E-commerce operations calculators & Excel models
Profit, inventory and pricing tools for Amazon FBA sellers, Shopify brands and DTC operators. Every calculator exports a working Excel model with your numbers already in it.
Built for operators, not analysts
E-commerce operators make decisions daily that are arithmetic questions in disguise: should this SKU be discontinued, when do I place the next purchase order, what is the highest CPA I can pay, does this price leave enough margin. These tools answer those questions in the browser and hand you the model so you can keep answering them after the tab closes.
- Amazon FBA and marketplace sellers
- Shopify, WooCommerce and BigCommerce brands
- Etsy and creator-led commerce businesses
- Small retailers running multi-channel inventory
- Agencies and fractional CFOs serving DTC brands
Amazon FBA profit & fee calculator
Size tier, referral fee, fulfillment, storage, returns and ad spend broken into one honest per-unit P&L — plus the downloadable workbook with a live fee matrix and batch simulator.
amazon-fba-profit-model.xlsx · SKU Unit Economics · Size & Tier Fee Reference · Batch Profitability
Inventory reorder point planner
Safety stock from real demand and lead-time variability, a reorder point that reflects supplier reliability, and a downloadable purchase order generator.
inventory-reorder-planner.xlsx · Sales Velocity · Lead Time & ROP · Purchase Order
Break-even ROAS & target CPA calculator
Find the exact ROAS where paid acquisition stops losing money, the CPA ceiling for your profit target, and the spend level where diminishing returns take over.
break-even-roas-model.xlsx · ROAS & CAC Matrix · Campaign Model · Scaling Limits
DTC unit economics & cohort tracker
Enter your monthly repeat rates and see contribution-margin LTV at 12, 24 and 36 months, your true LTV:CAC ratio and the month your cohorts pay back.
dtc-unit-economics-cohort-model.xlsx · Cohort Retention Data · Cumulative LTV Curves · Unit Economics Health
Shopify product pricing matrix
Build true unit cost, derive a margin-targeted retail price, test promo, wholesale and marketplace tiers — and find the discount point where margin collapses.
product-pricing-matrix.xlsx · COGS Allocator · Pricing Scenarios · Benchmark Index
The five numbers that decide whether an e-commerce product works
- Contribution margin per order. Price minus COGS, shipping, fulfilment and channel fees. Not gross margin.
- Break-even ROAS. AOV divided by contribution margin. Below this ratio, volume makes things worse.
- Inventory turns. Annual units sold divided by average inventory. Under four turns, working capital is the constraint.
- Reorder point. Average daily demand times lead time, plus safety stock for demand and supply variability.
- CAC payback in months. The cash constraint that decides how fast you can actually grow.
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