How much fondant to cover a cake
Enter the cake and the overhang, and get the fondant to weigh out and how wide to roll it.
Free. No signup needed.The short answer
An 8 inch (20cm) round about 4 inches tall takes roughly 750 g of fondant rolled to 5 mm, and needs rolling out to about an 18 inch circle. A 6 inch takes about 500 g and a 10 inch about 1 kg. Enter your cake below for the exact weight.
How much fondant to cover a cake
BakerInbox
The cake to cover
Fondant to roll out
738 g
Top and sides at 5 mm, about 26 oz
Roll it out to
18 in (46 cm)
Diameter, to drape and trim
What it costs
Fondant cost
£4.43
At your price per kg
Worked from the surface the fondant has to cover, the top plus the sides, at a steady 5 mm, so a taller or wider cake gets its own answer. Roll to the size above so the sheet reaches the board, then trim once the cake is covered. Warm the fondant soft before you roll.
The fondant is the last layer. BakerInbox keeps your recipes, prices, and orders in one place.
Start free trialFondant to cover, and how wide to roll
| Cake size | Round (g) | Round (oz) | Square (g) | Square (oz) |
|---|---|---|---|---|
| 6 in | 508 g1 lb 2 oz | 18 oz | 703 g1 lb 9 oz | 25 oz |
| 7 in | 619 g1 lb 6 oz | 22 oz | 857 g1 lb 14 oz | 30 oz |
| 8 in | 738 g1 lb 10 oz | 26 oz | 1.02 kg2 lb 4 oz | 36 oz |
| 9 in | 865 g1 lb 15 oz | 31 oz | 1.20 kg2 lb 10 oz | 42 oz |
| 10 in | 1.00 kg2 lb 3 oz | 35 oz | 1.38 kg3 lb 1 oz | 49 oz |
| 12 in | 1.29 kg2 lb 14 oz | 46 oz | 1.79 kg3 lb 15 oz | 63 oz |
A guide for an all-in-one cover at 5 mm. A taller cake, thicker roll, or covered board takes more.
How wide to roll it
| Cake size | Round, roll to | Square, roll each side to |
|---|---|---|
| 6 in | 16 in (41 cm) | 16 in (41 cm) |
| 7 in | 17 in (43 cm) | 17 in (43 cm) |
| 8 in | 18 in (46 cm) | 18 in (46 cm) |
| 9 in | 19 in (48 cm) | 19 in (48 cm) |
| 10 in | 20 in (51 cm) | 20 in (51 cm) |
| 12 in | 22 in (56 cm) | 22 in (56 cm) |
The cake plus twice its height, plus an inch each side to grip and trim. A taller cake needs a wider sheet.
Made with BakerInbox. Free cake tools at bakerinbox.com/tools
How much fondant to cover a cake
Fondant to cover a cake is worked from the surface it has to reach: the top, the sides, and a little overhang to grip and trim. An 8 in round about 4 in tall takes roughly 750 g rolled to 5 mm. Enter your cake and the calculator works the weight, the roll-out size, and the cost.
The surface
It comes from the surface, not the servings
The fondant a cake takes is set by the surface it has to cover, the top plus the sides, not by how many people it feeds. A taller cake has deeper sides, so it takes more even at the same width. A 10 in round has nearly twice the surface of a 6 in, so it takes nearly twice the fondant. This tool works that area for you and turns it into a weight at a standard 5 mm roll.
Roll it bigger
Roll to the cake, plus twice the height
A single sheet has to drape the top and reach down both sides, so it must be rolled to the cake width plus twice the height, plus a margin to grip and trim. For an 8 in round about 4 in tall that is roughly an 18 in circle. The calculator gives you the exact roll-out size so you cut the fondant once and it reaches the board.
Thickness
About 5 mm, the same every time
Rolled fondant is worked to about 5 mm, thick enough to hide the ganache and take a smooth finish without tearing. Roll it thinner and you use less but risk seams and elephant skin. The weights here assume a steady 5 mm, so the number holds as long as you roll to guides rather than by eye.
Practical
Warm it, and give yourself an inch
Cold fondant cracks, so knead it soft before you roll. Leave about an inch of overhang all round: enough to smooth the top edge and ease the sides down without running short at the base. Trim once the cake is covered. Keep the offcuts sealed and they colour up for decorations.
Sugarpaste and marzipan
Same weights, different names
Fondant and sugarpaste are the same thing in UK shops, so these weights apply whichever the packet says. Marzipan is not: it rolls thicker, usually 5 mm over a layer of apricot jam, and it goes under the icing rather than over the ganache. For a fruit cake that needs both, the Christmas cake calculator works out the marzipan and royal icing together with the fruit. Under fondant on a sponge, you want a firm ganache instead.
FAQ
Common questions
How much fondant do I need to cover a cake?
It depends on the surface, not the servings. A standard 8 in round about 4 in tall takes roughly 750 g rolled to 5 mm, a 6 in round about 500 g, a 10 in round about 1 kg. A square takes more than a round of the same size because of the corners. Enter your cake above and the calculator works it exactly.
How much fondant to cover an 8 inch cake?
About 750 g for an 8 in round roughly 4 in tall, rolled to 5 mm. Roll it thinner and you use a little less. An 8 in square takes more, around 1 kg, because the corners add surface and waste. A taller cake takes more again.
How thick should fondant be rolled to cover a cake?
About 5 mm. That is thick enough to hide the ganache underneath and hold a smooth finish without tearing on the edges. Rolled thinner, around 3 to 4 mm, you use less but risk seams showing and the surface creasing. The weights here assume 5 mm, rolled to guides rather than by eye.
How big should I roll the fondant out?
Wide enough to cover the top and drape both sides, so the cake width plus twice the height, plus about an inch each side to grip and trim. For an 8 in round about 4 in tall that is roughly an 18 in circle. The calculator gives you the roll-out size along with the weight.
How much fondant for a square cake?
More than a round of the same size. A square has a larger top and deeper corners, and the corners waste a little as you ease the fondant down, so an 8 in square takes about 1 kg against roughly 750 g for an 8 in round. Enter the shape above and the calculator adjusts for it.
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