| Revenue | Total sales before expenses | Top-line money earned | Growth rate >20% YoY (varies by stage) | Revenue growing slower than costs |
| ARPU | Total Revenue / Total Users | Revenue per individual user | Varies by model; track trend | ARPU declining cohort-over-cohort |
| ARPA | MRR / Active Accounts | Revenue per customer account | SMB: $100-$1K; Mid: $1K-$10K; Ent: $10K+ | High ARPA + low ARPU (undermonetized seats) |
| ACV | Annual Recurring Revenue per Contract | Annualized contract value | SMB: $5K-$25K; Mid: $25K-$100K; Ent: $100K+ | ACV declining (moving downmarket unintentionally) |
| MRR/ARR | MRR × 12 = ARR | Predictable recurring revenue | Growth + quality matter; track components | New MRR declining while churn stable/growing |
| Churn Rate | Customers Lost / Starting Customers | % of customers who cancel | Monthly <2% great, <5% ok; Annual <10% great | Churn increasing cohort-over-cohort |
| NRR | (Start ARR + Expansion - Churn - Contraction) / Start ARR × 100 | Revenue retention + expansion | >120% excellent; 100-120% good; 90-100% ok | NRR <100% (base is contracting) |
| Expansion Revenue | Upsells + Cross-sells + Usage Growth | Additional revenue from existing customers | 20-30% of total revenue | Expansion <10% of MRR |
| Quick Ratio | (New MRR + Expansion MRR) / (Churned MRR + Contraction) | Revenue gains vs. losses | >4 excellent; 2-4 healthy; <2 leaky bucket | Quick Ratio <2 (leaky bucket) |
| Gross Margin | (Revenue - COGS) / Revenue × 100 | % of revenue after direct costs | SaaS: 70-85% good; <60% concerning | Gross margin <60% or declining |
| CAC | Total S&M Spend / New Customers | Cost to acquire one customer | Varies: Ent $10K+ ok; SMB <$500 | CAC increasing while LTV flat |
| LTV | ARPU × Gross Margin % / Churn Rate | Total revenue from one customer | Must be 3x+ CAC; varies by segment | LTV declining cohort-over-cohort |
| LTV:CAC | LTV / CAC | Unit economics efficiency | 3:1 healthy; <1:1 unsustainable; >5:1 underinvesting | LTV:CAC <1.5:1 |
| Payback Period | CAC / (Monthly ARPU × Gross Margin %) | Months to recover CAC | <12 months great; 12-18 ok; >24 concerning | Payback >24 months (cash trap) |
| Contribution Margin | (Revenue - All Variable Costs) / Revenue × 100 | True contribution after variable costs | 60-80% good for SaaS; <40% concerning | Contribution margin <40% |
| Burn Rate | Monthly Cash Spent - Revenue | Cash consumed per month | Net burn <$200K manageable early; <$500K growth | Net burn accelerating |
| Runway | Cash Balance / Monthly Net Burn | Months until money runs out | 12+ months good; 6-12 ok; <6 crisis | Runway <6 months |
| OpEx | S&M + R&D + G&A | Costs to run the business | Should grow slower than revenue | OpEx growing faster than revenue |
| Net Income | Revenue - All Expenses | Actual profit/loss | Early negative ok; mature 10-20%+ margin | Losses accelerating without growth |
| Rule of 40 | Revenue Growth % + Profit Margin % | Balance of growth vs. efficiency | >40 healthy; 25-40 ok; <25 concerning | Rule of 40 <25 |
| Magic Number | (Q Revenue - Prev Q Revenue) × 4 / Prev Q S&M | S&M efficiency | >0.75 efficient; 0.5-0.75 ok; <0.5 fix GTM | Magic Number <0.5 |
| Operating Leverage | Revenue Growth vs. OpEx Growth | Scaling efficiency | Revenue growth > OpEx growth | OpEx growing faster than revenue |
| Gross vs. Net Revenue | Net = Gross - Discounts - Refunds - Credits | What you actually keep | Refunds <10%; discounts <20% | Refunds >10% (product problem) |
| Revenue Concentration | Top N Customers / Total Revenue | Dependency on largest customers | Top customer <10%; Top 10 <40% | Top customer >25% (existential risk) |
| Revenue Mix | Product/Segment Revenue / Total Revenue | Portfolio composition | No single product >60% ideal | Single product >80% (no diversification) |
| Cohort Analysis | Group customers by join date; track behavior | Whether business improving or degrading | Recent cohorts same/better than old | Newer cohorts perform worse |
| CAC Payback by Channel | CAC / Monthly Contribution (by channel) | Payback by acquisition channel | Compare across channels | One channel far worse than others |
| Gross Margin Payback | CAC / (Monthly ARPU × Gross Margin %) | Payback using actual profit | Typically 1.5-2x simple payback | Payback using margin >36 months |
| Unit Economics | Revenue per unit - Cost per unit | Profitability of each "unit" | Positive contribution required | Negative contribution margin |
| Segment Payback | CAC / Monthly Contribution (by segment) | Payback by customer segment | Compare to allocate resources | One segment unprofitable |
| Incrementality | Revenue caused by action - Baseline | True impact of marketing/promo | Measure with holdout tests | Celebrating revenue that would've happened anyway |
| Working Capital | Cash timing between revenue and collection | Cash vs. revenue timing | Annual upfront > monthly billing | Long payment terms killing runway |