To find out how many products you can make, divide the amount you have of each material by the amount one product uses, round each result down to a whole number, and take the smallest result. The material that gives the smallest number is your limiting material, and that number is the most you can make.
Capacity = the smallest of (quantity on hand ÷ quantity per unit), rounded down
This sounds obvious, but it is easy to get wrong when units differ, when several products share a material, or when you forget packaging. The examples below show each case with real numbers.
Step 1: List what one unit uses
Start from the recipe (also called a bill of materials). Write down every material that is consumed by making one sellable unit, including packaging. If your recipe is written per batch, divide by the number of units the batch makes. If you are new to the idea, read what a recipe or BOM is.
Example: one 9 oz candle uses:
- 180 g of wax
- 12 g of fragrance oil
- 1 wick
- 1 jar
- 1 label
Step 2: Write down what you have, in the same units
Quantities must be in the same unit as the recipe before you divide. Convert first. The international avoirdupois pound is defined as exactly 453.59237 grams, so a 10 lb box of wax is 10 × 453.59237 = 4,535.92 g, and one ounce is 28.349523125 g.
Example stock:
- Wax: 4,500 g
- Fragrance oil: 330 g
- Wicks: 70
- Jars: 58
- Labels: 120
Step 3: Divide, round down, and take the smallest
For each material, divide what you have by what one unit uses:
- Wax: 4,500 ÷ 180 = 25
- Fragrance oil: 330 ÷ 12 = 27.5, which rounds down to 27
- Wicks: 70 ÷ 1 = 70
- Jars: 58 ÷ 1 = 58
- Labels: 120 ÷ 1 = 120
The smallest is 25, so you can make 25 candles, and wax is the limiting material. Always round down: half a candle is not a product, and 27.5 candles' worth of fragrance still only makes 27.
After making 25 candles you would have 0 g of wax, 30 g of fragrance oil, 45 wicks, 33 jars and 95 labels left. Those leftovers matter: only 30 g of fragrance oil is left, enough for 2 more candles (30 ÷ 12 = 2.5, rounded down), so reordering wax alone would raise your capacity by just 2 until you also buy fragrance oil. Once one material is restocked, the next one becomes the limit.
If your wax came as a 10 lb box instead of grams, the same sum is 4,535.92 ÷ 180 = 25.2, which still rounds down to 25.
Example 2: a recipe written per batch
Batch recipes need one extra step. A body butter recipe makes 10 jars per batch and uses 400 g of shea butter and 200 g of oil, plus one jar, lid and label per jar.
Per jar that is 40 g of shea butter and 20 g of oil. Stock: 2,000 g shea butter, 1,100 g oil, 38 jars, 40 lids and 100 labels.
- Shea butter: 2,000 ÷ 40 = 50 jars
- Oil: 1,100 ÷ 20 = 55 jars
- Jars: 38
- Lids: 40
- Labels: 100
You can make 38 jars if you can scale a batch to any size, and the jars are the limiting material. If you only ever make whole batches of 10, the answer is 30 jars (three batches), because 38 ÷ 10 = 3.8 rounds down to 3. Decide which of the two matches how you actually work.
Example 3: two products that share a material
This is where capacity numbers mislead. Say you also make a smaller 6 oz candle that uses 120 g of wax. On its own, the same 4,500 g of wax makes 4,500 ÷ 120 = 37 small candles (37.5 rounded down). On its own, it makes 25 large candles.
Those capacities overlap. You cannot make 25 large and 37 small, because both draw on the same wax. Check a combined plan instead:
- Plan: 20 large and 8 small candles.
- Wax needed: 20 × 180 + 8 × 120 = 3,600 + 960 = 4,560 g. You have 4,500 g, so you are 60 g short.
- Option A: 20 large and 7 small uses 3,600 + 840 = 4,440 g, leaving 60 g.
- Option B: 19 large and 9 small uses 3,420 + 1,080 = 4,500 g exactly.
Rule: when products share a material, add up what the whole plan needs from that material and compare the total with your stock. Do this for every shared material, not just the one that looks tight.
Step 4: Allow for real-world loss
Recipes describe the ideal. Real production loses some material to residue in pouring jugs, trimming, test pieces and spills. Measure your typical loss over a few batches and reduce your usable stock by that percentage.
With 4% loss on the wax in Example 1, usable wax is 4,500 × 0.96 = 4,320 g, and 4,320 ÷ 180 = 24 candles, not 25. Whether that one-candle difference matters depends on the size of your batches. For expensive materials, or when an order has a hard date, it is worth including.
Also subtract stock that is already spoken for. If 600 g of that wax is set aside for a confirmed order, your free wax is 3,900 g, which makes 21 candles (3,900 ÷ 180 = 21.7).
Step 5: If you cannot make enough, work out what to buy
Suppose you want 40 candles. For each material, multiply the per-unit amount by 40 and subtract your stock:
- Wax: 40 × 180 = 7,200 g needed, 4,500 g on hand, 2,700 g short (about 5.95 lb).
- Fragrance oil: 40 × 12 = 480 g needed, 330 g on hand, 150 g short.
- Wicks: 40 needed, 70 on hand, fine.
- Jars: 40 needed, 58 on hand, fine.
- Labels: 40 needed, 120 on hand, fine.
At illustrative prices of $12 per 1,000 g of wax and $20 per 100 g of fragrance oil, the shortfall costs 2,700 × $0.012 + 150 × $0.20 = $32.40 + $30.00 = $62.40. That is the amount you need to buy before you can make 40, and it tells you whether the order is worth taking. Add supplier lead time to find the date to place the order. For a seasonal example of working backward from ship dates, see the holiday production planning checklist, and for setting reorder levels see low stock alerts for handmade businesses.
Common mistakes
- Mixing units. Dividing 4,500 g by a recipe quantity in ounces gives nonsense. Convert first.
- Forgetting packaging. Jars, wicks, lids and labels limit production as often as ingredients do.
- Adding capacities together. Capacities per product overlap when materials are shared. Add up requirements instead.
- Not rounding down. Capacity is a whole number of sellable units.
- Using ideal yield. If a batch designed for 24 usually gives 22 sellable units, plan with 22.
- Using stock that is already committed. Subtract materials reserved for open orders.
How Loomenio calculates this for you
Doing this by hand for every product is slow, and it changes every time you receive a delivery or make a batch. In Loomenio, each product with a recipe shows how many units you can make from current stock and which material is the limit. Recipes convert between units of the same kind, so a pound of wax and a gram requirement work together. Enter a quantity and Loomenio shows which materials are short and what buying them would cost. Today then flags products that cannot be made and suggests materials to reorder, with the numbers behind each suggestion.
Capacity is shown per product, so when several products share a material, check the combined plan as in Example 3. Loomenio does not know your waste rate or your committed orders unless you reflect them in your stock and recipes.
If you want to check the cost side first, use the free product cost calculator. To see this workflow for your products, read about candle makers, soap makers and skincare makers, or look at the plans.
Frequently asked questions
How do I calculate how many products I can make?
For each material, divide the quantity you have by the quantity one unit uses and round down. The smallest result is the number you can make, and that material is your limiting material. Include packaging, and convert every quantity to the same unit before dividing.
What is the limiting material?
It is the material that runs out first when you make a product. In Example 1 it is wax, because 4,500 g covers 25 candles while the other materials cover 27 or more. Buying more of the limiting material is what raises your capacity, until the next material becomes the limit.
How do I calculate capacity when products share a material?
Do not add each product's separate capacity. Instead, decide how many of each you want, multiply by each product's requirement, add the totals for every shared material, and compare with your stock. If the total is higher than your stock, reduce one of the quantities.
Should I include waste in the calculation?
Yes, if you lose material in a predictable way. Measure the loss over several batches, then reduce usable stock by that percentage. For example, 4% loss turns 4,500 g of wax into 4,320 g of usable wax.
Can software calculate this automatically?
Yes. Software that links recipes to stock can recalculate capacity whenever stock changes. Loomenio shows how many units of each product you can make, which material is the limit, and what buying a shortfall would cost. It shows capacity per product, so check shared materials across a combined plan.