Wedding Cake Quantity Calculator
Calculate Your Wedding Cake Needs
Enter your guest count and dietary restrictions to get an accurate cake weight estimate.
Recommended Cake Quantity
*Based on industry-standard 2"x2" slices and 100 guests
How We Calculated This
- Base calculation: 1.3 lb per guest (100 guests × 1.3)
- Added 5% for dietary restrictions
- Adjustments for buttercream frosting (standard)
When you’re planning a wedding for 100 guests, the biggest question after the dress and venue is usually… how much cake do you actually need? Too little and you’ll have empty plates; too much and you’ll be cutting into the dessert budget.
Wedding cake is the centerpiece of most reception dessert tables, and getting the right amount is a mix of math, tradition, and a few practical tweaks. Below is a step‑by‑step guide that takes you from raw guest numbers to the perfect slice for every palate.
1. Start with the basic serving math
Most bakers use two simple rules of thumb:
- One pound of cake feeds about 8-10 guests.
- One standard slice (about 2" × 2") serves one person.
For 100 guests, the pound‑per‑guest rule gives you a range of 10-13 pounds of cake. The slice rule says you need roughly 100 slices, which translates to about 12-14 pounds depending on the density of the frosting.
2. Factor in tiered‑cake geometry
Most wedding cakes are tiered. Each tier is a cylinder, and the total weight depends on its diameter, height, and the number of layers per tier. A quick way to estimate:
- Choose your tier sizes - a common set for 100 guests is 12", 10" and 8" diameters.
- Assume each tier is 4" tall (two 2" layers).
- Calculate the volume of each tier:
π × (diameter/2)² × height
. - Multiply the volume by the cake’s average density (≈0.5 lb per cubic inch for a standard buttercream cake).
Using those numbers, the 12" tier weighs about 6 lb, the 10" tier 4.5 lb, and the 8" tier 3 lb - total roughly 13.5 lb, right in the sweet spot.
3. Adjust for flavor and filling choices
Heavier fillings like fruit curd or ganache add about 0.2 lb per slice, while lighter options such as whipped cream add almost nothing. If you plan a mixed‑flavor cake (e.g., vanilla with chocolate ganache), add an extra 1 lb to cover the denser sections.

4. Account for dietary restrictions
It’s common to reserve 5-10 % of the total cake for guests with special diets. For 100 guests, set aside 5-10 slices for gluten‑free, vegan, or nut‑free versions. In practice, that means adding another half‑pound to the overall weight.
5. Use practical tools and checklist
Below is a quick checklist you can run through with your baker:
- Confirm total guest count (include children who might need smaller portions).
- Decide on tier sizes and height.
- Choose flavors, fillings, and frosting type (see related entities).
- Calculate base weight using the pound‑per‑guest rule.
- Add 5 % for dietary‑restriction slices.
- Round up to the nearest half‑pound for safety.
- Ask the baker for a sample slice and adjust if it feels too dense or too light.
6. Sample calculations for 100 guests
Let’s walk through three common methods using the same guest count.
Method | Approx. cake needed | Pros | Cons |
---|---|---|---|
Weight‑per‑guest (8‑10 guests per pound) | 12 lb | Simple, works for any frosting | Ignores tier shape, may over‑ or under‑estimate |
Slice‑per‑guest (1 slice = 2"×2") | 13 lb | Matches plate size, easy to visualise | Depends on slice density, frosting weight |
Tiered‑cake geometry | 13.5 lb (12"+10"+8" tiers) | Accurate for visual planning, fits décor | Requires measurements, more math |
All three methods land between 12 lb and 14 lb. If you want a safety net, order 14 lb - that gives you roughly 100 full slices plus a few extra for late‑arriving guests or those who want seconds.

7. Pro tips from seasoned bakers
- Use a cake slicer with a guide rail. It ensures each guest gets the same portion and prevents early depletion of the top tier.
- Ask for Buttercream rather than heavy fondant if you expect a lot of guests; buttercream stays moist and is easier to cut.
- Keep a small “reserve” cake (about 1 lb) in the kitchen for any unexpected guests or mishaps.
- When using multiple flavors, stagger them across tiers so each tier has a consistent weight.
Quick checklist for ordering
- Guest count: 100 (plus 5 % for dietary needs).
- Base weight: 12‑13 lb (using pound‑per‑guest rule).
- Tier plan: 12"‑10"‑8" tiers, 4" tall each.
- Flavor/filler: decide on any heavy ganache or light whipped cream.
- Extra: add 0.5‑1 lb for dietary slices and safety.
- Round up to nearest half‑pound → 14 lb total.
- Confirm with baker, request a slice sample, and lock in the final order.
Frequently Asked Questions
How many tiers are typical for 100 guests?
Three tiers (usually 12", 10" and 8" diameters) comfortably serve 100 guests, giving enough surface area for decoration while keeping the cake manageable.
Can I substitute fondant for buttercream and still meet the weight estimate?
Yes, but fondant is denser. Add roughly 0.2 lb per 10 slices to the base weight. For 100 guests, that’s about an extra 2 lb, so order 15 lb if you go full fondant.
What’s the best way to handle gluten‑free guests?
Bake a separate gluten‑free mini‑tier (about 0.5 lb) or reserve 5‑10 slices made with almond‑flour cake. Keep it clearly labeled to avoid cross‑contamination.
Do I need a larger cake if the reception is outdoors?
Outdoor heat can dry out buttercream faster, so a slightly bigger cake (add 0.5 lb) ensures you have enough moist slices even if some spoil.
Is a 2" × 2" slice too small for a wedding cake?
It’s the industry standard because it balances portion size with the number of guests. If you want larger slices, simply increase the total cake weight by 10‑15 %.