Stone Weight Calculator results give the weight of a slab, column, ball, hex paver or boulder from its size and stone type, plus the weight per square foot and how best to move it.
Countertop slabs are usually 2 cm (0.79 in) or 3 cm (1.18 in) thick.
Quantity and Density
Weight by Stone Type
| Stone (ASTM Min) | lb/ft³ | Per Piece | Total |
|---|---|---|---|
| Granite | 160 | 787 lb | 1,573 lb |
| Calcite Marble | 162 | 797 lb | 1,593 lb |
| Dolomite Marble | 175 | 860 lb | 1,721 lb |
| Travertine | 144 | 708 lb | 1,416 lb |
| High-Density Limestone | 160 | 787 lb | 1,573 lb |
| Medium-Density Limestone | 135 | 664 lb | 1,328 lb |
| Low-Density Limestone | 110 | 541 lb | 1,082 lb |
| Quartzite | 160 | 787 lb | 1,573 lb |
| Quartzitic Sandstone | 150 | 738 lb | 1,475 lb |
| Sandstone | 125 | 615 lb | 1,229 lb |
Stone Weight Calculator for Countertops and Boulders
Solid stone is heavy enough that guessing its weight can crack a slab, overload a trailer or hurt someone lifting it. The weight comes from two things, the volume of the piece and the density of the stone it is cut from.
Countertop fabricators and installers use the result to plan carries and cabinet loads. Hardscapers use it for boulders, steps and columns, and homeowners use it before hiring a truck or asking friends to help.
The Stone Weight Calculator works for one piece or a whole order. It also gives the weight per square foot, the tonnage for hauling, a NIOSH-based lifting check and the ASTM density class behind each stone type.
Six Shapes and Ten Stone Types
Pick a shape first in the Stone Weight Calculator. Slab, Tile or Block takes length, width and thickness, while Column takes diameter and height, Ball takes one diameter and Hexagon Paver takes the distance across the flats plus thickness.
Boulder treats a rough stone as an oval with three measured axes, and Known Volume skips the measuring when a supplier already lists cubic feet. Dimensions are in inches, or centimeters in metric mode, and the results come back in pounds, kilograms, short tons and tonnes.
The Stone Type menu covers granite, two marbles, travertine, three limestone grades, quartzite and two sandstones. Choose Custom Density to enter a tested value, and set the number of pieces in the accordion to weigh a full order at once.
How to Calculate Stone Weight
Every shape follows the same rule, whatever the stone. Find the volume of the piece, then multiply it by the density of the stone, keeping both in the same unit system.
$$Weight = V \times \rho$$
The volume formula changes with the shape. A slab or block is a box, a column is a cylinder and a ball is a sphere, each with its own standard geometry formula.
$$V_{slab} = L \times w \times t$$
$$V_{column} = \frac{\pi}{4} d^2 h$$
$$V_{ball} = \frac{\pi}{6} d^3$$
A hex paver uses the across-flats distance s, and a boulder uses its three axis lengths as an ellipsoid. The Stone Weight Calculator applies whichever formula matches the shape you picked.
$$V_{hex} = \frac{\sqrt{3}}{2} s^2 t$$
$$V_{boulder} = \frac{\pi}{6} L W H$$
With dimensions in inches, the volume comes out in cubic inches, and dividing by 1,728 gives cubic feet to multiply by density in lb/ft³. Skipping that step, or mixing feet and inches in one entry, is the most common reason a hand calculation comes out wildly wrong.
Sizes must be above zero, the piece count must be a whole number, and a custom density must fall between 20 and 1,000 lb/ft³. Those limits catch typing slips such as an extra zero rather than any real stone.
ASTM Minimum Densities Behind Each Stone Type
Each preset uses the minimum density in its ASTM dimension-stone specification. Granite comes from ASTM C615, marble from C503, travertine from C1527, limestone from C568 and quartz-based stone from C616. NT Pavers lists all of these minimums together on its ASTM C97 data sheet, C97 being the test method that measures density.
| Stone | ASTM Spec | Min lb/ft³ | Min kg/m³ | Lb per Sq Ft at 2 cm | Lb per Sq Ft at 3 cm |
|---|---|---|---|---|---|
| Granite | C615 | 160 | 2,563 | 10.5 | 15.7 |
| Marble, calcite | C503 | 162 | 2,595 | 10.7 | 15.9 |
| Marble, dolomite | C503 | 175 | 2,803 | 11.5 | 17.2 |
| Travertine | C1527 | 144 | 2,307 | 9.5 | 14.2 |
| Limestone, low density | C568 | 110 | 1,762 | 7.2 | 10.8 |
| Limestone, medium density | C568 | 135 | 2,162 | 8.9 | 13.3 |
| Limestone, high density | C568 | 160 | 2,563 | 10.5 | 15.7 |
| Sandstone | C616 | 125 | 2,002 | 8.2 | 12.3 |
| Quartzitic sandstone | C616 | 150 | 2,403 | 9.9 | 14.8 |
| Quartzite | C616 | 160 | 2,563 | 10.5 | 15.7 |
A minimum is a floor, not a typical value. Many granites test denser, and stone weight calculator pages that assume 170 lb/ft³ put a 3 cm granite slab near 16.7 lb per sq ft, about 6% above the ASTM floor.
If the quarry or fabricator has a C97 test report, enter that density as Custom Density for a closer answer. The fourth card shows the density in use and its specific gravity, which is the density divided by that of water.
Stone Slab Weight per Square Foot
For flat pieces, the first card gives the weight per square foot of face area. It equals the density times the thickness in feet, so a 3 cm granite slab at 1.18 in weighs 15.73 lb per sq ft at the ASTM minimum.
That figure makes the Stone Weight Calculator double as a stone slab weight calculator for countertops. A 120 by 25.5 inch run of 3 cm granite weighs about 334 lb, while a full 120 by 60 inch slab at the same thickness weighs about 787 lb.
Countertop slabs are usually 2 cm or 3 cm thick, and the thickness presets list both with their inch equivalents. Moving from 2 cm to 3 cm adds roughly half again to the weight of every square foot.
Boulders, Balls and Columns
Boulders are where box math goes wrong. A rough granite boulder 36 by 30 by 24 inches weighs about 1,257 lb as an ellipsoid, but treating it as a solid box gives 2,400 lb, an overestimate of about 90%.
Real boulders are lumpier than a smooth oval, so measure the longest, widest and tallest points and treat the result as a planning figure. A 24 inch granite ball weighs about 670 lb, and a 12 inch column 36 inches tall weighs about 377 lb.
Loose stone is a different problem, because the gaps between pieces cut the weight per yard well below a solid block. A cubic yard of solid granite at the ASTM minimum is 4,320 lb, so for gravel and landscape stone use the Crushed Stone Calculator or the River Rock Calculator instead.
For shoreline and slope armor sold by stone class, the Rip Rap Calculator works in tons per area. The Stone Weight Calculator is the better fit when you need the weight of one specific large stone.
Lifting and Hauling the Weight
The second card compares each piece with 51 lb, the load constant in the NIOSH Applications Manual for the Revised Lifting Equation. That is the starting limit for one person under ideal conditions, and real limits drop as the reach, height or twist of the lift gets worse.
Any piece over 51 lb is marked for a team or equipment, since NIOSH gives no separate figure for two people sharing a lift. Slabs call for slab clamps or an A-frame cart and should travel on edge, while boulders, balls and columns call for a dolly, a lifting strap or a loader.
The third card gives the whole order in short tons and metric tonnes for trailer and floor checks. Add the weight of pallets, crates and A-frames on top, since the stone figure covers only the stone.
Stone Weight and Stone Unit Questions
How much does a marble slab weigh in kg?
Switch to metric and enter the size in centimeters. A 300 by 160 cm calcite marble slab 2 cm thick holds 0.096 m³ of stone, and at the ASTM minimum of 2,595 kg/m³ it weighs about 249 kg.
Dolomite marble is denser at 2,803 kg/m³, so the same slab in dolomite weighs about 269 kg. That gap is why the Stone Weight Calculator lists the two marbles separately.
What is 1 stone in kg and pounds?
As a unit of body weight, used mainly in the UK and Ireland, one stone is 14 pounds. With the pound fixed at 0.45359237 kg in NIST SP 811, one stone works out to 6.35029 kg.
A common shortcut says 1 stone is 7 kg, but that runs about 10% high. Seven kilograms is closer to 1.1 stone, and the gap grows quickly at body weights.
How do I convert kg to stones?
Divide kilograms by 6.35029 to get stones, then multiply the decimal part by 14 to get the leftover pounds. For example, 70 kg is 11.02 stone, or 11 st 0.3 lb.
Going the other way, multiply stones by 6.35029. 22 stone is 139.7 kg, and when you weigh several pieces, the hero line of the Stone Weight Calculator shows the order in stones and pounds as well.