Inventory & COGS for E-commerce Sellers
An 18-lesson course for online sellers: SKU master data, purchase receipts, FIFO cost of goods sold, margin reports and reorder points.
Articles18
Lesson 01 · Meet Juniper Goods and the COGS-first workbookOne candle studio, two channels, and a workbook that answers what did we actually earn (Stage 1 · Foundations; 25-35 min)Published 2026-09-29Lesson 02 · The SKU master: five candles, one naming schemeStable codes, one retail price per product, margin math you can trust (Stage 1 · Foundations; 30-40 min)Published 2026-09-29Lesson 03 · The material master and what you actually ownEight materials, their units and suppliers, and a purchased-quantity SUMIF (Stage 1 · Foundations; 30-40 min)Published 2026-09-29Lesson 04 · Recipes: the bill of materialsOne row per material per SKU, with names filled in by VLOOKUP (Stage 2 · Recipes and Purchases; 30-40 min)Published 2026-09-29Lesson 05 · Purchases and FIFO cost layersEvery buy is a priced layer; production drains the oldest layer first (Stage 2 · Recipes and Purchases; 35-45 min)Published 2026-09-29Lesson 06 · What did we last pay? Latest unit costFind the most recent purchase date, then price the BOM at today's costs (Stage 2 · Recipes and Purchases; 30-40 min)Published 2026-09-29Lesson 07 · Rolling up the true unit cost of a candleSUMIF the recipe lines into one cost per SKU, then read the margin (Stage 3 · Production and Stock; 30-40 min)Published 2026-09-29Lesson 08 · Production batches: from wax to finished goodsEach completed pour is a costed layer of sellable stock (Stage 3 · Production and Stock; 30-40 min)Published 2026-09-29Lesson 09 · Stock on hand: produced minus sold minus shrinkSUMIFS across journals, lifetime counts, and the shrink bridge (Stage 3 · Production and Stock; 30-40 min)Published 2026-09-29Lesson 10 · The channel sales logOne row per order, priced from master data, with fees typed in (Stage 4 · Sales and FIFO COGS; 30-40 min)Published 2026-09-29Lesson 11 · FIFO COGS: draining layers oldest-firstWrite each order's draw against a batch layer, including split draws (Stage 4 · Sales and FIFO COGS; 35-45 min)Published 2026-09-29Lesson 12 · Per-sale profit: COGS, fees, and marginOne SUMIF lifts the draw log onto every order row (Stage 4 · Sales and FIFO COGS; 30-40 min)Published 2026-09-29Lesson 13 · Margin by SKU and channelA SUMIFS matrix that filters SKU, channel, and period in one formula (Stage 5 · Margin Analysis; 35-45 min)Published 2026-09-29Lesson 14 · Etsy vs Shopify: channel economicsCOUNTIFS the orders, then compare what each channel really charges (Stage 5 · Margin Analysis; 30-40 min)Published 2026-09-29Lesson 15 · Pricing: planned margin vs actual marginCompare the SKUs sheet's plan against what September actually earned (Stage 5 · Margin Analysis; 30-40 min)Published 2026-09-29Lesson 16 · Cycle counts and shrinkageVariance times unit cost, and the bridge back into stock (Stage 6 · Count, Shrink, and Reorder; 30-40 min)Published 2026-09-29Lesson 17 · Reorder points: safety stock plus lead timeTurn September's sales rate and a 14-day cure into a make-now number (Stage 6 · Count, Shrink, and Reorder; 35-45 min)Published 2026-09-29Lesson 18 · Holiday readiness reviewWalk the whole model once, then take the workbook home (Stage 6 · Count, Shrink, and Reorder; 30-40 min)Published 2026-09-29