How much clay do I need?
Starting weights for sixty seven things people actually make, on the wheel and by hand. What to wedge up before you sit down, how far a bag goes, and what the number does not cover.
The four numbers most people came here for
Wet weights, before the piece is trimmed and before the kiln takes its cut. The whole chart is underneath.
Sixty seven forms
Search it or filter it. Every weight is what you start with, wet, for a piece that ends up the size in the second column. The bag column takes the middle of the range and assumes every ounce lands on the pot, which is optimistic of it.
Showing 67 forms
| Form | Finished size | Start with | Per bag |
|---|---|---|---|
| Espresso cupours | 2.25 x 2.5 in | 8 oz | 50 |
| Teacup or small cup | 3 x 2.75 in | 8 to 12 oz | 40 |
| Mugours | 3.25 x 4 in | 1 to 1.5 lbplus about 4 oz for the handle | 17 |
| Big 16 oz mug | 3.75 x 4.75 in | 1.5 to 1.75 lbplus about 4 oz for the handle | 13 |
| Tumblerours | 3 x 4.5 in | 1 to 1.25 lb | 22 |
| Pint glass or beer mug | 3.5 x 6 in | 1.75 to 2.25 lbplus about 4 oz for the handle, if it gets one | 11 |
| Wine cup, stemless | 3.25 x 3.5 in | 0.75 to 1 lb | 29 |
| Sake cup | 2.25 x 2 in | 6 to 8 oz | 57 |
| Travel mug | 3.5 x 6.5 in | 2 to 2.5 lbplus about 4 oz for the handle | 10 |
| Yunomi | 3 x 3.75 in | 0.75 to 1 lb | 29 |
| Rice bowl | 4.5 x 2.5 in | 0.75 to 1 lb | 29 |
| Small prep bowl | 5 x 2.5 in | 1 to 1.25 lb | 22 |
| Cereal bowlours | 6 x 3 in | 1.5 to 2 lb | 14 |
| Soup bowl | 7 x 3 in | 1.75 to 2.25 lb | 12 |
| Ramen or noodle bowl | 8 x 4 in | 2.5 to 3.25 lb | 9 |
| Pasta bowl | 9 x 2 in | 2.25 to 3.25 lb | 9 |
| Serving bowlours | 10 x 4.5 in | 3 to 4 lb | 7 |
| Large serving bowl | 12 x 5.5 in | 6.25 to 8.5 lb | 3 |
| Mixing bowl | 10 x 5 in | 4.25 to 5.75 lb | 5 |
| Yarn bowl | 7 x 5 in | 2.5 to 3.5 lb | 8 |
| Berry bowl or colanderours | 6 x 3 in | 1.5 to 2 lb | 14 |
| Pet bowl | 6 x 2.5 in | 1.25 to 1.75 lb | 17 |
| Saucer | 5.5 x 1 in | 1 to 1.5 lb | 20 |
| Bread and butter plate | 6.5 x 0.75 in | 1.5 to 2 lb | 14 |
| Salad or side plate | 8 x 1 in | 2.25 to 3 lb | 10 |
| Dinner plateours | 11 x 1 in | 3 to 4 lb | 7 |
| Large dinner plate | 11.5 x 1.25 in | 4.5 to 6 lb | 5 |
| Charger or platter | 14 x 1.5 in | 6.5 to 8.75 lb | 3 |
| Spoon rest, thrown | 4.5 x 1 in | 0.75 to 1 lb | 29 |
| Bud vase | 2.5 x 5 in | 0.75 to 1 lb | 29 |
| Small vase | 4 x 6 in | 1.75 to 2.25 lb | 12 |
| Vaseours | 5 x 10 in | 4 to 5 lb | 6 |
| Tall vase | 7 x 14 in | 9.25 to 12.25 lb | 2 |
| Bottle | 4 x 8 in | 2.5 to 3.5 lb | 8 |
| Olive oil bottle | 3.5 x 7 in | 1.75 to 2.5 lb | 12 |
| Carafe | 4.5 x 8 in | 3 to 3.75 lb | 7 |
| Small pitcher or creamer | 3.5 x 5 in | 1.25 to 1.5 lbplus about 4 oz for the handle | 15 |
| Pitcherours | 6 x 7 in | 3 to 4 lbplus about 8 oz for the handle | 6 |
| Teapot body | 6 x 5 in | 2 to 2.75 lbplus about 1 lb for the lid, the spout and the handle | 7 |
| Sugar bowl | 4 x 3 in | 0.75 to 1 lbplus about 4 oz for the lid | 22 |
| Honey pot | 3.5 x 4 in | 0.75 to 1 lbplus about 4 oz for the lid and the dipper notch | 22 |
| Small lidded jar | 4 x 4 in | 1 to 1.25 lbplus about 4 oz for the lid | 18 |
| Lidded jar | 5 x 6 in | 2.25 to 3 lbplus about 8 oz for the lid | 8 |
| Large storage jar | 6.5 x 9 in | 5 to 6.75 lbplus about 12 oz for the lid | 4 |
| Canister | 5 x 7 in | 3.25 to 4.25 lbplus about 8 oz for the lid | 6 |
| Utensil crock | 4.5 x 7 in | 3 to 3.75 lb | 7 |
| French butter crock | 4 x 4 in | 1 to 1.25 lbplus about 8 oz for the bell | 15 |
| Garlic keeper | 5 x 4.5 in | 1.5 to 2 lbplus about 8 oz for the lid | 11 |
| Practice cylinder | 4 x 6 in | 2 to 2.75 lb | 11 |
| Small planter | 5 x 4.5 in | 1.75 to 2.5 lb | 12 |
| Planter | 7 x 6 in | 4 to 5.25 lb | 5 |
| Large planter | 10 x 9 in | 10.5 to 14 lb | 2 |
| Casserole | 8.5 x 4.5 in | 3 to 4 lbplus about 1 lb for the lid | 6 |
| Deep baker | 9 x 4 in | 3 to 4 lb | 7 |
| Large pot | 10 x 12 in | 10 to 13.5 lb | 2 |
| Pinch pot | A ball the size of a small orange. No rolling, no slab. | 8 to 12 oz | 40 |
| Slab mug | A wall about 4 by 10 inches plus a base. | 1 to 1.25 lb | 22 |
| Small slab tray | Rolled about 7 by 11 before the edges come up. | 2 to 2.5 lb | 11 |
| Slab platter | Rolled about 12 by 16. | 5 to 6.5 lb | 4 |
| Coil pot, 8 inches tall | Built from coils, not rolled flat. | 4 to 5 lb | 6 |
| Spoon rest | A slab about 4 by 6. | 10 to 12 oz | 36 |
| Soap dish | A slab about 4 by 5 plus a rim. | 10 to 14 oz | 33 |
| Jewelry or ring dish | A slab about 4 by 4. | 6 to 8 oz | 57 |
| Incense holder | A slab about 2 by 7. | 6 to 8 oz | 57 |
| Flat ornament | Cut from a rolled sheet. | 2 to 4 oz | 133 |
| Slab luminary | Four walls about 4 by 6, plus a base. | 2.5 to 3.25 lb | 9 |
| Wall planter | A curved slab about 8 by 10 plus a back. | 3 to 4 lb | 7 |
These run generous on purpose
Most clay weight charts are written by potters who throw for a living. Their walls are an eighth of an inch. Ours assume something closer to a quarter, because that is what comes off the wheel for most of a first year, and a chart that pretends otherwise sends people home with a short pot.
A pound of clay in a practiced hand goes seven or eight inches up the wall. The same pound in a newer hand goes four. Nothing about the clay changed. That gap is most of the range in every row below, and it closes on its own with time at the wheel.
So the low number is what an efficient thrower needs. The high number is what to wedge up while you are still learning. Extra clay costs a few cents. A mug that came out two inches shorter than you wanted costs a month.
One honest limit. No chart can give you an exact number, because the number is not really about the form. It is about how thick you leave the walls, how much you trim away, and how much clay stays on the bat and in the slop bucket. A chart can get you close enough to sit down. The rest is the hundredth pot.
Rolling a slab
Hand built pieces are easier to work out than thrown ones, because a slab is a box. Multiply how long by how wide by how thick, then multiply by 0.07. That is the weight in pounds.
A slab twelve inches square at a quarter inch thick is 12 times 12 times 0.25, which is 36 cubic inches, which is about two and a half pounds. Add a third on top for the offcuts, because nothing gets cut out of a rectangle without waste.
The 0.07 is what a wet stoneware body weighs per cubic inch. It holds for every clay on our shelves, close enough that the difference disappears into the rounding.
For our slab molds the arithmetic is already done. Every one of the seventy five tiles in The Mold Room carries the clay to start with and how thick to roll the slab, which is a better answer than a formula because somebody measured it.
Four things that move the number more than the form does
How thick you leave the walls
This is the whole ballgame. A quarter inch wall against an eighth inch wall is double the clay for the same finished pot.
Whether you trim a foot
A foot ring has to be trimmed out of something. That means throwing the base thick, then carving most of that thickness off and throwing it in the reclaim. Plates and bowls pay this tax hardest.
What never makes it onto the pot
Clay on the bat, clay on your hands, clay in the water. Half a pound goes missing across a morning and nobody ever sees it happen.
Which bag you are holding
Shrinkage runs from about ten percent to about fourteen percent across the clays on our shelves. That moves the finished size more than it moves the starting weight, but on a lid that has to fit a jar, it is the only thing that matters.
The ones that come up
How much clay for a mug?
One pound to a pound and a half for a mug that ends up about three and a quarter inches wide and four inches tall, plus about a quarter pound for the handle. Pull the handle from a separate lump. Running out of clay for the handle is the most common way this goes wrong.
How many mugs can I get out of a bag of clay?
About seventeen, at the middle of that range, with the handles counted. A bag is twenty five pounds. In practice it is fewer, because some of every bag ends up as trimmings and as the lump you never quite got centered.
Should I weigh my clay?
For the first year, yes. Weighing is how you find out that the mug you liked was a pound and a quarter and the one that came out squat was the same pound and a quarter thrown thicker. Once the difference is in your hands you can stop. Plenty of potters never stop.
Do these weights include the handle, the lid or the spout?
No. Every weight is the piece on the wheel. Anything else the form needs is listed beside it, because those get pulled or thrown from their own lump and they are what people forget to wedge up.
Are these wet weights or finished weights?
Wet. This is what you put on the wheel head. A finished piece weighs noticeably less, because the water leaves in the drying and more leaves in the kiln.
Why is your chart heavier than the one in my book?
Because most published charts assume a thrower who has been doing this for years and leaves an eighth inch wall. Ours assume a wall closer to a quarter inch. If you throw thin, use the low number in each row and then take a little off it.
How much clay for a slab?
Length times width times thickness in inches, times 0.07, gives you pounds. Add about a third for offcuts. A quarter inch slab twelve inches square is about two and a half pounds before waste.
What if I am throwing something that is not on this chart?
Find the closest shape and the closest size and start there. A form nobody has named is still a cylinder, a bowl or a plate underneath, and the arithmetic does not know what you are calling it.