पाठशाला Pathshala · हिसाब Hisāb, Unit economics · Lesson 21 · Build
Break-even and operating leverage
Break-even is fixed cost divided by contribution margin, and it moves every time you hire. Operating leverage is why profit swings harder than revenue near that line, in both directions.
Pathshala, The Founder Library · 11 October 2026 · 7 min read
There is one revenue figure at which a company stops losing money. Most founders know it only roughly, and almost none know how it moved the last time they hired. Yet it is a single division, and the shape of the line through it explains why profit behaves so differently from revenue.
This lesson computes break-even, explains operating leverage as the slope of profit against revenue, shows why turning fixed cost into variable cost is not the free safety it looks like, deals with costs that rise in steps, and ends with a monthly line every founder can draw.
Break-even is one division
Split every cost into two kinds. Variable costs move with revenue: cost of goods, payment fees, courier, cloud usage that scales with customers, sales commissions. What is left of each rupee of revenue after them is the [contribution margin](/library/contribution-margin-first-number-to-know). Fixed costs do not move in the month whatever is sold: salaries of the core team, rent, annual software, the auditor. Break-even revenue is monthly fixed cost divided by contribution margin.
A Gurugram company selling compliance software to factories has ₹50 lakh a month of fixed cost, mostly salaries, and keeps 70 per cent of each rupee of revenue after hosting, payment fees and the onboarding staff it pays per customer. Break-even is ₹50 lakh divided by 0.7, or ₹71.4 lakh of revenue a month. It is billing ₹60 lakh, so it loses ₹8 lakh a month. The gap to break-even is ₹11.4 lakh of monthly revenue, which at its average contract of ₹40,000 a month is twenty-nine more customers, or a price rise, or a smaller fixed-cost line, or some mix of the three by a date.
Compute break-even on contribution margin, not on gross margin, whenever the two differ. Gross margin leaves out commissions, payment fees and the other costs of selling each unit, and a break-even computed on it is too low. The test for any cost is the same one the contribution lesson uses: if the company sold nothing next month, would this cost disappear?
Fixed costs set the slope
Draw profit against revenue and you get a straight line. It crosses zero at break-even. Its slope is the contribution margin: each extra rupee of revenue adds seventy paise of profit in Gurugram. Its starting point, at zero revenue, is minus the fixed cost. Operating leverage is the name for what that shape does. The higher the share of a company’s cost that is fixed, the higher its contribution margin tends to be and the steeper the line, so profit rises fast above break-even and falls fast below it.
Near break-even the effect is extreme. If the Gurugram company reaches ₹80 lakh of revenue, contribution is ₹56 lakh and profit is ₹6 lakh. A further 10 per cent of revenue adds ₹5.6 lakh of profit, a 93 per cent rise. The ratio of contribution to profit, here about 9.3, is the degree of operating leverage: the percentage change in profit for each one per cent change in revenue. It falls as the company moves away from break-even, and it works in reverse. A 10 per cent fall from ₹80 lakh wipes out nearly all the profit. This is why a company just past break-even can report a profitable quarter and a loss-making one on revenue that barely moved.
Bill Gurley listed marginal profitability among the qualities that make revenue valuable in All Revenue is Not Created Equal: if the profit on the next rupee of revenue is much higher than the company’s historical profitability, he wrote, the company is scaling nicely. Investors read the slope, not just the point.
Two companies with the same loss
Founders who are nervous about fixed cost often try to make it variable: contractors paid per job instead of salaried staff, a revenue share to a partner instead of a sales team, usage-priced tools instead of annual licences. The instinct is sound. Variable cost falls when revenue falls, so the company loses less in a bad month. But it has a price, and the figure shows it.
The figure opens on Gurugram. The grey line moves 30 per cent of the fixed cost, ₹15 lakh, into variable cost at this month’s revenue, so the company loses the same ₹8 lakh this month either way. But its contribution margin drops from 70 to 45 per cent, and break-even moves out from ₹71.4 lakh to ₹77.8 lakh. A company below break-even that is planning to grow through it has made its target harder in exchange for a softer fall if revenue drops. Drag the revenue slider above break-even and the trade becomes plainer still: the green line pulls away and the grey one follows slowly.
Neither structure is right in general. A company with uncertain demand and little cash is right to keep cost variable until demand is proven. A company with demand it can see and a plan to grow past break-even should accept fixed cost, because the slope is where the profit will come from. The mistake is choosing one without seeing the other.
When fixed cost is not fixed
Fixed cost is fixed only within a range. A support team of four can handle a certain number of customers; the fifth hire arrives when the queue breaks. A warehouse fills; the next one costs the same whether it is half full or not. Each of these is a step, and each step moves break-even up at once by the step divided by contribution margin. A ₹6 lakh monthly hire in Gurugram adds ₹8.6 lakh to break-even revenue the day the offer letter is signed.
So plan the steps rather than discovering them. List the next three hires or commitments, the month each is expected and the revenue level that triggers it. Compute break-even after each one. If a step lands before the revenue that justifies it, the company has hired ahead of demand, which can be right, but should be a decision with a number attached and not a drift.
Steps work downwards too, and that is the lever founders forget when revenue stalls. Ending an office lease, moving a tool from an annual plan to a monthly one, or not replacing a departing manager each lowers break-even by the saving divided by contribution margin. In Gurugram, ₹4 lakh a month of savings brings break-even down by ₹5.7 lakh of revenue, which is half the gap the company currently has to close. A founder who knows the size of each step can tell the board, in one sentence, how much of the distance to break-even can be covered by cost and how much has to come from sales.
Break-even is not a number you reach once. It is a line that moves every time fixed cost does, and it has to be redrawn each time.
Operating leverage in published numbers
Listed companies show the gap between contribution and profit plainly. Swiggy’s Q4 FY25 shareholder letter reported its food delivery contribution margin at 7.8 per cent of gross order value and adjusted EBITDA at 2.9 per cent. The difference, about five points, is the cost of running the business that does not move with each order. As order value grows faster than that cost, adjusted EBITDA margin climbs toward contribution margin. That is operating leverage at work in a low-margin business, and it is why the letter reports both lines every quarter.
Break-even with a date
Paul Graham’s question in Default Alive or Default Dead? is break-even with a date attached: with expenses held constant and revenue growing at its recent rate, does the company reach profitability on the money it has left? Put the Gurugram company’s break-even next to its revenue growth. At ₹60 lakh growing 4 per cent a month, ₹71.4 lakh arrives in about five months; at 2 per cent, in about nine. If the bank holds ₹3 crore, losses on the way are small either way and it is default alive. If it holds ₹25 lakh, the second path ends before break-even and the company needs to cut fixed cost, raise price or raise money now, not in month eight.
The monthly break-even line
On the day the monthly MIS is closed, compute four numbers and write them on one line: fixed cost for the month, contribution margin for the month, break-even revenue, and actual revenue as a percentage of break-even. Plot the last percentage for each of the last twelve months. Above a hundred, also compute the degree of operating leverage, so the board knows how sensitive the next quarter’s profit is to revenue.
Then look forward. List the fixed-cost steps planned for the next two quarters and the break-even after each. Put the month you expect revenue to cross the latest break-even next to the month the runway ends. If the second comes first, the plan does not work, and this is the meeting at which to say so.
Nothing here is legal, tax or investment advice. The Gurugram company is illustrative; your own contribution margin and fixed-cost line are the only inputs that matter.
Sources
- Bill Gurley, All Revenue is Not Created Equal: The Keys to the 10X Revenue Club, Above the Crowd, May 2011 — Marginal profitability higher than historical profitability as a sign a company is scaling.
- Swiggy Limited, Q4 FY2025 Shareholder Letter, May 2025 — Food delivery contribution margin 7.8 per cent and adjusted EBITDA 2.9 per cent of GOV.
- Paul Graham, Default Alive or Default Dead?, October 2015 — Profitability on the money left, at constant expenses and recent revenue growth.