Break-Even Units Calculator
Break-even units = fixed costs ÷ (price − variable cost). With margin-of-safety vs expected volume. Founder math for SKU-based businesses. Free.
Break-Even Units Calculator
Enter your monthly (or annual) fixed costs, price per unit, and variable cost per unit. The tool returns the number of units you must sell to cover fixed costs — your break-even point. Optionally enter expected volume to see your margin-of-safety cushion.
How to Use the Break-Even Calculator
Total your fixed costs for one period
Pick monthly or annual and stick with it across all inputs. Fixed costs are anything that doesn't scale with unit volume — rent, full-time salaries, software subscriptions, insurance, accounting, fixed marketing retainers. Exclude variable costs like COGS, shipping, and payment processing.
Enter price per unit
Use net price after typical discounts and returns. If you give 10% promo discounts on 30% of orders, blended net price is 97% of list — use that, not list price.
Enter variable cost per unit
Include every cost that rises with each unit sold: the goods themselves, freight, payment-processing fees, marketplace or platform fees, packaging and an allowance for returns. Costs that stay the same whatever you sell, such as rent and salaries, belong in fixed costs.
Read margin of safety
Margin of safety is how far sales could fall before you reach break-even: expected sales minus break-even sales, shown here in units, dollars and as a share of expected sales. The higher it is, the less risk of a loss. There is no universal "safe" figure; a business with volatile sales needs more room than a steady one.
Break-Even Analysis — The First Unit Economics Question
The formula
Break-even is the volume at which revenue exactly covers costs. Each unit sold earns its contribution margin, the price minus the variable cost of that unit, and those contributions pay the fixed costs. So: break-even units = total fixed costs ÷ contribution margin per unit. The same result in dollars is fixed costs divided by the contribution margin ratio, which is the contribution margin as a share of price. This is the method set out in OpenStax, Principles of Accounting, Volume 2: Managerial Accounting, §3.2, which works the example of a tax-preparation firm with $14,000 of fixed costs and a $250 contribution per return: it breaks even at 56 returns.
This calculator rounds the unit figure up, because you cannot sell part of a unit: if the formula gives 55.2, you need 56 sales to cover your costs.
Separating fixed from variable
The result is only as good as the split between fixed and variable costs. A variable cost rises with each unit: materials, freight, card fees, marketplace commissions. A fixed cost stays the same within the period whatever you sell: rent, salaries, software, insurance. Some costs are mixed, such as utilities or a salesperson on base plus commission; split them into their two parts. Advertising is usually a fixed cost for the period, unless you genuinely pay per sale.
"The margin of safety tells the company how much they could lose in sales before the company begins to lose money."
OpenStax, §3.5Margin of safety
Margin of safety is the difference between current or expected sales and break-even sales. OpenStax puts it simply: the higher it is, the lower the risk of not breaking even. Expressed as a percentage of expected sales, it lets you compare products of different sizes. If expected sales are 1,000 units and break-even is 800, the margin of safety is 200 units, or 20%.
Three ways to move the break-even point
There are only three: raise the price, lower the variable cost per unit, or lower fixed costs. A price rise widens the contribution margin and so lowers the break-even volume, but only if customers keep buying at the new price. Try each in the calculator: change one input at a time and watch how far break-even moves. With several products, use a contribution margin weighted by the expected sales mix, and test what happens if the mix changes.
Break-even, contribution margin and margin of safety, step by step
Break-even units = total fixed costs ÷ contribution margin per unit (OpenStax, Managerial Accounting §3.2).
Contribution margin per unit = price − variable cost per unit.
The contribution margin ratio is that margin as a share of price; fixed costs ÷ the ratio gives break-even in dollars.
OpenStax's example: $14,000 of fixed costs and $250 per return break even at 56 returns.
Margin of safety = current or expected sales − break-even sales (OpenStax §3.5).
The higher the margin of safety, the lower the risk of not breaking even.
If variable cost equals or exceeds price, no volume breaks even; the calculator says so.
This calculator rounds break-even units up: you cannot sell part of a unit.
With several products, use a contribution margin weighted by sales mix.
Break-even and margin of safety are part of cost-volume-profit (CVP) analysis.
Frequently Asked Questions
- Break-even analysis finds the number of units, or the revenue, at which you cover all your costs. Break-even units are total fixed costs divided by the contribution margin per unit (price minus variable cost). Below that volume you make a loss; above it, each unit adds its contribution margin to profit.
- Variable costs rise with each unit sold: the goods themselves, freight, payment and marketplace fees, packaging. Fixed costs stay the same within the period whatever you sell: rent, salaries, software, insurance. Split mixed costs, such as base pay plus commission, into their fixed and variable parts.
- Contribution margin per unit is price minus variable cost per unit: what each sale contributes towards fixed costs and then profit. A $100 product with $35 of variable cost contributes $65. Divided by price it gives the contribution margin ratio, here 65%.
- The amount by which sales could fall before you reach break-even: expected sales minus break-even sales, in units, dollars or as a percentage of expected sales. The higher it is, the lower the risk of a loss. There is no universal safe figure; how much room you need depends on how much your sales vary.
- Usually fixed: a monthly budget for advertising, content or an agency does not change with each unit sold. Treat marketing as variable only where you really pay per sale, such as an affiliate commission. Whatever you choose, be consistent across periods.
- There is no universal target. The useful question is whether the break-even volume is realistic for your market and channels, and how much room the margin of safety leaves if sales come in lower than planned. Test the price, cost and volume assumptions one at a time and see how sensitive the answer is.
- The same way, per subscriber per month: fixed costs divided by the contribution per subscriber (subscription price minus the cost of serving one subscriber) gives the number of paying subscribers needed. A $50 subscription costing $5 a month to serve contributes $45; with $500,000 of monthly fixed costs that is about 11,112 subscribers.
- Then every sale loses money and no volume can break even, because the contribution margin is zero or negative. The calculator shows this instead of a number. Raise the price, cut the variable cost, or stop selling that product.
- Yes, with a weighted contribution margin. If product A is 70% of units with a $30 margin and product B 30% with a $50 margin, the weighted margin is 0.7 × 30 + 0.3 × 50 = $36, and break-even units are fixed costs ÷ 36. The answer changes if the mix changes, so test more than one mix.
- The formula is the same in any market; the inputs differ. Selling into the US usually adds variable costs such as international freight, import duties, marketplace fees and currency conversion, and may add fixed costs such as a local entity or compliance. Put each in the right category and in one currency, and the calculator gives the break-even for that market.
Method & sources
How it computes
Break-even units = fixed costs / (price - variable cost per unit), rounded up to a whole unit; break-even revenue = units x price; contribution margin and ratio; margin of safety = expected units - break-even units, in units, dollars and percent (OpenStax Managerial Accounting §3.2 and §3.5).
What this tool implements
- OpenStax §3.2: break-even point in units = total fixed costs / contribution margin per unit; §3.5: margin of safety = current sales - break-even sales. When variable cost exceeded price the page showed the contribution margin ratio as a fixed '0%'; it now shows the actual negative figure.
- Removed as unsourced: '30% margin of safety as the floor', CM ratios by sector, a Polaroid case, '9-18 months to bootstrap profitability', 2.9% + $0.30 card fees, Uber and Indian unicorns, and ASEAN/US salary multiples.
Sources
- OpenStax. Principles of Accounting, Volume 2: Managerial Accounting, §3.2 Calculate a Break-Even Point in Units and Dollars. Rice University. https://openstax.org/books/principles-managerial-accounting/pages…
- OpenStax. Principles of Accounting, Volume 2: Managerial Accounting, §3.5 Margin of Safety and Operating Leverage. Rice University. https://openstax.org/books/principles-managerial-accounting/pages…
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