Tungsten vs Steel Density: What the Numbers Actually Mean

Tungsten is 19.25 g/cm³ and steel is 7.85, so is a tungsten part 2.45 times heavier than the same part in steel? Only if the part is pure tungsten and the steel is plain carbon steel. Many tungsten parts are heavy alloy, steel is not a single number, and the ratio for our most-shipped grade, Class 2 heavy alloy, is 2.2 to 2.3 times. This guide puts the real density figures side by side, shows what the ratio does to a part’s weight and size, and covers how to check a density number before you design around it.

Tungsten vs Steel Density at a Glance

Steel figures come from the Physics Factbook’s survey of published steel densities, which found plain carbon steel at 7.85 to 7.86 g/cm³, and from Rolled Alloys’ 304 data sheet, which lists 0.285 lb/in³. The heavy alloy ranges are the ones in our ASTM B777 class breakdown. Why tungsten lands so far above everything else on the table is the subject of the atomic reason tungsten is so dense.

Which Steel and Which Tungsten Are You Comparing?

The spread sits on the tungsten side. Published steel densities run from about 7.75 to 8.05 g/cm³, a spread of under 4 percent, and 304 stainless is at most about 2 percent above carbon steel. Call steel 7.85 and move on, the error is small.

Tungsten is different. ASTM B777 sets four classes of heavy alloy by tungsten content, 90 percent in Class 1 up to 97 percent in Class 4, and the allowed density climbs from 16.85 to 18.85 g/cm³. That is a spread of nearly 12 percent inside one standard. Pure tungsten sits above all of it at 19.25, which is within about a quarter of a percent of gold, as we cover in our comparison with lead and gold.

So “tungsten is 2.5 times denser than steel” is a loose statement. Against carbon steel the honest range is 2.15 to 2.4 times for heavy alloy and 2.45 for the pure metal. The class on the drawing decides where in that range you land.

What the Ratio Does to a Real Part

The same ratio reads three ways, and which one matters depends on what you are holding fixed. Take a block that is 2 in by 2 in by 1 in, which is 4 in³.

• Same size: the steel block weighs 1.13 lb. In TPW’s Class 2 heavy alloy at 17.5 g/cm³ it weighs 2.53 lb, and in pure tungsten 2.78 lb.
• Same weight: to hit 1.13 lb in Class 2 you need 1.79 in³, which is 45 percent of the steel volume. With the same 2 by 2 footprint the plate is 0.45 in thick instead of 1 in. Pure tungsten would need 41 percent.
• Same moment: a counterweight works as mass times distance from the pivot. If the arm cannot get longer, the mass has to come from somewhere, and density is how you fit it in. How aerospace uses counterweights and ballast goes through the cases where that constraint is real.

“2.2 times denser” does not mean “2.2 times smaller”. Volume goes as the inverse, so the part shrinks to 45 percent of its old size, a reduction of 55 percent. The weights of standard cube sizes in both materials are tabulated in our cube weight chart.

Why the Datasheet Number Is a Range

ASTM B777 gives each class a density window, not a point. Class 2 allows 17.15 to 17.85 g/cm³, and our certified lots run 17.5 to 17.7 inside it. A 1 in cube of that material weighs between 0.632 and 0.639 lb. The same cube in pure tungsten weighs 0.695 lb.

That gap is easy to miss on a drawing. If a part is sized from the pure tungsten figure and then built in Class 2, it comes out about 9 percent lighter than planned. Sized from 17.0 and built in Class 4 at 18.5, it comes out about 9 percent heavier. Put the class on the drawing and size the part from that class’s density.

How to Check Density Yourself

You need a scale and a bucket of water. Weigh the part dry, then weigh it hanging fully submerged on a thread. Density is the dry weight times the density of water (about 0.998 g/cm³ at room temperature) divided by the difference between the two readings. Labs run the same method, and ASTM B962 is the standard test method for sintered powder metal parts.

Here is what a 1,000 g piece reads when submerged, depending on what it is made of:

A piece that reads 943 g works out to 17.5 g/cm³, which is squarely inside Class 2. Steel cannot do that, and neither can lead. Density will not separate pure tungsten from gold, and it says nothing about what the binder is, so treat it as a screen, not a certificate. A magnet helps less than people expect: carbon steel grabs it hard, but 304 stainless barely does, nickel-iron heavy alloy is slightly magnetic, and nickel-copper heavy alloy is not magnetic at all.

This matters most when you inherit unmarked weights. A counterweight that gets binned as heavy steel is a loss, because heavy alloy keeps real value at end of life. If the water test says tungsten, what Tungsten Buyers accepts lists the forms it takes, and the sample and assay process is how the actual tungsten content gets measured before any price is quoted.

Where Density Is Only Half the Story

Density tells you how much mass fits in a space. It does not tell you how stiff or strong the part is, and it does not tell you what the part costs. Heavy alloy is also stiffer than common steels and, in our Class 2, stronger than structural steel, which is the story in our stiffness and strength comparison with steel. It is also far more expensive per pound, so the switch only pays off when the density is doing real work.

When the Extra Density Pays for Itself

The cases are the ones where mass has to fit inside a fixed envelope: counterweights and ballast, balance weights, and tooling where a larger steel part simply will not go.

Bucking bars are the clearest everyday example, because mass is the product. A bar has to be heavy enough to hold the rivet while it is set, small enough to reach it, and shaped for the access. Our sister brand USA Tungsten built a tool for that trade-off: its bucking bar selector asks where the rivet sits, how tight the access is, what size the rivet is, and whether you want the bar as light as possible, balanced, or at maximum mass, then recommends a bar. Our class breakdown notes that Class 3 in particular is what gets machined into these bars.

Frequently Asked Questions

How much denser is tungsten than steel?

Pure tungsten is 19.25 g/cm³ against 7.85 for carbon steel, about 2.45 times. Tungsten heavy alloy, which is what most parts are made from, runs 16.85 to 18.85 g/cm³ depending on the ASTM B777 class, or 2.15 to 2.4 times as dense as carbon steel. TPW’s certified Class 2 lots are about 2.2 to 2.3 times.

What is the density of steel in lb/in³ and kg/m³?

Carbon steel is about 0.284 lb/in³ and 7,850 kg/m³. Stainless 304 is slightly higher, around 0.285 to 0.289 lb/in³, or roughly 7,900 to 8,030 kg/m³ depending on the source.

Is tungsten heavy alloy denser than stainless steel?

Yes, by about 2.2 times. Stainless 304 is about 8.0 g/cm³ and Class 2 heavy alloy is 17.5 to 17.7.

How do I convert g/cm³ to lb/in³?

Multiply by 0.03613. For example, 17.5 g/cm³ is 0.632 lb/in³. To go the other way, multiply lb/in³ by 27.68.

Is specific gravity the same as density?

They give nearly the same number at room temperature, because water is close to 1 g/cm³. Specific gravity has no units. It is the ratio of the material’s density to water’s, so a specific gravity of 17.5 means 17.5 times water.

Can I tell tungsten from steel without a lab?

Mostly, yes. Tungsten alloy feels about twice as heavy as a steel piece of the same size, and a bucket-and-scale density check separates them cleanly. A magnet alone will not settle it, because some stainless steels and nickel-copper heavy alloy are both nonmagnetic.

Tungsten Parts Wyoming manufactures tungsten and tungsten heavy alloy components, powder to finished part, in Laramie, Wyoming, under ISO 9001. Send us the steel part you want to replace, or a drawing, through our quote form, and we will price the heavy alloy version. Our tungsten heavy alloy page lists the grades, and full density data by class is on our technical data page.