Walk into any room of founders and ask each one to recite their monthly revenue. Most will get close. Ask the same room what their gross margin is, what their cash runway is, and what it cost them to acquire their last customer, and the room goes quiet. Revenue is the comfortable number because it sounds biggest, but it is not the one that decides whether a business lives through the next 12 months. The 5 numbers below are not optional for any founder running past the side hustle stage. You should be able to recite each one in under 10 seconds and explain the trend in under 30.
The first number is cash runway in months. Take your bank balance, divide by your average monthly burn, and you have it. A founder with $48,000 in the bank and $12,000 in monthly burn has 4 months of runway, which is a fire alarm. Anything under 6 months should be the only thing you are thinking about until you fix it. Anything between 6 and 12 should be the lens for every spending decision you make that quarter. The reason most founders cannot recite this number is that they confuse cash with revenue and assume strong months will keep coming, which is the assumption that has ended more small businesses than any product mistake.
The second number is gross margin. This is revenue minus the direct cost of delivering the product or service, divided by revenue. A coaching business doing $20,000 a month with $2,000 in delivery costs has a 90 percent gross margin. A reseller doing the same $20,000 with $14,000 in cost has a 30 percent margin, and the two businesses are not even close to comparable. Knowing this number tells you how much of every new dollar actually funds your overhead, your salary, and your growth. Founders who optimize for top line and ignore this number end up working harder every year while the bank balance stays flat. Healthy targets vary by industry, but anything under 40 percent for a service business or under 25 percent for product should trigger a serious pricing or sourcing conversation.
The third number is monthly cash collections, not monthly invoiced revenue. There is a real difference between the two, and that difference is where many small businesses get into trouble. You can invoice $30,000 in May and only collect $14,000 by month end because half your clients are slow payers and one is in dispute. Cash is what pays rent, payroll, and contractors, not invoices. Track collections weekly, not monthly, and you will notice payment problems three weeks earlier than your bookkeeper would tell you. Founders who confuse the invoice with the deposit are usually the ones surprised when payroll runs short, even though revenue on paper looked healthy.
The fourth number is customer acquisition cost. Add up everything you spent on marketing and sales in a month, divide by the number of new paying customers you got, and you have it. If you spent $2,400 on ads and onboarding and brought in 6 new clients at $200 each, your CAC is $400 against an average first month revenue of $200, which is a money losing setup unless those clients stay long enough to recoup. The number tells you whether your channel mix is sustainable or whether you are buying revenue at a loss. Most founders track ad spend without ever computing this ratio, which is how Facebook and Google end up taking the margin that was supposed to fund the business. Run the math every month and kill any channel where CAC exceeds the first 6 months of revenue from that customer.
The fifth number is customer lifetime value, often expressed against CAC as the LTV to CAC ratio. Lifetime value is average monthly revenue per customer multiplied by average months retained, minus the cost to serve them. A subscription earning $80 a month with 14 month retention and $10 delivery cost has an LTV of $980. If your CAC is $200, your LTV to CAC ratio is just under 5 to 1, which is healthy. Anything under 3 to 1 means you are spending too much to bring people in, and anything over 5 to 1 sometimes means you are underspending on growth. Track this quarterly because retention moves slowly, and use it to make every paid acquisition decision next quarter.
Put all 5 numbers on the front page of a spreadsheet and update them on the first Monday of every month. A founder who can recite cash runway, gross margin, monthly cash collections, CAC, and LTV in 10 seconds can make pricing, hiring, and marketing decisions with real confidence. A founder who cannot is gambling, even when revenue looks fine on the surface. The math is not difficult. The discipline is. Pick a Monday in the next two weeks, calculate all 5, and update them every month for the rest of the year.
