Imperial to Metric Converter — Concrete Units

Convert concrete measurements between imperial and metric instantly. Volume, strength, length, area, weight — every unit a contractor or engineer actually uses on a jobsite or in a spec sheet.

Free to use No sign-up required NIST & SI-standard conversion factors Bidirectional: imperial ↔ metric

✓ Volume: yd³ ↔ m³, ft³ ↔ m³ ✓ Strength: PSI ↔ MPa ✓ Length: ft / in ↔ m / mm ✓ Weight: lb / ton ↔ kg / tonne

Reviewed by the AllConcreteCalculator.com editorial team — conversion factors verified against NIST Handbook 44 and SI standards, May 2026.

Convert Concrete Units

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How to Use This Imperial to Metric Converter

Select the measurement category. Tap the category tabs at the top of the calculator: Volume, Strength (PSI ↔ MPa), Length, Area, Weight, or Truck Load/Flow. The input and output unit options update automatically to match that category.
Set the conversion direction. Click "Imperial → Metric" if you have a US value and need the SI equivalent — for example, you know a slab is 2.5 yd³ and need to tell a metric-country supplier how many m³ to deliver. Click "Metric → Imperial" if you're reading a European spec sheet and need to convert to what your US supplier quotes.
Enter your value and select input and output units. Type the number in the value field. Use the input unit dropdown to pick the specific unit (e.g. yd³ vs ft³). Then pick your desired output unit. The converter shows your primary result plus all common equivalents in one shot — no need to run separate calculations.
Copy or print the results for your records. Use the Copy button to grab the full result block for a project quote, an email to your supplier, or a RFI response. Use Print to produce a clean hardcopy for the jobsite file. All results display the exact conversion factor used so you can verify the math independently.

⚠ Pro Tip: The most dangerous unit mix-up in concrete isn't imperial vs metric — it's cubic feet vs cubic yards. 1 yd³ = 27 ft³, not 3. If you're quoting a ready-mix order in yd³ but your calculation was in ft³ and you forgot to divide by 27, you'll order 27× too little. Always confirm which cubic unit your supplier prices by before placing the order.

Conversion Formulas — All Concrete Units

Every conversion factor below is exact or rounded to six significant figures, per NIST SP 1038 (The International System of Units). These are the same factors used in ACI 318M (metric edition) and BS EN 206.

Category	Imperial → Metric	Metric → Imperial
Cubic Yards → Cubic Meters	× 0.764555	× 1.30795
Cubic Feet → Cubic Meters	× 0.0283168	× 35.3147
Cubic Inches → Liters	× 0.0163871	× 61.0237
PSI → MPa (N/mm²)	× 0.00689476	× 145.038
Feet → Meters	× 0.3048	× 3.28084
Inches → Millimeters	× 25.4	× 0.0393701
Square Feet → Square Meters	× 0.0929030	× 10.7639
Square Yards → Square Meters	× 0.836127	× 1.19599
Pounds → Kilograms	× 0.453592	× 2.20462
Short Tons (US) → Metric Tonnes	× 0.907185	× 1.10231
lb/ft³ → kg/m³	× 16.0185	× 0.0624280
yd³/hr → m³/hr	× 0.764555	× 1.30795

Common Concrete Value Quick-Reference Table

Pre-converted common concrete values. Add your own waste factor as needed.
Imperial Value	Metric Equivalent	Context
1 yd³	0.765 m³	Smallest ready-mix truck load increment
5 yd³	3.82 m³	Typical small residential pour
10 yd³	7.65 m³	Standard mixer truck full load (US)
3,000 PSI	20.7 MPa	Minimum residential slab / walkway
3,500 PSI	24.1 MPa	Residential driveway / garage floor
4,000 PSI	27.6 MPa	Commercial slab / freeze-thaw exposure
5,000 PSI	34.5 MPa	High-strength structural concrete
4 in	101.6 mm	Standard residential slab thickness
6 in	152.4 mm	Driveway / garage slab thickness
12 in	304.8 mm	1 foot — column diameter reference
150 lb/ft³	2,403 kg/m³	Normal-weight (NW) concrete density
1 short ton (US)	0.907 metric tonne	Aggregate / cement bulk delivery

All factors per NIST SP 1038. PSI ↔ MPa: 1 MPa = 1 N/mm² exactly.

When to Use PSI vs MPa — Reading Concrete Spec Sheets

The single most common unit confusion on international concrete projects is compressive strength: US projects specify f'c in PSI; European, Australian, and Canadian projects (and ACI 318M) use MPa. The values look wildly different — 4,000 PSI and 27.6 MPa describe exactly the same concrete — which is why verifying the unit system before ordering is non-negotiable.

PSI to MPa equivalents for common concrete strength classes used in US and international specs.
PSI (f'c)	MPa (f'c)	Typical Application	Standard Class
2,500 PSI	17.2 MPa	Mass fills, lean concrete base	C17 (EN206)
3,000 PSI	20.7 MPa	Residential slab, walkway, patio	C20 (EN206)
3,500 PSI	24.1 MPa	Driveway, garage floor, mild exposure	C25 (EN206)
4,000 PSI	27.6 MPa	Commercial slab, freeze-thaw, XF1	C28 / C30 (EN206)
4,500 PSI	31.0 MPa	Structural beams, footings	C30 (EN206)
5,000 PSI	34.5 MPa	High-strength structural, bridges	C35 (EN206)
6,000 PSI	41.4 MPa	Precast, high-rise columns	C40 (EN206)
8,000 PSI	55.2 MPa	Ultra-high-strength structural	C50+ (EN206)

EN 206 characteristic cylinder strength classes (C20, C25…) are tested on 150×300 mm cylinders. US compressive strength (PSI) uses 4×8 in or 6×12 in cylinders. The test protocols differ slightly, so exact cross-comparison requires checking the specimen geometry in the spec sheet. For most practical ordering purposes, the direct PSI × 0.00689 = MPa conversion is accurate enough.

Common Mistakes When Converting Concrete Units

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Confusing cubic feet with cubic yards when ordering ready-mix. Ready-mix is ordered by the cubic yard in the US. If your calculation gives you 54 cubic feet and you call in "54" to the plant expecting yards, you'll get 54 yd³ — 27× what you need. Always convert ft³ ÷ 27 = yd³ before phoning your supplier, or use the volume converter on this page to verify before you call.
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Treating PSI and MPa as proportional to the same scale. 4,000 PSI is roughly 27.6 MPa. A contractor used to PSI who sees "27 MPa" on a European spec might dismiss it as "weak concrete." It's not — it's exactly the same as a standard commercial slab. Always convert before comparing strength specifications across standards.
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Using short tons (US) instead of metric tonnes (or vice versa). One US short ton = 2,000 lb = 0.907 metric tonnes. One metric tonne = 1,000 kg = 2,204.6 lb. On aggregate deliveries, confusing the two units on a large order can mean receiving 10% less material than expected — enough to stop a pour mid-job.
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Converting rebar sizes directly instead of using the correct designation system. US rebar sizes (#3, #4, #5…) are in eighths of an inch. They don't convert directly to metric rebar (10M, 15M, 20M…) by name — a #4 bar is 12.7 mm diameter, which corresponds roughly to a 13M (metric) bar, not a 10M or 15M. Always use a rebar cross-reference table, not a raw diameter conversion, when substituting metric for US rebar.
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Applying the wrong density when converting concrete weight to volume. Normal-weight concrete is approximately 150 lb/ft³ (2,403 kg/m³). Lightweight concrete can be 90–115 lb/ft³ (1,440–1,840 kg/m³). If you're backing out a volume from a weight (e.g., from a truck ticket), confirm whether you're dealing with NW or LW mix before dividing — using 150 lb/ft³ for a lightweight pour will overestimate the volume placed by 30% or more.

Frequently Asked Questions

Multiply the number of cubic yards by 0.764555 to get cubic meters. For example, 10 yd³ × 0.764555 = 7.646 m³. To go the other way, multiply cubic meters by 1.30795. This is the exact conversion used by ACI 318M and international ready-mix suppliers. The factor comes from the fact that 1 yard = 0.9144 meters exactly, so 1 yd³ = (0.9144)³ = 0.764555 m³.
3,000 PSI = 20.68 MPa. The conversion is PSI × 0.00689476 = MPa. In European standards (EN 206), this falls close to the C20/25 concrete class, which has a characteristic cylinder strength of 20 MPa. Standard residential slabs in the US are specified at 3,000 PSI (20.7 MPa). For freeze-thaw environments, 4,000 PSI (27.6 MPa) is standard — which approximates C28/35 in European notation.
Exactly 0.764555 cubic meters. This is a fixed, exact relationship derived from the definition that 1 international yard = 0.9144 meters. Cubing that gives 1 yd³ = 0.764555 m³. On a typical 10-yard ready-mix truck, you receive 7.646 m³ of concrete. Metric countries order concrete in cubic meters; one standard metric truck is usually 6–8 m³, which is about 7.8–10.5 yd³.
Multiply inches by 25.4 to get millimeters (1 inch = 25.4 mm exactly by definition). Common concrete slab thicknesses: 4 inches = 101.6 mm, 6 inches = 152.4 mm, 8 inches = 203.2 mm. To go from mm to inches, divide by 25.4. On international projects, slab thickness is typically specified in whole millimeters — 100 mm, 150 mm, 200 mm — which differ slightly from the US standard inch equivalents.
Normal-weight (structural) concrete has a density of approximately 150 lb/ft³ in imperial units, or 2,403 kg/m³ in metric. To convert lb/ft³ to kg/m³, multiply by 16.0185. Lightweight concrete typically runs 90–115 lb/ft³ (1,440–1,840 kg/m³). Heavyweight concrete (used for radiation shielding) can reach 200–250 lb/ft³ (3,200–4,000 kg/m³). The density you use matters when calculating structural loads, transport weights, and pump pressure requirements.
No — they are close but different. A US short ton is 2,000 lb (907.185 kg). A metric tonne is exactly 1,000 kg (2,204.6 lb). A metric tonne is therefore about 10.2% heavier than a US short ton. On bulk material deliveries (cement, aggregate, fly ash), mixing up these units leads to significant under-ordering. There is also a "long ton" used in some British contexts, equal to 2,240 lb (1,016 kg) — different again. Always confirm which "ton" a quote refers to before accepting delivery quantities.
Multiply square feet by 0.0929030 to get square meters. Or divide by 10.7639. For example, a 20 × 20 ft slab = 400 ft² × 0.0929 = 37.16 m². This area conversion matters when working with metric sealer coverage rates, metric rebar spacing specs, or pricing from international suppliers who quote per m². Conversely, if a spec gives you an area in m² and you need sq ft for a US estimate, multiply by 10.7639.
Plants near the US-Canada border and plants serving multinational contractors often print both units to reduce billing disputes. Canada officially uses metric (m³) while the US uses cubic yards — but many Canadian plants near the border still accept orders in either unit. The ticket will show the actual volume loaded (typically in the billing unit) and the equivalent in the other system. If you see a discrepancy, check whether the plant is printing net vs gross volume — some tickets include the drum wash water volume separately.
MPa (megapascals) measures compressive strength — how much pressure the concrete can withstand before crushing. Higher MPa means higher strength, but it also means higher cement content, higher heat of hydration, higher shrinkage potential, and higher cost. For a residential patio (20–25 MPa / 3,000–3,500 PSI), going to 40 MPa adds cost and shrinkage risk with no practical benefit. Always match the specified strength to the load and exposure conditions — overspecifying is not free and can actually cause problems in mass pours.