Senior engineering leaders are expected to understand the business. There is a lot of sales, marketing, customer success, and financial jargon that arrives with that responsibility. This is a short glossary of common terms and why they matter.

ARR - Annual Recurring Revenue

Why: ARR tells you how much revenue the company brings in on an annual basis from subscriptions.

How: total subscription income per year, plus recurring revenue from add-ons or upgrades, minus revenue lost from cancellations.

Target: bigger is better.

CAC - Customer Acquisition Cost

Why: CAC shows how much the company spends to sign a new customer.

How: add up sales and marketing spend in a period and divide by the number of customers acquired in that period.

Target: smaller is better.

LTV - Lifetime Value

Why: LTV estimates how much revenue you can expect from a customer while they remain a customer.

How: calculate average purchase price and multiply by the number of times they purchase or renew.

Target: bigger is better.

LTV/CAC Ratio

Why: this compares the lifetime value of a customer to the cost of bringing them onboard. It tells you whether the acquisition strategy is sustainable.

How: LTV divided by CAC.

Target: below 1.0 destroys value. Above 1.0 may create value. A common rule of thumb is that above 3.0 is good.

Net Monthly Recurring Revenue Growth

Why: this measures the month-over-month change in net MRR as new revenue is added, customers churn, and accounts expand or contract.

How: net MRR this month minus net MRR last month, divided by net MRR last month.

ARPA - Average Revenue Per Account

Why: ARPA shows how much each account generates and can help model future income.

How: ARR divided by number of accounts, or MRR divided by number of accounts for a monthly view.

Target: bigger is better.

EBITDA - Earnings Before Interest, Taxes, Depreciation, and Amortization

Why: EBITDA focuses on operating profitability and cash flow. It is often used as a proxy for operating cash flow.

How: net income plus taxes, interest expense, depreciation, and amortization.

Target: a higher EBITDA margin generally means stronger operating profitability.