Break-even Formula Explained: Fixed Costs, Variable Costs, and the Math

What Is the Break-even Point?

The break-even point is the level of sales at which total revenue equals total costs — you are neither making a profit nor incurring a loss. Every unit sold beyond this point generates profit; every unit below it means you are operating at a loss.

Break-even analysis is one of the most fundamental tools in business planning. It answers a critical question: How much do I need to sell to cover my costs?

The Formula

The denominator — Selling Price minus Variable Cost — is called the contribution margin per unit. It represents how much each unit sold contributes toward covering fixed costs.

Understanding the Components

Fixed Costs

Fixed costs stay the same regardless of how many units you produce or sell. Examples include rent, salaries, insurance premiums, loan payments, and software subscriptions. Even if you sell zero units, you still pay these costs.

Variable Costs

Variable costs change directly with production or sales volume. Examples include raw materials, packaging, shipping, payment processing fees, and sales commissions. If you sell nothing, your variable costs are zero.

Contribution Margin

This is the amount left over from each sale after covering the variable cost for that unit. It “contributes” to paying off fixed costs. Once fixed costs are fully covered, the contribution margin becomes pure profit.

Worked Example

A small business sells handmade candles:

• Fixed costs: $3,000/month (rent, insurance, tools)
• Variable cost per candle: $8 (wax, wick, jar, label, packaging)
• Selling price per candle: $24

The business must sell 188 candles per month to cover all costs. Candle number 189 is where profit begins. If they sell 250 candles, profit = (250 − 188) × $16 = $992.

When Break-even Is Impossible

If the variable cost per unit equals or exceeds the selling price, the contribution margin is zero or negative. Every sale either contributes nothing or actively loses money. In this situation, no amount of volume will cover fixed costs — the business model must change before it can become viable.

How to Lower Your Break-even Point

There are three levers:

1. Reduce fixed costs: Negotiate lower rent, switch to cheaper tools, or eliminate unnecessary subscriptions.
2. Reduce variable costs: Source cheaper materials, optimize production, negotiate supplier discounts.
3. Increase selling price: Add value through better branding, features, or premium positioning to justify a higher price.

Limitations of Break-even Analysis

Break-even analysis assumes that all units are sold at the same price, that variable costs per unit remain constant, and that fixed costs do not change. In reality, volume discounts, seasonal pricing, and scaling effects mean these numbers shift. Use break-even as a planning tool, not a guarantee.

Run your own numbers with the Break-even Calculator, then check your unit-level profitability with the Margin Calculator.