The minimum billable size is the whole story on small work
Glass is quoted by the square foot, so the natural way to estimate a job is to add up the area and multiply. That works on a tabletop and fails completely on shelves, because almost every fabricator applies a minimum billable area to each piece. Below that figure the piece is charged as if it were that size.
Take six shelves at 30 by 10 inches. That is 2.08 square feet each, 12.5 in total. Against a three square foot minimum each shelf bills as three, so the invoice covers 18 square feet. At fourteen dollars a foot the difference is about 77 dollars on a job whose area suggested 175, which is why the quote comes back higher than anybody expected and why the conversation that follows is uncomfortable.
The reason for the rule is not greed. Cutting, seaming, racking, handling, tempering and packing a small pane costs nearly what the same operations cost on a large one, so a pure area price would lose money on every small piece. The number is on the shop price list. It is rarely on the quote, and it is worth asking for by name.
Where else the money goes
Edge work is priced by the linear foot and it adds up faster than people expect on small pieces, because small pieces have a lot of perimeter relative to their area. A 30 by 10 shelf has 80 inches of perimeter around 2.08 square feet. A 48 by 24 tabletop has 144 inches around 8. The shelf carries more than twice as much edge per square foot as the tabletop, so on a shelf job the edge line can approach the glass line.
Holes are priced per hole, and the important thing about them is not the price. Holes have to be drilled before tempering. A pane that comes back from the oven and then needs a hole is a pane that has to be remade, so the hole positions are part of the order and not part of the installation.
The minimum order charge works differently from the minimum billable size: it applies to the order as a whole rather than to each piece, and it means a small job costs the same as a slightly larger one. If your order lands just under it, adding a spare shelf costs nothing, which is worth knowing before deciding not to order the spare.
What the total here is and is not
It is the arithmetic on the numbers you entered, and nothing else. There are no market prices on this page and there is no built-in allowance for the things that turn up on a real invoice: templating, a site visit, working from a pattern, a rush charge, a different grade of edge polish, oversize handling, breakage cover, or a tempering line if the shop quotes it separately from the glass.
Sales tax is a field and starts at zero because rates and what is taxable vary by state and by locality, and because a fabrication-and-installation job is not always taxed the same way as a supply-only one. Put your own rate in. Nothing about tax treatment is stated here.
How to get a quote you can compare
Ask for the price list rather than a quote for the job. Three numbers make every subsequent quote readable: the rate per square foot for the thickness and treatment you want, the minimum billable area per piece, and the minimum order value. With those, you can price a change to the schedule yourself and see immediately whether splitting a large piece into two or combining two small ones into one moves the total.
Then send the cut list in writing, with every dimension, every hole position and every notch on it. Tempered glass cannot be cut, drilled or notched once it has been through the oven, so there is no correcting anything afterwards — a mistake is a new pane at full price and another lead time. That is also why fabricators want the sizes confirmed rather than estimated, and why a site measure by the person making the glass is often worth what it costs.
The part that is not about money
Nothing on this page says what thickness anything should be, whether a location requires safety glazing, or what treatment a shelf, a door or a tabletop calls for. Those come from your fabricator and from the code your jurisdiction has adopted, and they are decided before the price is. Annealed glass in a location that called for something else is the specific hazard, and the pane that saved money on the order is the one that breaks into long shards.
Questions people ask
Why is my glass quote higher than the square footage suggests?
Almost certainly the minimum billable area per piece. Most fabricators charge each pane as if it were at least a set size, commonly a few square feet, however small it actually is. Six shelves at 30 by 10 inches are 12.5 square feet of glass and bill as 18 against a three square foot minimum. The page shows the two figures side by side and works out what the gap costs at your rate.
What is a minimum order charge and can I get around it?
It is a floor on the order value rather than on each piece, and no, but you can make it work for you. If the order lands under the minimum you pay the minimum anyway, so anything you add up to that point is effectively free. A spare shelf, a second cabinet door or a piece you were going to order next month all cost nothing if the order is short of the floor. The page reports the top-up explicitly so you can see how much room there is.
How much does edge polishing add?
It is priced per linear foot, so what it adds depends on perimeter rather than area — and small pieces have far more perimeter per square foot than large ones. A 30 by 10 shelf has 80 inches of edge around two square feet of glass; a 48 by 24 top has 144 inches around eight. On a job of small pieces the edge line can come close to the glass line, which is why the page prices all four edges and two edges separately.
Can holes be added to tempered glass later?
No. Every hole and every notch has to be made before the glass goes into the tempering oven, and attempting one afterwards destroys the pane. That makes hole positions part of the order rather than part of the installation, and it is the main reason fabricators want a dimensioned drawing rather than a description. A missed hole is a new pane at full price and another lead time.
Does this include tax and delivery?
Only if you put them in. Both are fields and both start at zero or your own figure, because delivery is quoted job by job and tax rates and taxability vary by state and locality — a supply-only order is not always treated the same as supply and install. Nothing about tax treatment is stated on this page. Put your own rate in and the line appears.