Variable cost ratio: the simplest number that tells you how strong your unit economics are.

Variable cost ratio is total variable cost divided by total revenue, expressed as a percentage. A café with €1,000 of net revenue and €280 of variable cost has a variable cost ratio of 28%. The other 72% is contribution margin — the money available to cover fixed costs and become profit.

What it means

Variable cost ratio is the share of every euro of revenue that gets eaten by costs scaling directly with the sale. COGS (the milk, the wholesale stock, the colour at a salon). Packaging. The card fee on each transaction. Shipping for e-commerce. Anything that goes up when you sell one more unit, and down when you sell one fewer.

It is the mirror image of contribution margin %. If your contribution margin is 72%, your variable cost ratio is 28%. They always add to 100%. Tracking either one tracks both — but variable cost ratio is the more intuitive number when you are diagnosing a creeping problem ("my ingredient cost has gone up") because it shows the deduction directly rather than the leftover.

The denominator is net revenue, not gross. The gross-vs-net revenue post walks through why every ratio in your P&L should be computed on net — using gross inflates revenue by the VAT amount and makes every cost ratio look 15-25% better than reality.

How to calculate it

Variable cost ratio = Total variable cost ÷ Net revenue × 100

Variable cost includes:
  COGS (snapshotted at sale)
  Packaging / consumables that scale with each sale
  Card fees (variable component)
  Shipping (e-commerce)

In nouz, the variable cost ratio for any day, week or month is computed automatically from the daily entries. COGS is snapshotted on every product sale, variable costs are logged at close, card fees are computed from the cash/card split. Divide the sum by net revenue and you have the ratio.

Worked example

A café month: €18,000 of net revenue. Variable costs add up as below.

32.8% of every euro of revenue goes to variable costs. The remaining 67.2% is what is left to cover fixed costs (rent, salaries, insurance, software) and become profit. If the café's fixed costs are €5,500/month, profit on this month is €18,000 × 67.2% − €5,500 = €12,096 − €5,500 = €6,596.

Now imagine milk prices rise and ingredient COGS climbs from €5,200 to €5,900 next month. Variable cost ratio jumps from 32.8% to 36.7%. The same fixed costs are still €5,500. Profit on the same €18,000 of revenue falls to €18,000 × 63.3% − €5,500 = €11,394 − €5,500 = €5,894. A 4-point increase in variable cost ratio cost €702 of profit. The variable cost ratio is the early-warning sign that costs are creeping; without it the owner only notices when the bank balance does at month-end.

What is a healthy variable cost ratio?

Healthy ranges by sector — these are the mirror image of contribution margin benchmarks:

Salons sit at the bottom because product cost is a thin layer on top of stylist labour (which is a fixed cost). E-commerce sits at the top because shipping and packaging act like variable costs on every order. If your ratio drifts above the top of your sector's range, the cause is almost always one of: supplier price rises that menu prices have not absorbed, a card fee rate negotiated years ago that is now uncompetitive, or shipping costs that have outgrown the unit price.

Why it matters

Variable cost ratio is the cleanest single signal of whether your unit economics are getting better or worse. Track it monthly; track it daily if your COGS swings (food businesses, e-commerce). A creeping ratio is the earliest sign that you need to raise prices, renegotiate with a supplier, or change the product mix. Owners who watch it catch the problem when it is a one-point drift; owners who do not catch it when it is a five-point hole.

Related concepts

• Fixed vs variable costs — the split that makes the ratio meaningful.
• Break-even analysis — uses contribution margin (1 − variable cost ratio) to find your break-even point.
• EBIT explained — variable cost is one of the deductions on the way from net revenue to EBIT.

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