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Concrete Unit Converter

Convert length, area, volume, weight, and temperature between imperial and metric units with quick reference tables for every common concrete measurement.

Use this free concrete unit converter to switch between inches and feet, cubic feet and cubic yards, pounds and kilograms, and imperial and metric units for any concrete measurement. Whether you are converting a slab thickness from inches to feet before entering it in a calculator, checking a ready-mix order in cubic meters, or converting a bag weight from pounds to kilograms, enter your value and get the result instantly with no formula memorization required.

Five Conversion Categories - Length, area, volume, weight, and temperature - all the unit types needed for concrete planning in one tool.

Bidirectional Real-Time Conversion - Type in either field and the other updates instantly. Switch direction without clearing your input.

Quick Reference Tables - Pre-calculated conversion tables for the most common concrete measurements, with no input required.

Imperial and Metric - Covers standard US construction units like inches, feet, yards, pounds, and Fahrenheit plus metric equivalents.

Copy and Share - Copy any converted value to the clipboard or share a link to the converter with your current value and unit pair.

Converter Section

Convert concrete units instantly

Select a conversion category below, enter a value in either field, and get the result instantly. For volume calculations, use the concrete calculator or the slab calculator. To convert a finished volume estimate into bag counts, use the concrete bag calculator.

ft³ ↔ yd³ | in³ ↔ ft³ | yd³ ↔ m³

From

Cubic feet. Intermediate unit produced by most hand calculations.

To

Cubic yards. Primary ready-mix ordering unit in the United States.

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How to Convert Concrete Measurements

Most concrete calculation errors start with a unit mismatch - entering thickness in inches when the formula expects feet, or confusing cubic feet with cubic yards when placing a ready-mix order. This section covers the five most important unit conversions in concrete work, with the formulas, worked examples, and the context you need to avoid the most common mistakes.

Core Concrete Conversion Formulas

LENGTH
inches to feet:    divide by 12
feet to inches:    multiply by 12
feet to meters:    multiply by 0.3048
meters to feet:    multiply by 3.2808

AREA
ft² to m²:         multiply by 0.0929
m² to ft²:         multiply by 10.764
in² to ft²:        divide by 144

VOLUME
ft³ to yd³:        divide by 27
yd³ to ft³:        multiply by 27
yd³ to m³:         multiply by 0.7646
m³ to yd³:         multiply by 1.3080
in³ to ft³:        divide by 1,728

WEIGHT
lb to kg:          multiply by 0.4536
kg to lb:          multiply by 2.2046

TEMPERATURE
°F to °C:          (°F - 32) × 5 ÷ 9
°C to °F:          °C × 9 ÷ 5 + 32

Step-by-Step Guide

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Step 1 - Convert Thickness from Inches to Feet

The most common unit error in concrete calculations is entering slab thickness in inches when the volume formula requires feet. To convert inches to feet, divide by 12. A 4-inch slab is 4 ÷ 12 = 0.333 feet. A 6-inch wall is 6 ÷ 12 = 0.5 feet. All concrete volume calculators on ConcreteCalc Pro accept thickness in inches and convert automatically, but if you are doing the math by hand, this conversion is the step most likely to cause an error.

2

Step 2 - Convert Cubic Feet to Cubic Yards

Ready-mix concrete in the United States is ordered in cubic yards. Volume formulas such as length × width × thickness produce cubic feet when dimensions are in feet. To convert cubic feet to cubic yards, divide by 27 because one cubic yard is 3 ft × 3 ft × 3 ft = 27 cubic feet. For a slab that calculates to 40 cubic feet: 40 ÷ 27 = 1.48 cubic yards. This is the single most important unit conversion in concrete work.

3

Step 3 - Convert Cubic Yards to Cubic Meters

For international projects or when working with metric drawings, multiply cubic yards by 0.7646 to get cubic meters. For 1.48 cubic yards: 1.48 × 0.7646 = 1.13 m³. To convert in the other direction, multiply cubic meters by 1.308 to get cubic yards. All ConcreteCalc Pro calculators display both cubic yards and cubic meters simultaneously in the results panel, which makes this cross-check fast.

4

Step 4 - Convert Bag Weights

Standard US concrete bag sizes are 40 lb, 60 lb, 80 lb, and 90 lb. To convert to kilograms, multiply by 0.4536, so an 80 lb bag is 80 × 0.4536 = 36.3 kg. This is useful when ordering from international suppliers or comparing with metric bag sizes. Standard metric bag sizes are 20 kg, which is about 44 lb, and 25 kg, which is about 55 lb.

5

Step 5 - Convert Curing Temperatures

Concrete curing is temperature-sensitive. The standard curing temperature range in the United States is 50°F to 90°F, which is about 10°C to 32°C. To convert Fahrenheit to Celsius, subtract 32 and then multiply by 5/9. For 50°F, the result is 10°C. For cold-weather concreting, the critical threshold is 40°F or 4.4°C. Below this temperature, hydration slows significantly and concrete must be protected from freezing.

Quick Reference Conversion Tables

Use these pre-calculated conversion tables to look up common concrete measurements without entering any values. Each table covers the most frequently needed conversions for concrete planning, ordering, and field measurement.

Inches to Feet Conversion Chart

InchesFeet (decimal)Feet (fraction)Common Use
1 in0.083 ft1/12 ftRebar cover
2 in0.167 ft1/6 ftThin overlay
3 in0.250 ft1/4 ftMinimum slab thickness
3.5 in0.292 ft7/24 ftResidential patio
4 in0.333 ft1/3 ftStandard slab
5 in0.417 ft5/12 ftHeavy-duty slab
6 in0.500 ft1/2 ftWall or footing
7 in0.583 ft7/12 ftStair rise
8 in0.667 ft2/3 ftFoundation wall
9 in0.750 ft3/4 ftThick wall
10 in0.833 ft5/6 ftStair run
11 in0.917 ft11/12 ftComfort stair run
12 in1.000 ft1 ftStandard reference
18 in1.500 ft1.5 ftFooting depth
24 in2.000 ft2 ftDeep footing
36 in3.000 ft3 ftMid-climate frost line
48 in4.000 ft4 ftCold-climate frost line

Decimal feet values are inches divided by 12. Fraction values are simplified practical equivalents for layout work and field checks.

Cubic Feet to Cubic Yards Conversion Chart

Cubic FeetCubic YardsWith 10% OverageNotes
1 ft³0.037 yd³0.041 yd³Small patch
5 ft³0.185 yd³0.204 yd³Post holes
10 ft³0.370 yd³0.407 yd³Small footing
15 ft³0.556 yd³0.611 yd³Entry stoop
20 ft³0.741 yd³0.815 yd³Small slab
27 ft³1.000 yd³1.100 yd³1 cubic yard
40 ft³1.481 yd³1.630 yd³Medium slab
54 ft³2.000 yd³2.200 yd³2 cubic yards
81 ft³3.000 yd³3.300 yd³3 cubic yards
108 ft³4.000 yd³4.400 yd³4 cubic yards
135 ft³5.000 yd³5.500 yd³5 cubic yards
270 ft³10.000 yd³11.000 yd³Minimum truck load

One cubic yard equals 27 cubic feet exactly. The overage column multiplies the converted cubic-yard value by 1.1.

Cubic Yards to Cubic Meters Conversion Chart

Cubic YardsCubic MetersNotes
0.5 yd³0.382 m³Small pour
1.0 yd³0.765 m³Minimum ready-mix order
1.5 yd³1.147 m³Medium pour
2.0 yd³1.529 m³-
3.0 yd³2.294 m³-
5.0 yd³3.823 m³-
7.0 yd³5.352 m³-
10.0 yd³7.646 m³Minimum truck load
15.0 yd³11.468 m³-
20.0 yd³15.291 m³-

One cubic yard equals 0.764555 cubic meters. Values are rounded to three decimals for quick field reference.

Concrete Bag Weight Conversion Chart

US Bag SizeWeight (kg)Yield (ft³)Yield (yd³)Bags per yd³
40 lb18.1 kg0.30 ft³0.011 yd³~90 bags
50 lb (fast-set)22.7 kg0.375 ft³0.014 yd³~72 bags
60 lb27.2 kg0.45 ft³0.017 yd³~60 bags
80 lb36.3 kg0.60 ft³0.022 yd³~45 bags
90 lb40.8 kg0.675 ft³0.025 yd³~40 bags
20 kg (metric)44.1 lb0.44 ft³0.016 yd³~62 bags
25 kg (metric)55.1 lb0.55 ft³0.020 yd³~49 bags

Yield values are standard planning benchmarks for normal-weight bagged concrete. Actual yield can vary slightly by mix design and water content.

Concrete Curing Temperature Reference

°F°CConcrete Condition
20°F-6.7°CDo not pour. Concrete can freeze before it gains strength.
32°F0°CFreezing point. Cold-weather protection is required.
40°F4.4°CMinimum safe pour temperature. Insulate and monitor.
50°F10°CSlow curing. Extend the curing period.
60°F15.6°CAcceptable. Standard curing applies.
70°F21.1°CIdeal curing temperature.
75°F23.9°CIdeal curing temperature.
90°F32.2°CHot weather. Use cool water and shade forms.
100°F37.8°CHot-weather concreting measures are required.

Temperature guidance is a field reference only. Always follow the project specification and local cold-weather or hot-weather concreting procedures.

Frequently Asked Questions

These unit converter FAQs cover the most common concrete measurement conversions, including cubic feet to cubic yards, inches to feet, imperial to metric volume, and bag weight conversions. The first two answers are expanded by default.

How many cubic feet are in a cubic yard?+

There are exactly 27 cubic feet in one cubic yard. One cubic yard is a cube that measures 3 feet × 3 feet × 3 feet, which equals 27 cubic feet. To convert cubic feet to cubic yards, divide by 27. To convert cubic yards to cubic feet, multiply by 27. This is the most important unit conversion in concrete work because volume calculations produce cubic feet when dimensions are in feet, while ready-mix orders in the United States are placed in cubic yards.

How do I convert inches to feet for a concrete calculation?+

To convert inches to feet, divide by 12. Common concrete thickness conversions include 3.5 inches = 0.292 ft, 4 inches = 0.333 ft, 6 inches = 0.5 ft, and 8 inches = 0.667 ft. This conversion is needed when calculating slab, wall, or footing volume by hand with the formula length × width × thickness ÷ 27. ConcreteCalc Pro calculators accept thickness in inches and convert automatically, but if you are doing the calculation manually, dividing thickness by 12 before multiplying is the step most likely to cause an ordering error.

How do I convert cubic yards to cubic meters?+

To convert cubic yards to cubic meters, multiply by 0.7646. To convert cubic meters to cubic yards, multiply by 1.308. For example, 2.5 cubic yards × 0.7646 = 1.91 cubic meters. This conversion is needed when working with international suppliers, metric project drawings, or ready-mix prices quoted in different units. ConcreteCalc Pro calculators display results in both cubic yards and cubic meters, which makes it easier to compare imperial and metric estimates without switching tools.

How many kilograms is an 80 lb bag of concrete?+

An 80 lb bag of concrete weighs approximately 36.3 kilograms because 80 × 0.4536 = 36.3 kg. Other common conversions are 40 lb = 18.1 kg, 60 lb = 27.2 kg, and 90 lb = 40.8 kg. Standard metric bag sizes are 20 kg, which is about 44 lb, and 25 kg, which is about 55 lb. When ordering from international suppliers or comparing with metric products, use the Weight tab in the converter to convert any bag size instantly.

What is the minimum temperature to pour concrete?+

The minimum safe temperature for pouring concrete is 40°F, which is 4.4°C. Below this temperature, the hydration reaction that hardens concrete slows significantly, and below 32°F the water in the mix can freeze before the concrete sets, causing permanent damage. When air temperatures are between 40°F and 50°F, cold-weather concreting measures are required, including warm mix water, insulated forms, and a longer curing period. Do not pour concrete when temperatures are expected to drop below freezing within 24 hours without active heat and insulation.

How do I convert a concrete volume from cubic feet to bags?+

To convert cubic feet to bags, first convert cubic feet to cubic yards by dividing by 27, then divide by the yield per bag. For 80 lb bags, the working yield is about 0.022 yd³ each, so the formula is bags = (cubic feet ÷ 27) ÷ 0.022. For example, 10 cubic feet becomes 0.370 yd³, and 0.370 ÷ 0.022 is about 17 bags when you include practical ordering overage. The concrete bag calculator is faster if you want counts for all bag sizes at once.

What is the difference between a short ton and a metric ton for concrete?+

A short ton, which is used in the United States, equals 2,000 pounds or about 907 kilograms. A metric ton, also called a tonne, equals 1,000 kilograms or about 2,205 pounds. Concrete weighs roughly 150 lb per cubic foot, which is about 2,400 kg per cubic meter, so one cubic yard of concrete weighs around 4,050 lb. That is about 2 short tons or 1.84 metric tons. This matters when estimating structural loads, comparing aggregate prices, or checking truck payload capacity.

How do I convert square feet to square meters for concrete formwork?+

To convert square feet to square meters, multiply by 0.0929. To convert square meters to square feet, multiply by 10.764. For example, 200 square feet of formwork equals 200 × 0.0929 = 18.6 square meters. This conversion is useful when ordering plywood or form panels in metric sizes, or when comparing formwork costs with international contractors. The Area tab in the converter above lets you switch between square feet, square yards, square inches, and square meters instantly.

Related Tools

Put your conversions to work

Once you have your converted measurements, use these calculators to estimate concrete volume, bag counts, and project cost.

Concrete Calculator

The all-in-one concrete calculator for slabs, footings, columns, walls, and stairs. Enter your converted dimensions directly to get cubic yards, bag counts, and cost.

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Concrete Bag Calculator

Convert cubic yards or cubic feet into 40 lb, 60 lb, 80 lb, and 90 lb bag counts. The fastest way to turn a volume estimate into a hardware store shopping list.

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Concrete Cost Calculator

Estimate total material and labor cost for any concrete pour. Enter your volume in cubic yards or cubic meters to get a full cost breakdown.

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