How much royal icing for a gingerbread house
A 5 × 6 in house needs about 1.25 cups of royal icing to hold it together, a classic 6 × 8 in house about 1.25 cups, and a showpiece 10 × 12 in about 2.25 cups. Recipes usually give one batch "for a house". This page works the amount out for the size you are building, from the length of every joint.
| House | Footprint | Glued seams | Piped | Mix | Powdered sugar |
|---|---|---|---|---|---|
| Mini | 4 × 5 × 3 in | 67 in | 0.41 cups | 1.00 cups | 259 g |
| Small | 5 × 6 × 4 in | 85 in | 0.52 cups | 1.25 cups | 324 g |
| Classic | 6 × 8 × 4 in | 100 in | 0.61 cups | 1.25 cups | 324 g |
| Large | 8 × 10 × 6 in | 136 in | 0.83 cups | 1.75 cups | 454 g |
| Showpiece | 10 × 12 × 7 in | 166 in | 1.02 cups | 2.25 cups | 583 g |
All houses have a 45° roof (50° for the showpiece), 1/4 in dough and a 1/2 in roof overhang. "Piped" is the estimate for the beads themselves. "Mix" is that doubled and rounded up to a quarter cup. This is for building only; decorating comes on top.
How the amount is worked out
Every joint gets a line of icing, so the amount follows the total seam length. For the 6 × 8 in classic, that is 100 in of seams, counted from the same piece sizes as the dimensions guide:
- The base: the four bottom edges of the walls.
- The four corners, counted twice because the assembly guide adds a second line down the inside of each one.
- The two sloped edges of each roof panel, where it meets a gable.
- The top edges of both side walls, under the roof panels.
- The ridge, where the two roof panels meet.
Multiply the seam length by the size of one bead. I assume a generous bead about 8 mm wide and 6 mm tall (38 mm² in cross-section, roughly the width of a pencil), and add 50% for icing that squeezes out of the joints, stays in the bag tip or dries in the bowl. Then the mix figure doubles the result, because thick icing is easier to pipe than to ration and a joint that runs short halfway through a wall is hard to fix. The bead size, the 50% and the doubling are my own assumptions, not measurements.
The sugar column assumes a recipe that behaves like Food Network Kitchen's: 2 pounds of confectioners' sugar (907 g) make 3 1/2 cups of icing, about 259 g of sugar per cup. Your recipe may differ, so scale it from your own yield.
What published recipes say
Food Network Kitchen's gingerbread doghouse (an 8 × 8 × 8 in house with a base) makes 3 1/2 cups of royal icing and says to thicken about 2 cups of it for building. My table gives 1.75 cups to mix for an 8 × 10 × 6 in house, a little under that 2 cups. The doghouse is a different shape and I read its 2 cups as the building share, so take this as a rough cross-check only.
SBS's gingerbread house recipe makes 2 egg whites and 3 cups of icing sugar and says that is enough for both mortaring and decorating one house. It does not give the house size, so treat it as a rule of thumb for a small house.
Adding the decorating
Decorating depends on you more than on the house, so it is not in the table. My suggestion: for a plain house with a few candies and a line of snow along the roof edge, mix as much again as the "Mix" column. For icicles, shingles or covering every wall, plan on double. A bigger batch costs little extra. Mixed icing hardens quickly in the open, so keep the bowl under a damp towel.
Metric: the 15 × 20 × 10 cm house has 251 cm of seams, about 143 ml piped and 300 ml (the "Mix" figure) to prepare.
Other sizes
The template generator shows the dough for any size you type, and the one-sheet guide lists small houses. A taller roof or a wider house adds seam length, so the numbers above grow with both.