How to calculate waste and what it costs you

What counts as waste in a shop?

Waste is the part of what you bought or made that leaves your hands without being sold: thrown away, spoiled, broken, cut off, or never made in the first place. You've paid for it, but it will never reach the till.

It looks different in every trade. Profiteroles that go stale in a patisserie, loaves left over at a bakery, roots and stalks trimmed off vegetables in a restaurant kitchen, offcuts on a textile studio's cutting table, a mug that comes out of the kiln cracked. One at a time they look small; added up over a month they're real money.

Sorting waste by type makes it easier to fix, because each type has a different cause. Spoiled milk is an ordering problem, offcuts are a pattern-layout problem, and a short batch is a recipe or technique problem.

How do you calculate your waste rate?

Divide the quantity wasted by the quantity used or made, then multiply by 100. For raw materials divide by what you used, for things you make divide by how many you made, and for goods you buy in and resell divide by how many you bought.

Three quick examples. A grocer buys 40 cartons of milk this week and 4 go past their date: 4 ÷ 40 × 100 = 10%. A bakery makes 200 loaves today and 12 are left in the evening: 12 ÷ 200 × 100 = 6%. A restaurant trims 5 kg of spinach and 1.2 kg goes in the bin: 1.2 ÷ 5 × 100 = 24%.

The rate lets you compare days and products of different sizes, but on its own it misleads. That 24% spinach waste is worth ₺72.00 at ₺60.00 per kg. The 6% bread waste, on 12 loaves that cost ₺15.00 each, is ₺180.00. A small rate can be a big number, so always put the money next to the percentage.

Why value waste at cost and not at selling price?

Because the money you lose on something you throw away is the money you paid for it. The profit built into the selling price never reached your till; add it to the loss and the loss looks bigger than it is.

Say a portion of profiteroles costs you ₺45.00 to make and sells for ₺120.00. If 4 portions are thrown away at the end of the day, the loss is 4 × ₺45.00 = ₺180.00. At the selling price it would come to ₺480.00; the extra ₺300.00 is profit you never made, not money that left your pocket.

Lost sales are a separate problem. A customer who leaves empty-handed because the profiteroles ran out really is lost profit, but that comes from making too few, not from making too many and binning them. Value waste at cost, think about lost sales separately, and don't add the two into one number.

How do you calculate waste in a patisserie, a kitchen and a textile studio?

The same two formulas work in all three; only the unit changes: portions in the patisserie, kilos in the kitchen, metres in the textile studio.

Patisserie: profiteroles that went stale

16.7% may not sound like much. But if it happens every Tuesday, that's 4 × ₺180.00 = ₺720.00 a month across four Tuesdays. In a patisserie, the fix for end-of-day waste is usually in the quantity, not the recipe; more on that below.

Restaurant: vegetables lost in trimming

In a restaurant kitchen, the waste nobody notices isn't on returned plates but on the prep counter. You buy 5 kg of spinach at ₺60.00 per kg for ₺300.00; once the roots and yellow leaves are gone, 3.8 kg of clean spinach is left.

• Trim waste: 5 − 3.8 = 1.2 kg; 1.2 ÷ 5 × 100 = 24%.
• Cost of the waste: 1.2 × ₺60.00 = ₺72.00.
• Real cost of clean spinach: ₺300.00 ÷ 3.8 = ₺78.95 per kg (rounded).

The last line matters most. If your recipe uses 200 g of clean spinach per plate and you cost it at ₺60.00 per kg, the plate comes out at ₺12.00; in reality it's 0.2 × ₺78.95 = ₺15.79. If the trim is roughly the same every time, put the untrimmed quantity in the recipe (about 263 g for 200 g clean) and both cost and stock come out right. Then don't also enter the trimmings as waste, or you'll count them twice.

Textiles: fabric lost in cutting

In a textile studio, waste is measured in metres. You bought a 40-metre bolt of linen for ₺8,800.00, so a metre costs ₺8,800 ÷ 40 = ₺220.00. This week you cut 30 m from the bolt, and 2.5 m was left as scraps too small to use.

• Cutting waste: 2.5 ÷ 30 × 100 = 8.3% (rounded).
• Cost of the waste: 2.5 × ₺220.00 = ₺550.00.

If some of the leftover goes into linings, covered buttons or a small pouch, that part isn't waste; it's material for another product. Record only what really gets thrown away. Laying the pattern pieces closer together on the fabric is the most direct way to bring this rate down.

Why is a short batch hidden waste?

Because nothing gets thrown away, nobody writes it down, yet the cost of the same ingredients is spread over fewer pieces. If ingredients for 10 cheesecakes make only 9, the cost of the missing tenth lands on the other nine.

Say the ingredients for a batch of pistachio cheesecakes cost ₺560.00. With 10 expected, each costs ₺560 ÷ 10 = ₺56.00. With 9 made, each costs ₺560 ÷ 9 = ₺62.22. That ₺6.22 is an 11.1% rise in cost per piece, and if you haven't changed the price, it comes straight out of your profit.

In ceramics the same sum bites harder. Twenty mugs go into the kiln and 17 come out whole: 85% yield. If each mug was planned to cost ₺89.00, the three missing mugs are worth 3 × ₺89.00 = ₺267.00. If that loss never makes it into your selling price, every firing takes that much off the profit you think you're making.

Where does unrecorded waste go?

Nowhere; it turns up at your next stock count as a gap you can't explain. If your records say there should be 6 L of cream in the fridge and you count 4.5 L, some of that 1.5 L is very likely cream that split, spilled or was thrown away without anyone writing it down.

That's why recording waste and counting stock check each other. In a shop that records waste regularly, count gaps stay small, and when a big one appears there are fewer places to look. We explain how to read the gap step by step in how to do a stock count.

One habit worth picking up: don't try to remember waste in the evening; write it down the moment you throw something away. What comes to mind at the end of the day is only part of what happened.

How do you reduce waste?

Measure it first, then fix one item a week. These four habits are the easiest to put into practice in a small shop.

Make quantities from the sales average

Decide how many to make today from the average for the same weekday over the last few weeks, not from yesterday's sales. If you sold 18, 21, 19 and 22 portions of profiteroles on the last four Tuesdays, the average is (18 + 21 + 19 + 22) ÷ 4 = 20. Making 20 or 21 on a Tuesday instead of 24 cuts out most of those 4 wasted portions. The same sum works for leftover loaves in a bakery: note how many are left each day for a month, then size the dough to the day.

Stock shelves first in, first out

New deliveries go to the back, older stock to the front. Milk, cream, vegetables, meat: what's closest to its date gets used first, and less of it goes past. A small label with the delivery date on each container is often all it takes to keep the order.

Measure portions instead of guessing

Ladles, scales, measuring spoons. An over-generous portion doesn't go in the bin, but it does leave your stock; it never shows up as waste, only later as a count gap. What goes on the plate should match the recipe; if it doesn't, fix either the measure or the recipe.

Each week, pick the one item that lost you the most

Look at the week's waste total, pick the item with the biggest value and spend a week on that alone. Make fewer? Order smaller amounts more often? Store it differently? Next week, check the same item's number again. Really fixing one item usually pays more than nudging ten.

How do you track waste, step by step?

Waste tracking comes down to six steps: write it down at once, sort it by type, find the unit cost, work out the value and the rate, total it each week and fix the biggest item.

1. 1Write it down at onceNote what you threw away, how much, and in what unit: 4 portions of profiteroles, 1.2 kg of spinach, 2.5 m of linen. Waste left for the end of the day gets forgotten.
2. 2Sort it by typeSpoiled, left over, cutting waste or a short batch? Knowing the type is half of finding the cause.
3. 3Find the unit costFor raw materials, divide the last purchase total by the quantity; for things you make, use the cost per piece from the recipe.
4. 4Work out the value and the rateValue = quantity wasted × unit cost. Rate = quantity wasted ÷ quantity used or made × 100.
5. 5Total it each weekAt the end of the week, add up waste per item and sort by value; the item at the top is this week's job.
6. 6Change one thing, then compareFor the biggest item, change one thing: the quantity, how often you order, or how you store it. A week later, check that item's value again.