom volume worksheets and quote notes where the geometry, overage and bag or ready-mix basis should stay visible.

  • The slab is treated as a rectangular prism with even thickness across the full length and width.
  • Thickness is entered in inches and converted to feet before volume is calculated.
  • Waste or overage is kept separate from the measured geometric volume.
  • Bag count is a planning estimate based on the entered bag yield; always check the product label and round up for whole bags.
  • Concrete ordering can depend on subgrade, reinforcement, slump, delivery limits, pump access, minimum loads, weather and local practice.
  • For structural slabs, driveways, footings, permits or code work, use a qualified professional and the project drawings/specifications.

Master’s Tip

How to use the result well

Master’s Tip: do not hide overage inside the dimensions. Print the measured slab volume first, then the overage line, so the pour record shows what came from geometry and what came from job-site judgement.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Slab length
12 ft
Enter the planned slab length in feet.
Slab width
10 ft
Enter the planned slab width in feet.
Slab thickness
4 in
Enter the slab depth or thickness in inches.
Waste / overage
10 %
Allowance for grade variation, spillage, form bulge and ordering safety margin.

Visual grid

This result measures part of the space you live in

Length, area, volume and material estimates are grid problems too: measure the space, account for edges and allowances, then turn the pattern into a number you can use.

Micro-timehours, minutes, shiftsHuman scaledays, weeks, projectsMacro-timemonths, years, calendars
Measured output1.6296 yd³

Space calculations turn a real surface, room, run or volume into cells, edges and allowances that can be quoted, ordered or checked.

CalculationTime

Concrete Slab Calculation Report

Report date:

1.6296 yd³1.4815 yd³ base · 1.1327 m³ · 73.33 bags

Inputs

Slab length
12 ft
Slab width
10 ft
Slab thickness
4 in
Waste / overage
10 %
Bag yield
0.6 cu ft per bag
Optional ready-mix price
0 per cu yd

Method

Thickness in feet = thickness inches ÷ 12. Base volume in cubic feet = length feet × width feet × thickness feet. Cubic yards = cubic feet ÷ 27. Cubic metres = cubic feet × 0.028316846592. Order volume = base volume × (1 + waste percent ÷ 100). Estimated bags = order cubic feet ÷ bag yield.

  1. For a 12 ft by 10 ft slab at 4 inches thick, thickness = 4 ÷ 12 = 0.3333 ft. Base volume = 12 × 10 × 0.3333 = 40 cu ft. Cubic yards = 40 ÷ 27 = 1.4815 cu yd. With 10% overage, order volume = 1.6296 cu yd, or about 73.33 bags at 0.6 cu ft per bag before rounding up.

Assumptions

  • The slab is treated as a rectangular prism with even thickness across the full length and width.
  • Thickness is entered in inches and converted to feet before volume is calculated.
  • Waste or overage is kept separate from the measured geometric volume.
  • Bag count is a planning estimate based on the entered bag yield; always check the product label and round up for whole bags.

Notes

Use this space on the printed report for client, supplier, classroom, job-location, measurement, quote or approval notes.

Source: https://www.calculationtime.com/calculators/concrete-slab-calculator

This report shows the calculation inputs, formula, assumptions and result for review. It is not legal, payroll, tax, engineering, financial or academic advice unless a qualified professional confirms the applicable rules.