Free tools
Inventory calculators, free and without a sign-up wall
The four calculations that decide how much stock you carry and when you reorder. Each page shows the formula, explains where every input comes from, and works through a real example — so you can check the answer rather than trust it.
No account, no email, nothing stored. All four run entirely in your browser.
Reorder point calculator
The stock level that should trigger your next order, from demand, lead time, variability and service level.
Open the calculator →Safety stock calculator
The buffer needed to hit a chosen service level, with the demand-risk and supplier-risk split shown separately.
Open the calculator →EOQ calculator
The order quantity that balances ordering cost against holding cost, plus order frequency and total annual cost.
Open the calculator →Inventory turnover calculator
Turnover ratio and days of supply from COGS and average inventory, with benchmarks by sector.
Open the calculator →How the four fit together
They are not four unrelated tools — they are the pieces of a single stock policy.
Start with turnover to see whether you have a problem at all. If days of supply looks high, use ABC analysis to find where the money is sitting. Then set reorder points and safety stock properly on the items that matter, and use EOQ to decide the quantity on each order. Review quarterly.
Each calculator page explains its own formula in full, including the assumptions it makes and the cases where it stops being the right model.
Or let the software watch the numbers for you
SmartShelfKart holds a reorder point on every product, checks it against live stock, and turns a breach into a suggested purchase order. Free on every tier during launch.