Density times volume, and the volume is bigger than it looks
There is only one calculation here. Work the piece out in cubic feet, multiply by the density, and you have pounds. What makes it worth a page is that people are consistently wrong about the cubic feet, because a monument is a box in three directions and the eye only tracks two of them.
A 36 by 24 inch die reads as a modest stone. At 8 inches thick it is 6,912 cubic inches, which is exactly 4 cubic feet, which at 170 pounds a cubic foot is 680 pounds. Put it on a 48 by 12 by 8 base and the base adds 2.67 cubic feet, or 453 pounds. The pair is 1,133 pounds before anybody has touched it. Nothing about that is a large monument.
| Piece | Inches | Cubic feet | At 170 lb/cu ft |
|---|---|---|---|
| Flush marker | 24 x 12 x 4 | 0.67 | 113 lb |
| Slant marker | 24 x 16 x 16 | 3.56 | 604 lb |
| Small die | 24 x 6 x 18 | 1.50 | 255 lb |
| Die as above | 36 x 8 x 24 | 4.00 | 680 lb |
| Base as above | 48 x 12 x 8 | 2.67 | 453 lb |
| Companion die | 60 x 8 x 30 | 8.33 | 1,417 lb |
Read down the last column and the design conversation changes shape. The step from a 36 inch die to a 60 inch companion die is not a step in price alone. It is the step from something a small crew and a light machine handle to something that is not.
Thickness is the cheapest dimension to add and the most expensive to carry
Length and height are what the customer sees. Thickness is what the customer never mentions and what the weight is proportional to just the same. On a 36 by 24 die, one extra inch of thickness is 864 cubic inches, half a cubic foot, about 85 pounds. Going from 6 inch stock to 8 inch on that die is 170 pounds, a third more than the 6 inch die weighed, for a change nobody notices from the front.
That is not an argument for thin stock. Thickness is what stops a tall die reading as flimsy, and the proportions of monument work are conventional for good reasons. It is an argument for knowing which number moved when the design changed, because the weight is what decides what has to be on site to receive it.
The bearing number is a division, not a verdict
Weight over footprint gives pounds per square foot, and the calculator reports it because it is a useful thing to have written down. It is not a soil check, a foundation check or a permission. A monument foundation is designed to whatever the cemetery requires, in the depth and reinforcement the cemetery specifies, and both of those are cemetery rules rather than general facts — they vary with local ground, with local frost, with what the cemetery has decided it wants, and they change. The foundation question goes to the cemetery office and the monument dealer, in that order, before the order is placed.
What the page deliberately does not do
It does not tell you how to lift anything, what to lift it with, or how many people to have on it. Monument setting is specialist work: the stone is heavy, it is smooth, the ground is soft, and a stone that goes over crushes whatever is beneath it without any warning worth the name. The pounds are here so that the conversation with the people who do the setting starts from a real number instead of a guess.
Questions people ask
How much does granite weigh per cubic foot?
It is usually taken somewhere near 170 pounds a cubic foot, which works out to about 2.7 grams per cubic centimetre. Real figures move with the quarry and the colour — some dark granites and gabbros run noticeably heavier, and some light grey stone a little lighter. The page takes it as an input rather than a constant for that reason. If the weight matters enough to matter, the quarry or the fabricator can give you the figure for the stone in front of you, and the difference between 165 and 180 on the four cubic foot die worked through below is 60 pounds, and on a piece twice that size it is 120.
How heavy is a typical headstone?
There is no typical, which is why the arithmetic is worth doing. A flush marker 24 by 12 by 4 inches is around 113 pounds. An upright die 36 by 8 by 24 on a 48 by 12 by 8 base is about 1,133 pounds for the pair. A companion monument with a 60 inch die and a base to suit goes well past a ton. The pattern is that the pieces people describe as small are still two-person or machine work, and the pieces people describe as ordinary are machine work only.
Does the calculator tell me whether my equipment can lift it?
No, and it is built not to. It reports the weight of each piece, and if you type in a rating it restates that rating beside the weight and divides one by the other. That is arithmetic on two numbers you supplied. Whether a particular machine, sling, clamp or configuration suits a particular lift on particular ground is a question for the equipment maker and for the people who do the setting, and no page can answer it from three dimensions and a density.
Should I include the foundation in the weight?
Not in these numbers — the calculator weighs stone above ground. The foundation is concrete, it is a separate order, and what it has to be is set by the cemetery rather than by the monument. If you want the concrete quantity, work the footprint and depth the cemetery gave you through the concrete slab calculator. Do not size a monument foundation from a general rule found online; the rule that governs is the one the cemetery hands you in writing.
How do I account for a shaped top or a carved face?
With the shape deduction field, using your own estimate. A serp top removes a shallow lens of stone from a rectangle and typically takes a few percent off; an oval top or a heavily shaped design takes more. There is no general figure because the shape is whatever was drawn. If you need it close, ask the fabricator what the rough block for that shape works out to — they price the block, so they already know.