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The density in kilograms per cubic metre.
Use the density the receiving calculation actually expects. For a concrete mix that is normally the fresh or the equilibrium hardened density, not the oven-dry figure quoted for an aggregate. Check first that your source is mass density in kg/m³ and not weight density in kN/m³ — if the number sits near 24 rather than 2400, it is kN/m³ and needs multiplying by roughly 102 before it comes in here.
Unit weight
149.8 lb/ft³
Converted using an exact defined factor of 0.06242796057598927 lb/ft³ per kg/m³. Fixed by the 1959 definitions of the pound and the foot; the only judgement left is whether the density you typed is the one your specification means.
- Conversion factor applied
- 0.06 lb/ft³ per kg/m³
They open the calculator with your figures already in it
kg/m³ to pcf Calculator: 150 lb/ft³ — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- 1 lb = 0.45359237 kg exactly and 1 ft = 0.3048 m exactly (international yard and pound agreement, 1959), so 1 ft³ = 0.028316846592 m³ exactly and 1 lb/ft³ = 0.45359237 ÷ 0.028316846592 = 16.018463373960139… kg/m³. This page applies the reciprocal, 1 kg/m³ = 0.062427960576144612… lb/ft³. The ratio is fixed by definition, but its decimal expansion does not terminate — the value carried here is that exact ratio rounded, not a measured or approximate constant.
Inputs used
- Density (kg/m³)
- 2400
Intermediate steps
- Conversion factor applied
- 0.06 lb/ft³ per kg/m³
Confidence note: Converted using an exact defined factor of 0.06242796057598927 lb/ft³ per kg/m³. Fixed by the 1959 definitions of the pound and the foot; the only judgement left is whether the density you typed is the one your specification means.
Add the equipment this sizes
This result is a specification — 149.8 lb/ft³ — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-08-26 · in the site-wide review of 2026-09-06 · v1.0.0
Regulatory standards & verification citations1
- 1 lb = 0.45359237 kg exactly and 1 ft = 0.3048 m exactly (international yard and pound agreement, 1959), so 1 ft³ = 0.028316846592 m³ exactly and 1 lb/ft³ = 0.45359237 ÷ 0.028316846592 = 16.018463373960139… kg/m³. This page applies the reciprocal, 1 kg/m³ = 0.062427960576144612… lb/ft³. The ratio is fixed by definition, but its decimal expansion does not terminate — the value carried here is that exact ratio rounded, not a measured or approximate constant.
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Your workspace
Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.
A mix design, an aggregate datasheet or a Eurocode material table gives density in kg/m³, and the calculation waiting for it is American — an ACI modulus expression, a US ready-mix quote, a spreadsheet written around pcf. The trap here belongs to the metric side, which has two units in circulation. Continental structural documents often state weight density in kN/m³ rather than mass density in kg/m³, and a 24 typed in as though it were 2400 lands the answer a factor of 9.8 out. The second is habit: 2400 kg/m³ is 149.83 pcf, not 150. Round it up before it enters a term raised to the power 1.5 and the error grows past the tenth of a percent you thought you were accepting.