THE METHOD, MADE CLEAR
A recipe’s share
of the grocery bill.
Batchcost assigns ingredient costs to the amounts used in one recipe. It also shows the separate whole-pack checkout amount if you begin with none of those ingredients in stock.
Start with your own pack prices
Each row needs an ingredient name, the amount used in the recipe, that amount’s unit, the quantity in one purchased pack, the pack’s unit, and the price for one pack. Enter the price you actually want to use. The calculator does not fetch supermarket listings, predict discounts or choose a current market price.
Use one currency throughout a plan. The currency selector labels the amounts only; it does not apply an exchange rate. Use a consistent price basis for your own comparison. The tool performs no tax calculation and does not decide what should or should not be included in a business record.
The cost allocation formula
First express the recipe amount and pack amount in compatible units. Divide the amount used by the pack quantity, then multiply by the pack price. That assigns a proportional share of the purchase price to the recipe.
Pack share = recipe amount ÷ pack amount, after compatible-unit conversion
Ingredient cost used = pack share × price for one pack
Assigned batch cost = sum of ingredient costs used + other batch costs entered
Worked example: flour
A 1 kg pack costs an illustrative A$2.00. A recipe uses 300 g. The pack contains 1,000 g, so the recipe uses 300 ÷ 1,000 = 0.3 of the pack. The allocated flour cost is 0.3 × A$2.00 = A$0.60.
If you begin without flour, you still need to buy one whole pack for A$2.00. The unused 700 g has not disappeared; it remains available for another use.
What units can be compared?
The mass family contains grams and kilograms, using exactly 1,000 g per kg. The volume family contains millilitres and litres, using exactly 1,000 mL per L. The item family contains counts, such as the number of eggs, sachets or individual decorations. A row’s recipe and pack units must belong to the same family.
The tool deliberately rejects a recipe in grams paired with a pack in millilitres. Converting between mass and volume needs an appropriate density for that ingredient, and there is no universal cups-to-grams conversion. If your recipe uses cups or spoon measures, obtain a suitable measured or verified quantity in one of the supported units before entering it. For item counts, make sure the counted units are comparable; “one egg” does not tell the tool its size.
Fractions and decimal quantities
Recipe and pack quantities accept decimals such as 0.5, fractions such as 3/4, and mixed numbers such as 1 1/2. Common fraction characters, including ½, are accepted too. A pack described as “six 100 g sachets” can be entered as 600 g if the recipe uses grams, or six items if the recipe uses comparable sachets. Keep the interpretation consistent within that row.
A price of zero is allowed for a genuinely free ingredient or an intentional zero-price comparison. A quantity of zero is rejected; remove a row instead of leaving an unused ingredient in the plan. Empty or incompatible rows clear the previous result until corrected.
Whole-pack buying is a different number
The shopping calculation assumes zero stock and whole packs only. Required packs equal the recipe amount divided by the pack amount, rounded upward. One exact pack stays one pack; 1.01 packs requires two. Each ingredient is treated as a separate purchase row. If the same pack supplies two recipe ingredients, combine the relevant quantities in one row yourself to avoid counting the same purchase twice.
Whole packs required = ceiling(recipe amount ÷ pack amount)
Whole-pack ingredient checkout = sum of whole packs × pack price
Worked example: one small batch
The recipe uses 300 g of flour from the A$2.00, 1 kg pack; two eggs from a A$6.00 pack of 12; and 125 g of butter from a A$4.00, 250 g pack. Allocated costs are A$0.60, A$1.00 and A$2.00, totalling A$3.60.
With an entered A$0.50 of other batch costs, the assigned batch cost is A$4.10. For eight equal portions, the underlying cost per portion is A$0.5125, displayed as A$0.51. Buying the three ingredient packs from zero stock costs A$12.00, excluding the separate other-cost figure.
Other batch costs and portions
The optional other-cost figure is a single amount you supply. It can represent whatever known batch costs you intend to include, but the calculator does not estimate them or judge whether the figure is complete. Leave it at zero when you want ingredients only. Divide the assigned total by the number of equal portions for a per-portion allocation.
This result is not revenue, margin, profit, a sale price or a claim that a food product is commercially viable. No labour, equipment, spoilage, packaging, energy, delivery or other costs are included unless they are represented in your own entered figures. The whole-pack checkout total always covers ingredient packs only.
Reading and keeping the numbers
Currency results normally show two decimal places. Very small positive costs keep extra significant digits so they are not shown as zero. Calculations retain their underlying values until display; adding several rounded row displays can differ slightly from the rounded total. CSV export includes the underlying ingredient allocations, pack counts, checkout amounts and per-portion cost.
Copy and download work in your browser. Ingredient names are treated as text, and CSV text beginning with spreadsheet formula characters is neutralised. Nothing in the recipe is sent to the operator by the calculator.