When you’re picking materials for ballast or shielding, lead density is key. Industries often pick lead as their heavy metal because it packs a lot of weight into a small space, and it’s cheaper than gold or tungsten.
Our tests show regular industrial lead has a density of 11.34 g/cm³. That means it’s about four times denser than aluminum. This guide will give you lead density numbers in different units. You’ll learn how to figure out relative density and why lead’s atomic setup is so good at blocking strong radiation.
What is the Density of Lead?
When planning radiation shielding or needing heavy ballast, knowing lead’s space-to-weight ratio is key. Lead’s density is about 11.34 g/cm³ (or 11,340 kg/m³) when it’s at room temperature.
We’ve checked this figure through several CNC machining tasks where getting the material weight right (within 0.5% of CAD calculations) is vital. This guide will walk you through the exact density measurements for pure lead, explain how temperature changes these measurements, and show why lead’s atomic makeup makes it great for blocking radiation.
What is the Density of Pure Lead?
Pure lead, at its best (99.99% pure), has a density of 11.342 g/cm³. It’s dense because of its face-centered cubic (FCC) crystal shape, which lets atoms pack close together.
When getting material for exact weights, know the difference between pure lead and lead with antimony. Even a small amount of antimony (like 6%) to make it harder lowers the density to about 10.89 g/cm³. This is a big difference if you need very specific measurements.
Measuring Lead Density: Real-World Methods
Archimedes’ Principle (Water Displacement)
If you have odd-shaped lead castings or scrap, the displacement test is your best bet for finding density. Just drop the lead into a graduated cylinder filled with water and note the volume difference. Divide the lead’s mass by this volume to get the density in grams per milliliter.
Keep the water at 20°C for best results. If air bubbles stick to the lead, tap the cylinder lightly to dislodge them. These bubbles can throw off your density calculation by making it seem 2% to 3% lower than it really is.
Geometric Calculation for Machined Parts
If you are working with a lead brick or cylinder, use a micrometer to measure dimensions to the nearest 0.01 mm. Calculate the volume (V) and weigh the part on a calibrated scale (m), then apply the formula:
This method is preferred in B2B manufacturing for quality control. It allows you to quickly detect internal porosity or “shrinkage” that often occurs during the cooling phase of lead casting.
Density Comparison of Industrial and Precious Metals
| Material | Density (g/cm3) | Density (kg/m3) | Relative Density (SG) |
| Aluminum | 2.70 | 2,700 | 2.70 |
| Steel / Iron | 7.87 | 7,870 | 7.87 |
| Copper | 8.96 | 8,960 | 8.96 |
| Lead (Pure) | 11.34 | 11,340 | 11.34 |
| Mercury | 13.53 | 13,530 | 13.53 |
| Tungsten | 19.25 | 19,250 | 19.25 |
| Gold | 19.32 | 19,320 | 19.32 |
| Platinum | 21.45 | 21,450 | 21.45 |
Factors Affecting Lead Density
Temperature and Thermal Expansion
Lead expands a lot when it gets hot because it has a high coefficient of linear expansion (29*10^-6/K). Its density goes from 11.34 g/cm³ when solid to roughly 10.66 g/cm³ when it melts at 327.5°C.
Alloying Elements
Lead used in manufacturing isn’t usually pure because pure lead is too soft. Alloys like Lead-Antimony or Lead-Tin are tougher but not as heavy. When figuring out your product’s weight, keep the alloy grade in mind so your final product isn’t too light.
How to Calculate Relative Density of Lead?
Calculating the relative density of lead (also known as Specific Gravity) is essential when you need to compare it to water without worrying about units. Since the density of water is 1.00g/cm^3 at 4°C, the relative density of lead is numerically identical to its density: 11.34.
To find this value for a specific alloy, use the formula:
When testing a lead-antimony part in the shop, be sure to use a calibrated hydrometer. Even a slight difference in the RD value can mean there are air pockets inside, which form as the part cools. These voids can impact how well the part works, especially if it’s used in deep-sea, high-pressure conditions.
Does Lead Stop Radiation Only Because of Density?
Many people think lead stops X-rays just because it’s dense. While its density does help by creating lots of atoms for radiation to run into, the thing that really makes lead great at blocking radiation is its atomic number (82).
Lead atoms have many electrons. This makes it more likely that X-rays will be absorbed or scattered through the Photoelectric Effect and Compton Scattering. Because of these, lead can soak up and deflect photon energy better than lighter stuff like concrete or steel.
When you’re building a radiation room, you need to figure out the Half-Value Layer (HVL). For a normal X-ray machine, you only need about 0.25 mm to 0.5 mm of lead to cut the radiation in half. Steel would need to be three times thicker to do the same thing.
Density of Gold vs Lead: Why the Difference Matters
Many people ask, “is lead heavy?” compared to gold. While lead feels extremely heavy in your hand, gold is significantly denser at 19.32 g/cm³. This means a gold bar is nearly 1.7 times heavier than a lead bar of the same size.
In the hardware and jewelry industries, this density gap is the primary way to detect fakes.Besides checking if is gold magnetic,If you weigh a “gold” brick and the density for lead (11.34g/cm^3) shows up on your scale, you know immediately that the core is not genuine gold.
Is Lead Dense? Comparing Lead to Common Metals
When people ask if lead is dense, it all depends on what you’re comparing it to. It’s way denser than regular stuff like aluminum (2.70 g/cm^3) or iron (7.87 g/cm^3).
If you’re in a machine shop, a lead counterweight needs just a quarter of the space that an aluminum one would. But when you look at metals such as platinum (21.45 g/cm^3), lead doesn’t seem so heavy anymore.
Is Lead Heavier Than Gold?
A common query is the density of gold vs lead. Gold (19.32 g/cm^3) is nearly 1.7 times denser than lead (11.34 g/cm^3). If you have two cubes of the same size, the gold cube will be significantly heavier.
In industrial counterfeiting detection, we use this 7.98 g/cm^3 density gap to identify tungsten-core or lead-core fakes. Because tungsten (19.25 g/cm^3) is much closer to gold’s density, lead is rarely used for high-end fakes anymore; it is simply too “light” for the expert eye.
Density for Lead in Various Units
To secure the Google Featured Snippet, we must provide direct answers to unit-specific queries.
- Density of lead kg/m3: The value is exactly 11,340 kg/m³. This is the standard used for large-scale structural calculations in radiation bunker construction.
- Lead density g/ml: Since 1 cm^3 = 1 mL, the density remains 11.34 g/mL. This unit is most common in laboratory displacement tests.
What is density of lead in lb/in3?
For those using the imperial system, lead weighs 0.41 lb/in³.
Denser Than Lead: When Lead Isn’t Enough
Lead is cheap and dense, but aerospace and medical projects sometimes need even denser stuff.
If lead takes up too much space in your design, think about using tungsten alloys (17.0 to 18.5 g/cm^3). You’ll pack about 60% more mass into the same space. Just watch out, because tungsten is tricky to machine. You can cut lead with a hand saw, no problem, but tungsten needs special tools and slower cutting speeds.
Conclusion
Knowing lead density is key, but turning a design into a real, heavy part needs metal know-how. If you’re shielding a hospital or stabilizing a sea platform, the lead grade you pick impacts how long your project lasts.
For important jobs, don’t just go with close enough density numbers, or you might end up with breaks or leaks. Start with 11.34 g/cm^3, but make sure your lead is pure enough for what you’re building.
Get Custom High-Density Lead Solutions
If your project requires precision-engineered lead components with guaranteed density consistency, Baosheng is here to help. From custom high-tolerance industrial weights, we provide technical support to ensure your material specs match your design goals.
Contact Baosheng Today to get a technical consultation and a competitive quote for your high-density lead requirements.
FAQ: Common Questions About Lead Density
What is the density of lead in kg/m3?
The density of lead is 11,340 kg/m³ at room temperature. This unit is primarily used in large-scale engineering and construction to calculate the total weight of radiation shielding walls or ship ballast.
Is lead denser than gold?
No, gold is significantly denser than lead. Gold has a density of 19.32 g/cm³, making it nearly 1.7 times heavier than lead (11.34 g/cm³) for the same volume of material.
How does temperature affect the density of lead?
As lead is heated, its density decreases due to thermal expansion. It drops from 11.34 g/cm³ at room temperature to approximately 10.66 g/cm³ once it reaches its liquid state at 327.5°C.
What is the density of lead in g/ml?
The density of lead is 11.34 g/mL. Because 1 cubic centimeter (cm^3) is equal to 1 milliliter (mL), these two units are used interchangeably in laboratory displacement tests.
Is lead the densest metal?
No, lead is not the densest metal. It is surpassed by several elements, including osmium (22.59 g/cm^3), iridium (22.56g/cm^3), and platinum (21.45g/cm^3), though lead remains the most practical choice for high-weight applications.
