Unit Economics, LTV and CAC Payback: Building Efficient Growth

Analyzing and Improving Unit Economics

Building sustainable growth through unit economics discipline. **Unit economics fundamentals** Definition: - Profit per customer over their lifetime - Key to understanding if business is scalable - If unit economics bad, growth burns cash fast - If unit economics good, growth compounds Three key metrics: 1. CAC (Customer Acquisition Cost) - What does it cost to acquire 1 customer? - Includes: Sales, marketing, commissions, tools - Formula: Marketing spend / Customers acquired 2. LTV (Lifetime Value) - Total profit from customer over lifetime - Includes: Revenue from customer, minus service costs - Formula: Profit per month × Customer lifetime (months) 3. Payback period - How long to recover acquisition cost from customer profit? - Formula: CAC / Monthly profit - Key metric: If <12 months, sustainable Relationship: - LTV must be > CAC (earn back acquisition cost) - Ideally LTV > 3 × CAC (earn back 3x) - If LTV < CAC, you're losing money on each customer **CAC calculation and analysis** CAC formula: CAC = Total marketing spend / New customers acquired Components of marketing spend: Sales and marketing salaries: - Sales team: 2 people × £50K salary = £100K/year - Marketing team: 1 person × £40K = £40K/year - Total: £140K/year Advertising spend: - Google Ads: £5K/month = £60K/year - Facebook Ads: £2K/month = £24K/year - LinkedIn Ads: £1K/month = £12K/year - Total: £96K/year Tools and software: - CRM (Salesforce): £2K/month = £24K/year - Marketing automation: £1K/month = £12K/year - Analytics: £500/month = £6K/year - Total: £42K/year Total annual spend: £140K + £96K + £42K = £278K New customers acquired (annually): 200 customers CAC = £278K / 200 = £1,390 per customer CAC by channel: | Channel | Spend | Customers | CAC | |---|---|---|---| | Google Ads | £60K | 80 | £750 | | Facebook Ads | £24K | 40 | £600 | | LinkedIn Ads | £12K | 20 | £600 | | Sales team | £100K | 50 | £2000 | | Organic/inbound | £0 | 10 | £0 | | **Total** | **£278K** | **200** | **£1390** | Insights: - Organic: £0 CAC (free, but small volume) - Paid ads: £600-750 CAC (efficient) - Sales: £2000 CAC (expensive, but high-value deals?) - Blended: £1390 (reasonable, but varies by channel) Optimization opportunities: - Increase organic (save CAC) - Shift from sales to ads (lower CAC) - Improve ad targeting (lower CAC, same volume) **LTV calculation and analysis** LTV formula: LTV = (ARPU × Gross margin × Customer lifetime) - Acquisition cost Components: ARPU (Average Revenue Per User): - Current: £100/month - Growing: 2-3% annually - Calculate: Total revenue / Number of customers Gross margin: - Revenue: £100 - COGS (hosting, support, payment processing): £30 - Gross profit: £70 - Gross margin: 70% Customer lifetime: - Monthly churn: 5% - Expected lifetime: 1 / 0.05 = 20 months - Alternative: Retention rate 95%, year 1-3 retention improves to 98% - Assume: 25 months average (blended) Acquisition cost: - Calculated above: £1,390 LTV calculation: LTV = (£100 × 70% × 25 months) - £1,390 LTV = (£70/month × 25 months) - £1,390 LTV = £1,750 - £1,390 LTV = £360 Wait, that's low! Let's recalculate with more realistic numbers: Alternative (higher LTV): ARPU: £150 (higher-tier customers) Gross margin: 75% (improved ops) Lifetime: 30 months (lower churn) CAC: £1,200 (more efficient) LTV = (£150 × 75% × 30) - £1,200 LTV = (£112.50/month × 30 months) - £1,200 LTV = £3,375 - £1,200 LTV = £2,175 Much healthier! LTV £2,175 vs CAC £1,200 = ratio 1.8:1 (decent, target 3:1) **Payback period** Definition: - How long until customer profit covers acquisition cost? - After payback, customer is profitable - Before payback, you're burning cash Formula: Payback period = CAC / Monthly gross profit Example: CAC: £1,200 Monthly gross profit: £150 × 75% = £112.50 Payback: £1,200 / £112.50 = 10.7 months Interpretation: - Payback in 10.7 months - After month 11, customer is profitable - Lifetime: 30 months, payback month 11 - Profitable months: 30 - 11 = 19 months profit = £2,137.50 profit (rough) - Plus profit from referrals (promoters refer) Benchmark payback by stage: | Stage | Payback | Status | Action | |---|---|---|---| | Seed | <6 months | Excellent | Scale acquisition | | Series A | 6-12 months | Good | Sustainable | | Series B | 12-18 months | Acceptable | Monitor closely | | Mature | 18-24 months | Concerning | Optimize urgently | | >24 months | Crisis | Must improve | Change model | **LTV:CAC ratio and decision-making** Ratio benchmark: | Ratio | Status | Action | |---|---|---| | >5:1 | Excellent | Can spend 20% of LTV on CAC | | 3-5:1 | Healthy | Sustainable growth | | 1.5-3:1 | Acceptable | Must improve to scale | | 1-1.5:1 | Poor | Unprofitable, must fix | | <1:1 | Disaster | Losing money on each customer | Example analysis: Company A: - LTV: £2,000 - CAC: £500 - Ratio: 4:1 (healthy) - Can spend more on CAC (up to £600-700 while staying healthy) Company B: - LTV: £1,500 - CAC: £1,200 - Ratio: 1.25:1 (poor) - Must improve LTV or reduce CAC - Actions: Increase ARPU, reduce churn, improve retention **Improving unit economics** Lever 1: Increase ARPU Tactics: - Upsell (upgrade customers to higher tier): +20-30% ARPU - Cross-sell (sell additional products): +10-20% ARPU - Price increase (raise prices annually): +3-5% ARPU - Product-led growth (self-serve, higher tier): +10-15% ARPU Example impact: - Current ARPU: £100 - Upsell: Increase 30% → £130 ARPU - LTV impact: (£130 × 70% × 25) - £1,200 = £2,275 - £1,200 = £1,075 (+£280) - Ratio improvement: 1.8:1 → 2.3:1 Lever 2: Improve retention (reduce churn) Tactics: - Better onboarding: -1% churn (20 month lifetime → 25 month) - Customer success: -1% churn - Product improvements: -2% churn Example impact: - Current churn: 5% (20-month lifetime) - Improve to 3% (33-month lifetime) - LTV: (£100 × 70% × 33) - £1,200 = £2,310 - £1,200 = £1,110 (+£750) - Huge impact! (churn is high-leverage) Lever 3: Reduce CAC Tactics: - Improve ad targeting: -20% CAC - Increase organic: Shift budget - Improve sales efficiency: -15% CAC - Channel optimization: Focus on efficient channels Example impact: - Current CAC: £1,200 - Improve to £1,000 (-17%) - LTV: (£100 × 70% × 25) - £1,000 = £750 - £1,000 = -£250 (still negative) - CAC reduction alone not enough, combine with other levers Lever 4: Improve gross margin Tactics: - Reduce hosting costs: -2% COGS - Reduce support costs: -1% COGS - Improve pricing: +5% ARPU Example impact: - Current: 70% margin - Improve to 75% - LTV: (£100 × 75% × 25) - £1,200 = £1,875 - £1,200 = £675 (+£125) **Dashboard and monitoring** Monthly metrics: | Metric | Current | Target | Status | |---|---|---|---| | CAC | £1,200 | £1,000 | Monitor | | LTV | £675 | £2,000 | Low | | LTV:CAC | 0.6:1 | 3:1 | Poor | | Payback | 17 months | <12 months | Long | | ARPU | £100 | £120 | Growing | | Churn | 5% | 3% | High | | Gross margin | 70% | 75% | Good | Actions: - Increase ARPU: Implement upsell program - Reduce churn: Improve onboarding - Optimize CAC: Focus on high-efficiency channels - Improve margin: Negotiate hosting costs **Common unit economics mistakes** Mistake 1: Only CAC focus - Problem: Reduce CAC to £500, forget LTV is £600 (still unprofitable) - Fix: Monitor both CAC and LTV (ratio matters) - Impact: Avoid unprofitable growth Mistake 2: Ignore churn - Problem: Acquire 100 customers, lose 5/month - Impact: Can't build stable business - Fix: Reduce churn (highest-leverage improvement) Mistake 3: Average metrics - Problem: Average CAC £1,000, but channels range £300-3,000 - Fix: Track by channel (optimize mix) - Impact: Reallocate to efficient channels Mistake 4: Forget acquisition cost in LTV - Problem: Calculate LTV £2,000 (exclude CAC of £1,200) - Result: Think profitable when actually LTV net = £800 - Fix: Always subtract CAC from LTV - Impact: Accurate unit economics