Break Even Calculator: Which Product Line Is Subsidizing the Others?

One product line might be subsidizing all the others. Add up to 5 lines below to find which one, and see what margin of safety the portfolio actually has once you account for each product’s contribution separately.

Break Even Calculator

Find your break even point by product line and see how sensitive your margins are.

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How to Read Your Results

Margin of safety above 15%?

Green zone. Revenue can fall by more than 15% before this line loses money. That’s enough buffer to absorb a bad quarter or a price negotiation.

Margin of safety 5-15%?

Amber zone. One price negotiation or cost increase is enough to compress this line to near break even. It needs monitoring, not panic.

Margin of safety below 5% or negative?

Red zone. A negative margin of safety means this line is already below break even and is being covered by contributions from other lines. If that surprises you, that’s the more important finding.

Key Insight: The portfolio margin of safety is not the average of individual lines. One loss-making line drags the whole number down regardless of how healthy the others are. The worst line sets the floor for business risk.

Common Mistakes

  1. Confusing fixed and variable costs. A cost is fixed if it doesn’t change with unit volume over a relevant range. When in doubt, classify a cost as fixed. Under-counting fixed costs overstates contribution margin and understates break even.
  2. Forgetting overhead allocation. Shared costs like management salaries, IT, and facilities need to be allocated across product lines. A product that looks profitable on direct costs alone can be loss-making once overhead is fairly distributed.
  3. Using list price instead of effective price. If your actual invoiced price is 12% below list due to discounts and allowances, use the effective price. List price produces a break even point that can never actually be reached by the business as it operates.

Related Tools

Gross Margin Calculator

See how each product line’s margin compares to industry benchmarks.

Working Capital Calculator

Connect profitability to cash cycle and see the full picture.

Go Deeper

  • Profitability Analysis — how to move from break even calculations to operational decisions
  • Gross Margin — how to classify COGS correctly so your contribution margin inputs are reliable
  • ABC Analysis — the same segmentation logic applied to the product portfolio