How to Work Out Your Real Food Cost Per Plate (Free Method)

Here's a question I love asking café owners: what does your smashed avo actually cost you to make?

Most people give me a number straight away. But when you cost it properly, line by line, the real number can easily come out higher. Not because anyone was careless, but because the "quick maths" version usually leaves out the bits you throw away, the bits you give away and the bits that quietly went up in price last month.

I remember a smashed avo dish we ran on the specials menu. It was very, very popular. Unfortunately, it was nowhere near avocado season, so avocados were costing us about $2.50 each, and they weren't even good ones. Customers loved it, but we were losing money on every plate. So we killed it.

So let's fix that. Below is the method I use. All you need is a calculator, your supplier invoices and about 20 minutes per dish. No fancy software.

Why "food cost per plate" matters more than you think

Your food cost per plate is simply the total cost of the ingredients that go into one serve of a dish. Once you know it, you can work out your food cost percentage:

Food cost % = cost per plate ÷ selling price (excluding GST) × 100

That one number tells you whether a dish is pulling its weight. Without it, you're pricing on gut feel, and gut feel doesn't know that your eggs went up.

It also helps you make calmer decisions. Should you drop a dish? Change the portion? Push it harder on the specials board? It's much easier to answer when you can see the numbers.

Step 1: List every ingredient, including the boring ones

Write down everything that goes on the plate. And I mean everything:

The main ingredients (bread, eggs, avocado, feta)
The garnish (micro herbs, a lemon wedge, a sprinkle of dukkah)
The cooking fat (that splash of oil or knob of butter)
Sauces and dressings
Anything served on the side (a small pot of relish, a sachet of butter)

The boring ones are where the money hides. A garnish might only be a few cents, but on a dish you sell every day, those cents add up across a year.

Step 2: Find the purchase price and purchase unit

Grab your latest supplier invoices, not the price you remember from last year. For each ingredient, note:

What you paid (excluding GST, if you're registered for GST and claim it back)
The unit you bought it in (a 5 kg bag, a tray of 15 eggs, a 2 L bottle)

Then work out the cost per usable unit, usually per gram, per millilitre or per item.

For example: if a 1 kg block of feta cost you $X, then each gram costs $X ÷ 1,000.

Step 3: Adjust for yield and waste (the step most people skip)

This is the big one. You don't use 100% of what you buy.

Avocados have skin and a stone. Pumpkin has peel and seeds. A whole fish has bones and a head. Herbs wilt. Bread has crusts that end up in the bin. The part you can actually use is called the yield.

To find it, do a quick yield test:

Weigh the ingredient as you bought it.
Prep it the way your kitchen normally does.
Weigh the usable part.
Yield % = usable weight ÷ purchased weight × 100.

Then adjust your cost:

Real cost per usable gram = purchase cost per gram ÷ yield %

For example (example numbers only): say you buy avocados and a yield test shows that 65% of the weight is usable flesh. If the purchase cost works out to 2 cents per gram, the real cost of the flesh is 2 ÷ 0.65 ≈ 3.1 cents per gram. That's over 50% more than the "quick maths" number.

Do your yield tests on a normal day with your normal staff, not on a day when your most careful chef is prepping. You want the real yield, not the best possible yield.

My favourite waste story: we'd been slow-cooking a stock on the cooktop for over a day. I asked a new kitchen hand to strain it and throw away the bones and vegetables. He strained it, poured the stock down the drain and carefully kept the bones and veggies. Two days of work gone in seconds. Yield isn't just about the produce, it's about the people handling it too.

Step 4: Weigh the actual portion

Now weigh what actually goes on the plate. Not what the recipe card says. What your team really serves on a busy Saturday.

Make the dish three times (or watch it being made) and weigh each component. Use the average. If the recipe says 120 g of avocado and your team is serving 150 g, you'll want to know that.

Step 5: Add it all up

For each ingredient:

Ingredient cost = portion weight × real cost per usable unit

Add every ingredient together and you've got your cost per plate.

A worked example: smashed avo on toast

Let's put it all together. These are example numbers only, made up to show the method. Please plug in your own prices from your own invoices.

Ingredient	Portion	Real cost per unit (example)	Cost (example)
Sourdough (2 slices)	2 slices	$0.40 per slice	$0.80
Avocado (flesh, yield-adjusted)	120 g	3.1c per g	$3.72
Feta	30 g	2c per g	$0.60
Lemon wedge	1	$0.15	$0.15
Olive oil	10 ml	2c per ml	$0.20
Dukkah	5 g	4c per g	$0.20
Micro herbs	3 g	10c per g	$0.30
Total cost per plate			$5.97

Now say (again, as an example) the dish sells for $22.00 including GST. Take GST out first: $22.00 ÷ 1.1 = $20.00.

Food cost % = $5.97 ÷ $20.00 × 100 ≈ 29.9%

Notice what the avocado did. If you'd skipped the yield step and used 2 cents per gram, you'd have costed it at $2.40 and thought the plate cost about $4.65. That's a big gap on one dish, and it's exactly the kind of gap that eats margin without anyone noticing.

Step 6: Decide what "good" looks like for your café

There's no single magic food cost percentage that suits everyone. Your target depends on your rent, your wages, your style of service and what your customers expect to pay. The useful thing is to set a target for your business, then compare every dish against it.

When a dish is over your target, you've got options:

Adjust the portion (often the protein or the most expensive ingredient)
Swap an ingredient for something similar that costs less or has a better yield
Change the price
Keep it as it is, if it drives other sales (a great coffee-and-cake combo might be worth it)

The point isn't to make every dish perfect. It's to make your choices on purpose.

Common mistakes I see all the time

1. Using old prices. Supplier prices move. If you costed your menu once two years ago, it's time to redo it. Re-check your top sellers whenever a big invoice changes.

2. Forgetting yield. As the example shows, this alone can throw a dish out badly.

3. Ignoring the "free" bits. Bread and butter, the little biscuit on the saucer, sauce refills. Free to the customer isn't free to you.

4. Including GST in the selling price. If you're GST registered, divide the menu price by 1.1 before you calculate your percentage, or every dish will look better than it is.

5. Costing the recipe card instead of the real plate. Portions drift, especially when you're busy or have new staff. Weigh what's actually served.

6. Doing it once and never again. Costing isn't a one-off project. Pick a rhythm, like monthly for your top ten dishes, and stick to it.

My tip: measuring is very, very important. Get a scale and weigh every single portion until it's in your blood.

Keep it consistent with simple SOPs

Your costing is only accurate if every serve looks the same. That's where a simple standard operating procedure (SOP) helps: a one-page card per dish with the portion weights, the plating photo and the steps. New staff learn faster, and your numbers stay true.

If you'd rather not build all this from scratch, I put together a Café Profit Kit. It's a ready-made costing workbook that does the yield and margin maths for you, plus two editable SOP templates. But honestly, the method above works with a pen and paper too. The important thing is that you start.

Your 20-minute action plan

Pick your three best-selling dishes.
Pull your latest invoices.
Do a yield test on the trickiest ingredient in each.
Weigh a real portion.
Work out the cost per plate and food cost %.
Compare against your target and decide on one change.

That's it. Three dishes this week, three more next week, and in a month you'll know your menu better than ever.

FAQ

How often should I recalculate my food cost per plate? Whenever a key ingredient's price changes noticeably, and at least every month or two for your best sellers. Your top dishes have the biggest effect on your profit, so start there.

Should I include labour in food cost? No. Food cost per plate is ingredients only. Labour and overheads are tracked separately, so you can see each cost clearly. You'll look at them together when you set prices.

What if my ingredient yield changes from batch to batch? That's normal with fresh produce. Do a few yield tests over a couple of weeks and use the average. If one supplier's produce consistently yields less, that's useful information when you compare suppliers.