Subscription Box CAC, LTV & Break-Even Calculator
Most subscription-box calculators model one metric. CalcBee covers pricing, StoreCalcs covers profit, ChartAtlas covers unit-econ. This one unifies them — CAC, LTV, CAC payback, LTV:CAC ratio, break-even subscriber count, and a 12-month projection.
Enter per-box numbers (price, COGS, shipping, platform fees), per-customer numbers (CAC, monthly churn), and fixed costs. The tool computes contribution margin, lifetime value, payback in months, and how many subscribers you need to break even.
Educational tool only. Industry benchmarks (10–15% monthly churn, 3:1 LTV:CAC) are averages — your numbers will vary based on category, audience, and retention work.
Subscription Box Economics Calculator
Your box economics
Enter per-box and per-subscriber numbers. The right panel computes contribution margin, LTV, and payback in real time.
Per box
Cratejoy ~11.25% + $0.10. Shopify Subscriptions ~2.9% + $0.30 + 1%. WooCommerce/own ~2.9% + $0.30.
Customer acquisition + retention
Subscription-box industry avg: 10–15%/mo. Best-in-class: under 7%. Mature commerce (StitchFix S-1): ~7%.
Fixed costs + growth
Warehouse rent, software, design, owner salary.
Drives the 12-month projection. CAC × this = your monthly marketing spend.
Unit economics
The numbers an investor would ask for first.
Above 5:1 means you can scale aggressively. Consider whether you're leaving growth on the table by under-spending on acquisition.
Break-even point
You're past break-even. Each additional subscriber drops $16.78 to the bottom line every month.
12-month subscriber projection
At 25 new subs/month and 8% monthly churn from existing base.
| Month | Subscribers | Monthly profit |
|---|---|---|
| Month 1 | 163 | $1,434.32 |
| Month 2 | 175 | $1,635.62 |
| Month 3 | 186 | $1,820.15 |
| Month 4 | 196 | $1,987.90 |
| Month 5 | 205 | $2,138.87 |
| Month 6 | 214 | $2,289.85 |
| Month 7 | 222 | $2,424.05 |
| Month 8 | 229 | $2,541.47 |
| Month 9 | 236 | $2,658.90 |
| Month 10 | 242 | $2,759.55 |
| Month 11 | 248 | $2,860.20 |
| Month 12 | 253 | $2,944.08 |
The 4 numbers that determine whether your box is a business
1. Contribution margin per box
Box price minus COGS minus shipping minus platform fees. Industry rule: keep COGS at 35% or under, total variable costs at 50–60% of price, leaving 40–50% contribution margin. Below 30% contribution, no amount of scale will save you.
2. Average subscriber lifetime
1 ÷ monthly churn rate. At 10% monthly churn the avg subscriber stays 10 months. At 5% they stay 20 months. Subscription-box industry average: 10–15%/month. Best-in-class operations (snack boxes with strong unboxing, niche communities): 5–7%/month. The math is brutal — halving churn doubles lifetime and doubles LTV.
3. CAC payback (months)
CAC ÷ contribution margin per box. The target is 3 months or less for healthy subscription businesses; 12 months is the Recurly outside-edge benchmark for sustainable SaaS. Subscription boxes need faster payback because churn is higher than SaaS — payback of 6+ months at 10% churn means many subscribers never repay their acquisition cost.
4. LTV:CAC ratio
The headline VC metric. 3:1 is the sweet spot — proven economics with room to invest in scale. Above 5:1 means you may be under-spending on acquisition. Below 2:1 means every new customer is a net loss, and scaling makes the loss bigger. Subscription-box reality check: most under-investigated boxes operate at 1.5–2.5:1 and run out of cash within 18 months.
Frequently asked questions
What's the break-even point for a subscription box?
Break-even subscribers = monthly fixed costs ÷ contribution margin per box. With $800/mo fixed costs and $15 contribution margin per box, break-even is 54 subscribers. Industry benchmark for typical boxes: 250–500 active subscribers needed to break even on full operating cost (warehouse, software, design, marketing).
What's a healthy LTV:CAC ratio for subscription boxes?
3:1 is the industry sweet spot. Below 2:1 is unsustainable — every new subscriber is a net loss after acquisition cost. 3:1 to 5:1 is investable. Above 5:1 you may be under-spending on growth.
What's the average churn rate for subscription boxes?
10–15% monthly is the subscription-box industry average — meaning subscribers stay 6.7–10 months on average. Below 7% is best-in-class. Snack boxes, book subscription boxes with strong communities, and curated niches retain better than generic boxes.
How do I lower my CAC?
Three levers: (1) Improve conversion on existing traffic — better landing page, better photos, better unboxing video. (2) Lower cost-per-click on paid acquisition — narrow your targeting, kill bad placements. (3) Activate organic channels — content marketing, referral programs, influencer seeding. CAC of $15–$30 is achievable for niche boxes; $50+ is unsustainable for <$30 monthly boxes.
Should I bill annually or monthly?
Annual billing dramatically improves CAC payback (you collect 12 months upfront) and reduces churn (sunk-cost psychology keeps subscribers active). Trade-off: annual subscribers expect a discount of 10–15% off monthly equivalent, and a refund-on-cancel policy is harder to defend. Most successful boxes offer both, biasing toward annual via discount.
Track real CAC, churn, and LTV across every cohort
The calculator models economics for one assumed cohort. Ardent Seller tracks real subscribers, ties acquisition spend to specific cohorts, computes true CAC and LTV by month-of-first-purchase, and surfaces cohort retention curves — the data Procurement / VC due-diligence asks for first.
Sources & verification
- Recurly — SaaS & Subscription Industry Benchmarks (opens in new tab)
- Subscription Trade Association (SUBTA) (opens in new tab)
- Cratejoy — Subscription Box Platform Fees (opens in new tab)
- Shopify Subscriptions — Pricing (opens in new tab)
- Stitch Fix S-1 Filing (2017) — Subscription Commerce Churn Benchmark (opens in new tab)
Industry-standard benchmarks vary by category and stage. Always model with your real cohort data once you have 6+ months of history. Data current as of 2026-05-18.
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From the blog
Articles that dig deeper into the topics this tool covers.
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Cash Flow for Seasonal Sellers: How to Survive the Months When Nobody's Buying
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Revenue is up, orders are up, and somehow the bank account is not. Here is a six-symptom diagnostic for the most common margin leaks in a maker business — supplier drift, packaging creep, shipping spillover, custom-order time bleed, marketplace fee inflation, and discount habituation — with the specific report that will tell you which leak is yours.