g/cm³ to lb/in³

Aerospace is the one industry that measures density in pounds per cubic inch. An aluminum airframe alloy is 0.0975 lb/in³; a titanium part is 0.160; a steel landing gear fitting is 0.283. The conversion from the datasheet's g/cm³ — aluminum 2.7 — goes through 0.036127292, a number that carries both the 1959 pound and the inch cubed.

1 g/cm³ = 0.0361272920001 lb/in³, and 1 lb/in³ = 27.6799047102 g/cm³. The conversion is a single fixed factor: multiply g/cm³ by 0.0361272920001. Worked: 10 g/cm³ = 0.36127292 lb/in³; 100 g/cm³ = 3.6127292 lb/in³.

By EnginStack Editorial Team | Reviewed against NIST, BIPM and primary-source documentation About →
g/cm³
0.09754369 lb/in³
2.7 g/cm³ = 0.09754369 lb/in³ 2.7 lb/in³ = 74.73574272 g/cm³

Source: NIST SP 811 and the 1959 yard-and-pound agreement (0.9144 m, 0.45359237 kg). Every decimal place in the factor above is a defined constant, not a measurement.

g/cm³ to lb/in³

Aerospace is the one industry that measures density in pounds per cubic inch. An aluminum airframe alloy is 0.0975 lb/in³; a titanium part is 0.160; a steel landing gear fitting is 0.283. The conversion from the datasheet's g/cm³ — aluminum 2.7 — goes through 0.036127292, a number that carries both the 1959 pound and the inch cubed.

lb/in³ = g/cm³ × 0.036127292
1 g/cm³ = 0.036127292 lb/in³ — the 1959 pound over the inch cubed
The factor is exact — derived from SI definitions and the 1959 yard/pound agreement.

Worked Examples

Example 1: Check an aluminum airframe spec against its datasheet

2.7 × 0.036127292 = 0.0975 lb/in³

Example 2: Convert titanium 6Al-4V for a stress report

4.43 × 0.036127292 = 0.1600 lb/in³

Example 3: Convert carbon steel for a landing-gear fitting

7.85 × 0.036127292 = 0.2836 lb/in³

Common g/cm³ to lb/in³ Conversions

g/cm³lb/in³Material / context
1 g/cm³0.0361 lb/in³The definitional anchor.
2.7 g/cm³0.0975 lb/in³Aluminum 6061.
4.43 g/cm³0.160 lb/in³Titanium 6Al-4V.
7.85 g/cm³0.284 lb/in³Carbon steel.
8.96 g/cm³0.324 lb/in³Copper.
19.3 g/cm³0.697 lb/in³Gold.

Engineering Context

Density links the mass and volume families on this site — it is their ratio. For the mass numerator, the kg to g and lbs to kg converters carry the same 1959 constants that appear here; for the volume denominator, the liters to mL and cubic feet to cubic meters pages supply the cubed lengths. The density hub collects all ten converters in this family.

Pounds per cubic inch exists for one reason: the airframe industry weighs structures by volume and buys stock by the pound, and at that scale the numbers are all small. Water is 0.03613 lb/in³, aluminum 0.0975, steel 0.2836, gold 0.697. That is exactly the property that makes the unit dangerous to transcribe: 0.0975 and 0.975 differ by one keystroke, and neither looks absurd on the page. The metric datasheet does not have this problem, because the same materials read 2.7, 7.85 and 19.3 g/cm³, where the ordering is impossible to misread. Converting to g/cm³ is therefore not just a unit change, it is a plausibility check.

More: lb/in³ to g/cm³ · g/cm³ to lb/ft³ · g/cm³ to kg/m³ · Density Guide · Density

Related Unit Converters

lb/in³ to g/cm³ g/cm³ to lb/ft³ g/cm³ to kg/m³ Density Conversion Guide Density Converters

Frequently Asked Questions

Why does aerospace use lb/in³?

Because aircraft weight is computed from inch-based geometry. A part's volume in cubic inches, multiplied by density in lb/in³, gives weight in pounds directly — no foot-to-inch conversion mid-calculation.

Is aluminum really 0.0975 lb/in³?

Yes — 6061 aluminum is about 2.70 g/cm³, which converts to 0.0975 lb/in³. Aerospace weight engineers know it by heart alongside steel's 0.283 and titanium's 0.160.

How does density affect aircraft weight?

Directly — every airframe part's weight is volume × density. Switching from aluminum (0.0975 lb/in³) to titanium (0.160) increases a bracket's weight by 64%.