Inventory Calculators
Five browser-based calculators for the maths every inventory and ops team runs regularly — safety stock, reorder points, order quantities, and working-capital ratios. Each one ships with the formula, a worked example, and links to the relevant glossary entries.
Safety Stock Calculator
Compute the buffer that protects against demand and supply variance. Z × σ × √LT simple formula, or the full formula with lead-time variability.
Open safety stock calculatorReorder Point Calculator
Find the stock level at which to trigger the next PO. ROP = (D × LT) + Safety Stock — with days of cover at the trigger as a sanity check.
Open reorder point calculatorEOQ Calculator
Economic Order Quantity using √((2 × D × S) / H). Outputs optimal order size, orders per year, cycle time, and total annual inventory cost.
Open EOQ calculatorDays Inventory Outstanding
DIO = (Average Inventory / COGS) × Days in Period. Annual, quarterly, or monthly. Tells you how long stock sits before it sells.
Open DIO calculatorInventory Turnover
Turnover = COGS / Average Inventory. With industry benchmarks built in — apparel, beauty, electronics, furniture, food, industrial.
Open turnover calculatorMore calculators coming
Next on the build queue: GMROI, ABC analysis, lead-time variability, freight-cost break-even, and a SKU rationalisation scorer. If there's a calculation you run regularly in a spreadsheet and would prefer to use here, let us know.
Free templates and resources
Beyond the calculators — the templates and diagnostics scaling brands actually use.