Concrete Conversion Calculator
Convert concrete units instantly cubic yards to feet, feet to meters, PSI to MPa, bags to yards, and weight conversions.
Concrete Conversion Calculator: Convert Any Concrete Unit Instantly
Concrete work spans two measurement worlds. Ready-mix suppliers in the US quote in cubic yards. International drawings arrive in millimeters and cubic meters. Structural specifications list strength in PSI. European standards use MPa. Bags are measured in pounds. Delivery trucks carry tons. Temperature affects curing in both Fahrenheit and Celsius. At some point in every concrete project, you need to convert between these systems accurately, quickly, and without a conversion error that cascades into a wrong order quantity, a failed structural calculation, or a misread specification.
This concrete conversion calculator covers every unit conversion you will encounter in residential and commercial concrete work. Volume conversions between cubic yards, cubic feet, cubic meters, cubic inches, and liters. Length conversions between inches, feet, yards, meters, and centimeters. Weight conversions between pounds, US tons, metric tons, and kilograms. Strength conversions between PSI, MPa, and N/mm². Bag-to-volume conversions for all standard bag sizes. Area conversions between square feet, square yards, and square meters. And temperature conversions for curing condition planning.
Every conversion is presented with the formula, a worked example, and a comprehensive reference table so you can verify results instantly. Whether you are converting a single dimension or translating an entire metric specification into imperial units, this is the single most complete concrete conversion reference available.
What Is a Concrete Conversion Calculator?
A concrete conversion calculator is a unit translation tool that converts any concrete-related measurement from one unit system to another without manual calculation. It covers six conversion categories that arise in concrete planning, ordering, design, and construction:
- Volume conversions: Convert concrete quantities between cubic yards (US ordering standard), cubic feet (bag coverage and mix design), cubic meters (international), cubic inches, and liters.
- Length and thickness conversions: Convert project dimensions between inches, feet, yards, meters, centimeters, and millimeters. Critical for translating metric drawings to US ordering units.
- Weight conversions: Convert concrete mass between pounds, US short tons, metric tons (tonnes), and kilograms. Used for truck payload, structural load, and demolition cost planning.
- Strength conversions: Convert compressive strength specifications between PSI (US standard), MPa (international SI), and N/mm² (equivalent to MPa in concrete work).
- Bag and volume conversions: Convert between bag count and concrete volume in cubic feet and cubic yards, and compare cost-per-unit-volume between bags and ready-mix.
- Area conversions: Convert slab surface area between square inches, square feet, square yards, square meters, and square centimeters for coverage and cost-per-square-foot calculations.
Why Concrete Conversions Matter
Unit conversion errors in concrete work are not minor inconveniences. They cause real, expensive, and sometimes irreversible problems:
- Ordering the wrong quantity: A dimension entered in meters treated as feet produces a volume calculation 3.28 times too large. On a 10-yard pour, that error results in an order of 32 yards and a very awkward call to the supplier.
- Specifying the wrong strength: A specification calling for 30 MPa concrete is equivalent to 4,351 PSI—not 30 PSI, not 3,000 PSI. Ordering the wrong strength mix because the conversion was skipped can result in a slab that fails its structural requirement.
- Miscalculating structural loads: A dead load of 75 lbs/sq ft misread as 75 kg/m² (which is actually 15.4 lbs/sq ft) under-estimates the structural load by nearly 5 times—a potentially dangerous error in beam and column design.
- Misreading metric drawings: A wall thickness of 200 mm on a metric drawing is 7.87 inches—not 200 inches, not 200 feet. Treating millimeter dimensions as inches on a large project generates quantity errors across every structure.
Conversion Category 1: Concrete Volume Conversions
Volume Conversion Formulas
Cubic yards → Cubic feet: multiply by 27
Cubic feet → Cubic yards: divide by 27
Cubic yards → Cubic meters: multiply by 0.7646
Cubic meters → Cubic yards: multiply by 1.3080
Cubic feet → Cubic meters: multiply by 0.02832
Cubic meters → Cubic feet: multiply by 35.315
Cubic inches → Cubic feet: divide by 1,728
Cubic feet → Cubic inches: multiply by 1,728
Cubic meters → Liters: multiply by 1,000
Liters → Cubic meters: divide by 1,000
Volume Conversion Reference Table
| Cubic Yards | Cubic Feet | Cubic Meters | Cubic Inches | Liters |
|---|---|---|---|---|
| 0.25 yd³ | 6.75 ft³ | 0.191 m³ | 11,664 in³ | 191.1 L |
| 0.50 yd³ | 13.50 ft³ | 0.382 m³ | 23,328 in³ | 382.3 L |
| 0.75 yd³ | 20.25 ft³ | 0.573 m³ | 34,992 in³ | 573.4 L |
| 1.00 yd³ | 27.00 ft³ | 0.765 m³ | 46,656 in³ | 764.6 L |
| 1.50 yd³ | 40.50 ft³ | 1.147 m³ | 69,984 in³ | 1,146.9 L |
| 2.00 yd³ | 54.00 ft³ | 1.529 m³ | 93,312 in³ | 1,529.2 L |
| 5.00 yd³ | 135.00 ft³ | 3.823 m³ | 233,280 in³ | 3,823.0 L |
| 10.00 yd³ | 270.00 ft³ | 7.646 m³ | 466,560 in³ | 7,646.0 L |
| 20.00 yd³ | 540.00 ft³ | 15.292 m³ | 933,120 in³ | 15,292.0 L |
Conversion Category 2: Length and Thickness Conversions
Length Conversion Formulas
Inches → Feet: divide by 12
Feet → Inches: multiply by 12
Feet → Meters: multiply by 0.3048
Meters → Feet: multiply by 3.2808
Meters → Inches: multiply by 39.370
Inches → Millimeters: multiply by 25.4
Millimeters → Inches: divide by 25.4
Centimeters → Inches: divide by 2.54
Meters → Yards: multiply by 1.0936
Yards → Meters: multiply by 0.9144
Thickness Conversion: Inches to Decimal Feet (Most Used)
| Inches | Decimal Feet | Millimeters | Centimeters | Decimal Yards |
|---|---|---|---|---|
| 1 in | 0.0833 ft | 25.4 mm | 2.54 cm | 0.0278 yd |
| 2 in | 0.1667 ft | 50.8 mm | 5.08 cm | 0.0556 yd |
| 3 in | 0.2500 ft | 76.2 mm | 7.62 cm | 0.0833 yd |
| 4 in | 0.3333 ft | 101.6 mm | 10.16 cm | 0.1111 yd |
| 5 in | 0.4167 ft | 127.0 mm | 12.70 cm | 0.1389 yd |
| 6 in | 0.5000 ft | 152.4 mm | 15.24 cm | 0.1667 yd |
| 8 in | 0.6667 ft | 203.2 mm | 20.32 cm | 0.2222 yd |
| 12 in | 1.0000 ft | 304.8 mm | 30.48 cm | 0.3333 yd |
Feet to Meters Conversion Table
| Feet | Meters | Feet | Meters | Feet | Meters |
|---|---|---|---|---|---|
| 1 ft | 0.305 m | 12 ft | 3.658 m | 60 ft | 18.288 m |
| 2 ft | 0.610 m | 15 ft | 4.572 m | 75 ft | 22.860 m |
| 10 ft | 3.048 m | 30 ft | 9.144 m | 100 ft | 30.480 m |
| 50 ft | 15.240 m | 150 ft | 45.720 m | 300 ft | 91.440 m |
Conversion Category 3: Concrete Weight Conversions
Weight Conversion Formulas
Pounds (lbs) → US tons (short): divide by 2,000
US tons → Pounds: multiply by 2,000
Pounds → Metric tons: divide by 2,204.6
Metric tons → Pounds: multiply by 2,204.6
Pounds → Kilograms: divide by 2.2046
Kilograms → Pounds: multiply by 2.2046
US tons → Metric tons: multiply by 0.9072
Metric tons → US tons: multiply by 1.1023
kg/m³ (density) → lbs/ft³: divide by 16.018
lbs/ft³ → kg/m³: multiply by 16.018
Concrete Weight Conversion Reference Table
| Cubic Yards | Weight (lbs) | Weight (US tons) | Weight (metric tons) | Weight (kg) |
|---|---|---|---|---|
| 0.25 yd³ | 1,013 lbs | 0.506 tons | 0.459 t | 459 kg |
| 0.50 yd³ | 2,025 lbs | 1.013 tons | 0.919 t | 919 kg |
| 1.00 yd³ | 4,050 lbs | 2.025 tons | 1.837 t | 1,837 kg |
| 2.00 yd³ | 8,100 lbs | 4.050 tons | 3.674 t | 3,674 kg |
| 5.00 yd³ | 20,250 lbs | 10.125 tons | 9.185 t | 9,185 kg |
| 10.00 yd³ | 40,500 lbs | 20.250 tons | 18.371 t | 18,371 kg |
| 20.00 yd³ | 81,000 lbs | 40.500 tons | 36.742 t | 36,742 kg |
Conversion Category 4: Concrete Strength Conversions
Strength Conversion Formulas
PSI → MPa: multiply by 0.006895
MPa → PSI: divide by 0.006895 (or multiply by 145.038)
N/mm² → PSI: multiply by 145.038 (N/mm² = MPa)
PSI → kPa: multiply by 6.895
kPa → PSI: divide by 6.895
MPa → kgf/cm²: multiply by 10.197
Concrete Strength Conversion Reference Table
| PSI (US Standard) | MPa / N/mm² (International) | kPa | kgf/cm² | Mix Grade (IS/BS) |
|---|---|---|---|---|
| 1,450 PSI | 10 MPa | 10,000 kPa | 102 kgf/cm² | M10 |
| 3,000 PSI | 20.7 MPa | 20,684 kPa | 211 kgf/cm² | Standard residential |
| 3,500 PSI | 24.1 MPa | 24,132 kPa | 246 kgf/cm² | Driveways, garage floors |
| 4,000 PSI | 27.6 MPa | 27,579 kPa | 281 kgf/cm² | Commercial standard |
| 5,000 PSI | 34.5 MPa | 34,474 kPa | 352 kgf/cm² | High strength |
| 6,000 PSI | 41.4 MPa | 41,369 kPa | 422 kgf/cm² | High-performance |
| 8,000 PSI | 55.2 MPa | 55,158 kPa | 563 kgf/cm² | Ultra-high strength |
Conversion Category 5: Bag to Volume Conversions
Bag Conversion Formulas
Volume (ft³) = Number of bags x Bag yield (ft³)
Volume (yd³) = Volume (ft³) / 27
Bags needed = Volume (ft³) / Bag yield (round up)
Bag yields: 80 lb = 0.60 ft³ | 60 lb = 0.45 ft³ | 40 lb = 0.30 ft³
Bags to Volume Conversion Table
| Number of Bags | 40 lb (0.30 ft³) | 60 lb (0.45 ft³) | 80 lb (0.60 ft³) | Cubic Yards (80 lb) |
|---|---|---|---|---|
| 1 bag | 0.30 ft³ | 0.45 ft³ | 0.60 ft³ | 0.022 yd³ |
| 5 bags | 1.50 ft³ | 2.25 ft³ | 3.00 ft³ | 0.111 yd³ |
| 10 bags | 3.00 ft³ | 4.50 ft³ | 6.00 ft³ | 0.222 yd³ |
| 45 bags | 13.50 ft³ | 20.25 ft³ | 27.00 ft³ | 1.000 yd³ |
| 90 bags | 27.00 ft³ | 40.50 ft³ | 54.00 ft³ | 2.000 yd³ |
| 180 bags | 54.00 ft³ | 81.00 ft³ | 108.00 ft³ | 4.000 yd³ |
Cost per Cubic Yard: Bags vs. Ready-Mix
| Supply Method | Volume per Unit | Cost per Unit (est.) | Cost per Cubic Yard |
|---|---|---|---|
| 40 lb pre-mix bag | 0.30 ft³ (0.011 yd³) | $5 – $7 | $450 – $630 / yd³ |
| 60 lb pre-mix bag | 0.45 ft³ (0.017 yd³) | $7 – $9 | $420 – $540 / yd³ |
| 80 lb pre-mix bag | 0.60 ft³ (0.022 yd³) | $9 – $11 | $405 – $495 / yd³ |
| Ready-mix 3,000 PSI | 1 cubic yard | $130 – $165 | $130 – $165 / yd³ |
| Ready-mix 4,000 PSI | 1 cubic yard | $155 – $195 | $155 – $195 / yd³ |
Conversion Category 6: Area Conversions
Area Conversion Formulas
Square feet → Square yards: divide by 9
Square yards → Square feet: multiply by 9
Square feet → Square meters: multiply by 0.09290
Square meters → Square feet: multiply by 10.764
Square inches → Square feet: divide by 144
Square feet → Square inches: multiply by 144
Square meters → Square yards: multiply by 1.196
Square yards → Square meters: multiply by 0.836
Area Conversion Reference Table
| Square Feet | Square Yards | Square Meters | Square Inches |
|---|---|---|---|
| 1 sq ft | 0.111 sq yd | 0.093 m² | 144 sq in |
| 9 sq ft | 1.000 sq yd | 0.836 m² | 1,296 sq in |
| 100 sq ft | 11.111 sq yd | 9.290 m² | 14,400 sq in |
| 500 sq ft | 55.556 sq yd | 46.452 m² | 72,000 sq in |
| 1,000 sq ft | 111.111 sq yd | 92.903 m² | 144,000 sq in |
Conversion Category 7: Temperature Conversions for Curing
Temperature Conversion Formulas
°F → °C: (°F − 32) x 5/9
°C → °F: (°C x 9/5) + 32
Critical Concrete Temperature Reference Points
| °F | °C | Concrete Action Required |
|---|---|---|
| 32°F | 0°C | Water freezes: do not pour without heated materials and thermal blankets |
| 40°F | 4°C | Minimum air temp for concrete pouring without cold-weather precautions |
| 60°F | 16°C | Optimal curing temperature range begins |
| 70°F | 21°C | Ideal pour and curing temperature |
| 90°F | 32°C | Maximum recommended pour temp without hot-weather precautions |
| 95°F | 35°C | High risk of plastic shrinkage cracking: use retarder, shade, cool water |
Conversion Category 8: Concrete Mix and Water Conversions
Water Volume Conversion Formulas
Gallons → Liters: multiply by 3.7854
Liters → Gallons: divide by 3.7854
Gallons → Pounds: multiply by 8.3454 (water density)
Pounds → Gallons: divide by 8.3454
Liters → Kilograms: multiply by 1.0 (water density = 1 kg/L)
Water per Bag Conversion Reference
| Bag Size | w/c Ratio | Water (lbs) | Water (gallons) | Water (liters) |
|---|---|---|---|---|
| 80 lb bag (cement ~47 lbs) | 0.45 | 21 lbs | 2.52 gal | 9.54 L |
| 80 lb bag (cement ~47 lbs) | 0.50 | 24 lbs | 2.88 gal | 10.90 L |
| 80 lb bag (cement ~47 lbs) | 0.55 | 26 lbs | 3.12 gal | 11.81 L |
| 60 lb bag (cement ~35 lbs) | 0.50 | 18 lbs | 2.16 gal | 8.18 L |
| 40 lb bag (cement ~23 lbs) | 0.50 | 12 lbs | 1.44 gal | 5.45 L |
Master Concrete Conversion Quick Reference Card
| Conversion | Formula | Example |
|---|---|---|
| Cubic yards → cubic feet | x 27 | 3 yd³ x 27 = 81 ft³ |
| Cubic feet → cubic yards | / 27 | 81 ft³ / 27 = 3 yd³ |
| Cubic yards → cubic meters | x 0.7646 | 3 yd³ x 0.7646 = 2.294 m³ |
| Cubic meters → cubic yards | x 1.308 | 2 m³ x 1.308 = 2.616 yd³ |
| Inches → feet | / 12 | 4 in / 12 = 0.333 ft |
| Feet → meters | x 0.3048 | 10 ft x 0.3048 = 3.048 m |
| Millimeters → inches | / 25.4 | 200 mm / 25.4 = 7.874 in |
| Pounds → US tons | / 2,000 | 4,050 lbs / 2,000 = 2.025 tons |
| Pounds → metric tons | / 2,204.6 | 4,050 lbs / 2,204.6 = 1.837 t |
| PSI → MPa | x 0.006895 | 3,000 psi x 0.006895 = 20.7 MPa |
| MPa → PSI | x 145.038 | 25 MPa x 145.038 = 3,626 psi |
| Square feet → square yards | / 9 | 81 ft² / 9 = 9 yd² |
| °F → °C | (°F − 32) x 5/9 | (68°F − 32) x 5/9 = 20°C |
| 80 lb bags → cubic yards | x 0.0222 | 45 bags x 0.0222 = 1.0 yd³ |
Worked Conversion Examples
Example 1: Convert a Metric Concrete Specification to US Units
Given: A 45 m³ concrete pour, 150 mm thick slab, strength C25/30 (30 MPa cylinder), dimensions 15 m x 20 m.
| Item | Metric Value | Conversion Formula | US Result |
|---|---|---|---|
| Length | 15 m | x 3.2808 | 49.21 ft |
| Width | 20 m | x 3.2808 | 65.62 ft |
| Thickness | 150 mm | / 25.4 | 5.91 inches ≈ 6 in |
| Concrete volume | 45 m³ | x 1.308 | 58.86 cubic yards |
| Strength (cylinder) | 30 MPa | x 145.038 | 4,351 PSI ≈ 4,500 PSI mix |
| With 10% waste | 58.86 x 1.10 | — | Order 64.75 yd³ → 65.00 yd³ |
Example 2: Convert Bags to Ready-Mix Order
Given: You estimated 275 x 80 lb bags for a project. Convert to cubic yards for ready-mix comparison.
| Step | Calculation | Result |
|---|---|---|
| Volume from bags | 275 bags x 0.60 ft³/bag | 165 ft³ |
| Convert to cubic yards | 165 ft³ / 27 | 6.11 yd³ |
| Bag cost (at $10/bag) | 275 x $10 | $2,750 |
| Ready-mix cost (at $155/yd³) | 6.11 yd³ x $155 | $947 |
| Ready-mix with delivery/fee | $947 + $75 fee | $1,022 |
| Savings by switching to ready-mix | $2,750 − $1,022 | $1,728 savings |
Example 3: Convert Imperial Project to Metric for International Specification
Given: A 20 x 24 ft garage floor, 4 inches thick, 3,500 PSI. Convert to metric for submission.
| Item | Imperial Value | Conversion Formula | Metric Result |
|---|---|---|---|
| Length | 20 ft | x 0.3048 | 6.096 m |
| Width | 24 ft | x 0.3048 | 7.315 m |
| Thickness | 4 in | x 25.4 | 101.6 mm ≈ 100 mm |
| Concrete volume | 5.93 yd³ | x 0.7646 | 4.53 m³ |
| Strength | 3,500 PSI | x 0.006895 | 24.1 MPa ≈ C25 grade |
| Slab area | 480 sq ft | x 0.0929 | 44.6 m² |
Common Concrete Conversion Mistakes
- Confusing US short tons and metric tons: A US ton is 2,000 lbs. A metric ton (tonne) is 2,204.6 lbs. The difference is 10.2%. On a 20-ton concrete haul-away quote, this is a major discrepancy.
- Treating N/mm² and MPa as different units: They are identical. 1 N/mm² = 1 MPa. A specification listing 25 N/mm² is the same as 25 MPa = 3,626 PSI. No conversion factor is needed between them.
- Using cylinder strength where cube strength is required: European concrete grades list both cylinder and cube strength (e.g., C25/30 = 25 MPa cylinder / 30 MPa cube). The cube strength is approximately 20 to 25% higher than the cylinder.
- Converting millimeters directly as if they were centimeters: 200 mm is 20 cm, not 200 cm. A wall thickness of 200 mm is 7.87 inches—not 78.7 inches. Always verify metric decimal levels before calculating.
- Forgetting that PSI and MPa differ by nearly 145x: 3,000 PSI is not 3,000 MPa. 3,000 PSI is approximately 20.7 MPa. Specifying 3,000 MPa concrete is a specification for material stronger than steel.
Pro Tips for Concrete Unit Conversions
- Label every number with its unit: Labeled calculation details are self-checking and auditable. Lacking labels invites compounding errors.
- For metric to imperial project translation: Convert all dimensions first, write down the converted value list in a single column, then perform the 3D volume calculations. Never alternate systems inside a single formula.
- Memorize the five most-used constants: 27 (ft³/yd³), 0.7646 (yd³/m³), 145 (MPa/PSI factor), 4,050 (lbs/yd³), and 0.3048 (ft/meters). These constants solve 90% of field translation needs.
- Use standard strength lookup tables: 3,000 PSI = M20, 3,500 PSI ≈ M25, 4,000 PSI ≈ M28–M30. Check lookup values instead of manually computing strength grades.