Fondant Needed
1.6 lbs
Weight
25.2 oz (713 g)
Roll-out Size
18.0" circle
Save $7.86 by making fondant at home
| Cake Size | 4" Tall | 6" Tall |
|---|---|---|
| 6" round | ~1.1 lb | ~1.5 lb |
| 8" round | ~1.6 lb | ~2.1 lb |
| 10" round | ~2.1 lb | ~2.8 lb |
| 12" round | ~2.8 lb | ~3.5 lb |
| 14" round | ~3.4 lb | ~4.4 lb |
Values at 3/16" thickness, full coverage, 10% margin
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An 8-inch round cake at 4 inches tall needs about 1.6 lbs of fondant rolled into an 18-inch circle. Homemade marshmallow fondant costs under $5 versus nearly $13 store-bought.
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A tall 10-inch square cake requires 3.5 lbs of fondant. The 24-inch roll-out size means you need a large work surface. This is where homemade fondant saves almost $18.
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A standard sheet cake with thin fondant and 20% extra for decorations needs about 2.2 lbs. The thin layer gives a sleek finish while the extra margin provides material for bows or cut-outs.
An 8-inch round cake that is 4 inches tall needs approximately 1.6 lbs (25 oz) of fondant at standard 3/16-inch thickness with full coverage. A taller 6-inch cake needs about 2.1 lbs. These amounts include a 10% margin for trimming and smoothing.
| Cake Size | 4" Tall | 6" Tall |
|---|---|---|
| 6" round | ~1.1 lb | ~1.5 lb |
| 8" round | ~1.6 lb | ~2.1 lb |
| 10" round | ~2.1 lb | ~2.8 lb |
| 12" round | ~2.8 lb | ~3.5 lb |
For a round cake, the top area equals π × (diameter/2)² and the side area equals π × diameter × height. For a square cake, the top is side × side and sides are 4 × side × height. Add 10–20% extra for trimming and draping margin.
Standard fondant thickness is 3/16 inch (about 5mm). Thin fondant at 1/8 inch (3mm) gives a sleek, modern look but tears more easily. Thick fondant at 1/4 inch (6mm) is sturdier and better for sculpted or 3D cake designs.
| Thickness | Best For | Difficulty |
|---|---|---|
| 1/8" (3mm) | Modern, smooth cakes | Advanced |
| 3/16" (5mm) | Wedding, birthday cakes | Intermediate |
| 1/4" (6mm) | Sculpted, 3D designs | Beginner |
Roll fondant into a circle (or rectangle) equal to the cake diameter plus twice the height plus 2 inches for draping excess. For an 8-inch round cake that is 4 inches tall, roll an 18-inch circle: 8 + (2 × 4) + 2 = 18 inches.
Homemade marshmallow fondant costs about $3 per pound, while commercial fondant costs $6–$10 per pound. For a typical 8-inch cake needing 1.5 lbs, homemade saves $5–$10. Homemade fondant also tastes significantly better than most commercial brands.
| Type | Cost/lb | 8" Cake Cost | Taste |
|---|---|---|---|
| Homemade | ~$3 | ~$4.70 | Excellent |
| Store Brand | ~$6 | ~$9.40 | Fair |
| Premium Brand | ~$8–$10 | ~$12.50 | Good |
Knead fondant until smooth and pliable before rolling. Apply a thin crumb coat of buttercream and chill it for 15–20 minutes. Roll fondant evenly from center outward on a cornstarch-dusted surface. Drape over the cake, smooth from top down, then trim excess.
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Last Updated: Oct 19, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.