Break-even calculator
What is a break-even calculator?
A break-even calculator estimates how many units a business must sell to cover fixed monthly costs after accounting for contribution margin per unit. It helps founders, ecommerce brands, SaaS teams, agencies, CPG operators, retailers, and service businesses understand whether pricing, variable cost, and sales volume can support rent, payroll, software, marketing, and other overhead.
Break-even formula
The break-even formula divides fixed costs by contribution margin per unit. Contribution margin is the difference between the selling price and the variable cost required to deliver one unit.
Break-even units = Fixed monthly costs / (Selling price per unit - Variable cost per unit)- Contribution margin per unit = Selling price per unit - Variable cost per unit.
- The formula only works when contribution margin is positive.
- For cash planning, layer inventory purchases, loan payments, tax timing, and accounts receivable on top of accounting break-even.
Inputs explained
Break-even analysis is most useful when fixed and variable costs are classified consistently with how finance measures unit economics.
- Fixed monthly costs ($)
- The overhead that stays relatively constant regardless of how many units are sold during the month. Examples include rent, salaries, software, insurance, equipment leases, baseline marketing retainers, and administrative expenses.
- Selling price per unit ($)
- The average realized price collected per unit after routine discounts, promotions, channel fees, or rebates if those are part of normal selling economics. Use net realized price rather than list price when discounting is common.
- Variable cost per unit ($)
- The incremental cost required to produce, fulfill, deliver, or support one additional unit. This can include materials, packaging, payment fees, shipping, commissions, usage-based COGS, contractor labor, or transaction costs.
- Units to sell per month
- The estimated monthly unit volume needed to cover fixed costs before generating operating profit. It is a planning threshold, not a cash-flow guarantee.
Example break-even calculation
If a business has $15,000 in fixed monthly costs, sells each unit for $99, and spends $22 in variable cost per unit, contribution margin is $77 per unit. The business needs to sell about 195 units per month to break even before debt service, taxes, owner draws, inventory timing, or working-capital needs.
Break-even calculator
Monthly units needed to cover fixed costs
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How to estimate monthly break-even unit volume
- Roll rent, salaried overhead, mandatory software, and baseline marketing your FP&A classifies as fixed into “Fixed monthly costs”—exclude purely variable commissions unless already folded into contribution.
- Enter realized average selling price net of routine discounts into “Selling price per unit,” then burden direct materials, fulfillment, usage-based COGS, and variable merchant fees under “Variable cost per unit.”
- Subtract variable from price mentally to confirm contribution margin stays positive before trusting “Units to sell per month.”
- Stress-test by raising variable logistics five points when fuel surcharges spike—break-even climbs nonlinearly when throughput assumptions ignore seasonality.
Common break-even analysis mistakes
- Using list price instead of realized selling price after discounts and channel fees.
- Leaving commissions, payment fees, packaging, freight, or usage-based costs out of variable cost.
- Putting variable costs into fixed overhead or fixed salaries into unit cost without a clear policy.
- Assuming break-even units equal cash break-even when inventory, debt, taxes, and receivables affect cash timing.
- Using one average unit for a multi-product business with very different margins.
- Ignoring capacity limits, seasonality, stockouts, or sales constraints that make the break-even volume unrealistic.
- Treating break-even as a profit target instead of the minimum volume needed to cover fixed costs.
Break-even planning anchors
- Contribution-margin sanity checks taught in FP&A boot camps
- Selling price minus incremental variable cost must stay positive—otherwise the denominator collapses toward zero and break-even volume blows up
- Typical distinction between accounting break-even and cash break-even
- Non-cash depreciation and working-capital swings often delay true cash neutrality—layer thirteen-week cash models beyond unit math
- Retail / CPG guardrail when promotions compress realized price
- Use net realized selling price after discounts and slotting unless promo spend is explicitly modeled as variable elsewhere
Best use cases
- Growth and performance planning
- Budget and forecast scenario modeling
- Client-facing pre-qualification and education
FAQs
Should commissions paid only on closed revenue sit in variable cost per unit?
Usually yes—incremental payout scales with units sold. If commissions are flat draws guaranteed regardless of volume, finance often keeps them fixed—misclassification swings break-even materially.
Why does my cash runway disagree with this break-even output?
Accrual fixed costs exclude timing realities—loan principal, inventory builds, and AR lag burn cash even when accounting contribution hits zero profit.
Can unit price equal variable cost in this model?
No useful break-even exists—denominator hits zero and contribution vanishes. Raise price, cut variable waste, or rebundle SKUs before chasing volume.
How do multi-product portfolios map into one unit?
Either blend SKUs into weighted-average price and variable costs or run separate calculators per line—single-unit abstraction hides mix shift risk.
How do I calculate break-even if I sell multiple products with different margins?
Use a weighted-average contribution margin based on expected sales mix, or calculate break-even separately by product line. If the mix shifts toward lower-margin products, the business may need more units than the blended model suggests.
Should owner salary be included in fixed monthly costs?
Include owner salary if the business needs to pay that amount to be economically sustainable. If you exclude owner compensation, the calculator may show accounting break-even while the owner is effectively subsidizing the business with unpaid labor.
How do discounts and promotions affect break-even volume?
Discounts reduce realized selling price and therefore reduce contribution margin per unit. Even a small discount can increase break-even volume sharply when margins are already thin. Model promoted price separately before running a campaign.
How can I use break-even analysis before raising prices?
Run the current price and proposed price as separate scenarios. A higher price usually lowers required unit volume, but only if demand does not fall enough to offset the margin gain. Compare break-even volume with realistic sales volume at each price.
Why can my business hit break-even units but still lose money?
The model covers fixed costs and variable costs in a simplified operating view. Losses can still appear from debt payments, taxes, inventory write-offs, returns, uncollected invoices, owner draws, depreciation treatment, or costs that were left out of the model.
How do I know if my break-even target is realistic?
Compare required units with historical sales volume, conversion rate, production capacity, staffing, inventory availability, and market demand. If the break-even volume is far above what the business can realistically sell, the fix is usually pricing, cost reduction, product mix, or overhead reduction.
Glossary
Scenario modeling
Comparing multiple assumption sets to estimate potential outcomes before execution.
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User behavior that indicates readiness to take a commercial action such as signup or purchase.
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Category: Managerial accounting & unit economicsTopics: Break-even volume, Contribution margin, Fixed cost coverage
Last reviewed: 2026-05-07
Reviewed by: Calclet Growth Team