Knowledge

Knowledge hub. Articles on purchase planning, demand forecasting, and inventory management.

One reorder point of 240 units against lead-time demand: 63 units off-season, 525 units at the peak
·17 min read

One reorder point for every product: why it works at 50 SKUs and quietly breaks at 2,000

How did you set your minimum stock: from the formula or by gut? We checked what Base.com and the mainstream Polish ERPs actually calculate, why one threshold for all SKUs fails, and what it costs.

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Master data — a product record turned into a purchasing decision: how much to order and when
·6 min read

Master data: what it is and why every purchase plan is guessing without it

A forecast tells you how much you'll sell. But between the forecast and the order stand a few boring numbers: lead time, MOQ, case pack, purchase price. That's master data — the least glamorous part of purchase planning, and the part that decides whether the plan can be executed.

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ABC analysis — Pareto curve with products split into classes A, B and C
·7 min read

ABC Analysis in E-commerce: Which Products Actually Keep Your Store Alive?

What is ABC analysis and how do you split your products into A, B and C classes? The 80/20 method step by step, an Excel example with a free template, pitfalls and FAQ.

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Sales seasonality — demand chart for a desk fan peaking in July at 420 units, with the order date on 20 May given a 6-week lead time
·12 min read

Sales seasonality: what it is and how it wrecks your stock levels

Seasonality is a repeating demand pattern that comes back at the same time every year. How to calculate a seasonal index in a spreadsheet, why a July peak means a May order, and the five pitfalls that break those numbers.

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What is a SKU — one product split into six SKU codes (3 sizes × 2 colors)
·7 min read

What is a SKU? SKU code and SKU number guide for small businesses

A SKU is a unique code you assign yourself to every product variant. How it differs from an EAN, how to build a good code, real examples and the most common mistakes — in plain English, for micro and small businesses.

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Line chart: sales grow from 15 to 35 units/day, yet the 90-day average of 25/day tells you to order 750 units against real demand of ~1,150 — 35% short.
·6 min read

A 30-day average is not a forecast. Why rolling averages quietly wreck your inventory

The most common way to plan purchasing — a 30/60/90-day average times days to delivery — isn't wrong occasionally, it's wrong systematically: it lags the trend, can't see the season and misleads on intermittent demand. We show each case with numbers.

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Anatomy of safety stock: the formula SS = z × σ × √(L + R) broken into three components — service level, variability and risk horizon.
·6 min read

Safety stock: what it is, how to calculate it, and why most companies stick with 'days of cover' anyway

Safety stock is a buffer against demand and supply variability — and there's an elegant formula to compute it. So why do most companies stick with 'days of cover' anyway? Because simplicity makes sense — until it starts to cost.

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What did your last stockout cost you? And if you don't know — that doesn't mean it was zero.
·3 min read

What did your last stockout cost you?

A stockout has at least three hidden costs — lost margin, a lost customer and a marketplace ranking penalty. And if you don't know what your last one cost you, that doesn't mean it cost zero.

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Base Expo 2026 main stage at the Polish History Museum in Warsaw
·4 min read

We were at Base Expo 2026. One topic came back in every panel — and it wasn't technology

We went to listen to what Polish e-commerce is living with. The thread that came back most often wasn't technology or marketing — it was stockouts, and processes nobody had put in order.

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