Break even calculator: how to calculate your break-even point

TL;DR:

• Break-even point (units) = fixed costs ÷ (price per unit minus variable cost per unit).
• Break-even point (revenue) = fixed costs ÷ contribution margin ratio.
• Contribution margin is what’s left from each sale after variable costs, before fixed costs are covered.
• Price, fixed costs and variable costs each move your break-even point differently, so it’s worth testing scenarios rather than calculating once.
• A break even calculator built into your plan updates automatically when your numbers change; a spreadsheet formula does not.

A break even calculator answers one question: how much do you need to sell before you stop losing money and start making it? The formula is fixed costs divided by price per unit minus variable cost per unit. Get that number right and you have a concrete sales target, not a guess. This post is the practical side of the maths. If you want the concept explained first, our guide to what break-even analysis is covers that ground and won’t be repeated here.

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The break-even formula, stated plainly

Break-even point in units = Fixed costs ÷ (Price per unit − Variable cost per unit)

Fixed costs are the ones that don’t move with sales volume: rent, insurance, salaries you pay regardless of how much you sell. Variable costs move with each unit sold or each customer served: materials, packaging, transaction fees, sales commission. The gap between price and variable cost per unit is your contribution margin.

What is contribution margin?

Contribution margin is the amount left over from each sale once variable costs are deducted. It’s the amount each sale “contributes” towards covering your fixed costs, and once fixed costs are covered, towards profit. Contribution margin per unit = price per unit minus variable cost per unit.

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Break-even in units versus break-even in revenue

These are two different questions with two different formulas. Mixing them up is one of the most common errors people make with a break even calculator.

Break-even in units

Use this when you sell distinct items and want to know how many you need to shift.

Break-even point (units) = Fixed costs ÷ (Price per unit − Variable cost per unit)

Break-even in revenue

Use this when you sell a range of products or services at different prices, or when a single “unit” doesn’t make sense, such as a subscription or consultancy day rate.

Break-even point (revenue) = Fixed costs ÷ Contribution margin ratio

Contribution margin ratio = Contribution margin per unit ÷ Price per unit. This gives you a percentage, which you then divide into your fixed costs to get a revenue target rather than a unit count.

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Worked example: a product business

Take a small business selling handmade candles.

• Selling price per candle: £18
• Variable cost per candle (wax, wick, jar, packaging): £7
• Fixed costs per month (studio rent, insurance, part-time wage): £2,200

Contribution margin per candle = £18 − £7 = £11

Break-even point (units) = £2,200 ÷ £11 = 200 candles per month

So this business needs to sell 200 candles a month before it covers its costs. Candle 201 onwards is where profit starts.

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Worked example: a service or subscription business

Take a small software subscription business charging a monthly fee.

• Average monthly subscription price: £40
• Variable cost per customer (hosting, payment processing, support time): £6
• Fixed costs per month (salaries, software licences, office): £9,000

Contribution margin per customer = £40 − £6 = £34

Contribution margin ratio = £34 ÷ £40 = 0.85, or 85%

Break-even point (revenue) = £9,000 ÷ 0.85 = £10,588 per month

Break-even point (customers) = £9,000 ÷ £34 = roughly 265 subscribers

Subscription businesses often find revenue-based break-even more useful because pricing tiers vary. If you’re building this kind of model, our piece on cash flow forecasting for SaaS businesses goes further into recurring revenue mechanics.

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What moves your break-even point?

Break-even isn’t a fixed number. It shifts every time one of the three inputs changes, and it’s worth knowing which way each one pushes it.

If price per unit rises

Contribution margin per unit increases, so you need fewer sales to break even. Even a small price increase can lower your break-even point noticeably, because the effect compounds across every unit sold.

If fixed costs rise

Break-even point rises directly. Taking on more rent, more salaried staff or a new software subscription raises the bar before every one of those costs turns into your own profit.

If variable cost per unit rises

Contribution margin per unit shrinks, so break-even point rises. This is the one people underestimate, because a small increase in materials or supplier costs on every unit adds up fast across volume. If your costs are exposed to inflation, our guide on managing inflation in Brixx is directly relevant here.

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Common mistakes when calculating break-even

Mixing up fixed and variable costs

A cost that’s fixed in one business can be variable in another. Sales commission is variable; a fixed salary is not. Get this categorisation wrong and every downstream number is wrong too.

Forgetting tax treatment

Break-even calculations are usually done pre-tax, but if you’re using the result to plan how much cash you actually keep, you need to layer tax on separately. Don’t quietly assume post-tax and pre-tax numbers are interchangeable.

Inconsistent owner salary

If you don’t pay yourself a fixed amount consistently, it’s tempting to leave your own salary out of fixed costs. That understates your true break-even point. Decide on a figure, even a modest one, and include it.

Using revenue instead of contribution

Dividing fixed costs by total revenue, rather than by contribution margin, is a common shortcut that gives a misleadingly low break-even figure. Contribution margin, not revenue, is what actually pays down fixed costs.

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Why a spreadsheet break-even formula goes stale

A manual break even calculator is useful for a single snapshot. The problem is that prices change, suppliers put costs up, and fixed costs shift as you hire or move premises. Each change means updating the spreadsheet formula by hand, and it’s easy to forget.

Brixx includes a Breakeven Chart that’s generated directly from your financial plan rather than a formula you maintain separately. Because Brixx models your business through Components (the individual costs, revenue streams and assets that make up your plan), whether something is fixed or variable falls out of how you’ve set that component up. Change a price or a supplier cost anywhere in your plan and the break-even chart updates with it, alongside your cash flow forecast, profit and loss and balance sheet.

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Getting started without historical figures

If you’re pre-launch and don’t have real sales or cost data yet, you can still build a credible break-even estimate using researched assumptions for pricing and supplier costs. Our guide on creating a financial forecast with no historical data walks through how to build reasonable assumptions from scratch, and a pre-built industry template from our templates and downloads library can give you a sensible starting structure for fixed and variable costs.

Once you have a working break-even figure, revisit it whenever a major input changes, and consider testing a few scenarios rather than relying on one. Our post on improving your business’ financial forecasting covers why single-point estimates tend to age badly.

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Frequently asked questions

Break-even point

The break-even point is the level of sales at which total revenue equals total costs, meaning the business makes neither a profit nor a loss.

What is the simplest break-even formula?

Break-even point (units) = fixed costs ÷ (price per unit minus variable cost per unit). This tells you how many units you need to sell to cover your costs.

How do I calculate break-even in revenue rather than units?

Divide fixed costs by your contribution margin ratio (contribution margin per unit divided by price per unit). This is useful when you sell multiple products or services at different prices.

Does break-even analysis account for tax?

Not by default. Standard break-even calculations are pre-tax. If you need a post-tax picture, add tax as a separate step after finding your break-even figure.

Why does my break-even point keep changing?

Because price, fixed costs and variable costs all move independently. A change to any one of them shifts the number, which is why a maintained plan is more reliable than a one-off spreadsheet calculation.