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4 tools liveHow much should I order?
EOQ Calculator
Find the order quantity that minimises total inventory cost — balancing ordering and holding costs automatically. Includes a sawtooth inventory chart.
Open calculator →When should I reorder?
Reorder Point Calculator
Calculate the exact inventory level that triggers your next order — accounting for demand variability and lead time uncertainty to prevent stockouts.
Open calculator →How much buffer inventory do I need?
Safety Stock Calculator
Calculate the safety stock that protects your target service level — based on demand variability, lead time, and your chosen in-stock rate.
Open calculator →How long does replenishment take?
Lead Time Calculator
Calculate total lead time from its components — order processing, production, and transit. See a visual breakdown and how lead time flows into reorder point and safety stock.
Open calculator →Coming Soon
Supply Chain Guides
Understand the theory behind each calculator before you use it.
Frequently Asked Questions
What is supply chain optimisation?
Supply chain optimisation is the process of improving the efficiency and cost-effectiveness of each stage in your supply chain — from sourcing raw materials through to delivering the finished product. Calculators like EOQ and reorder point are foundational tools used in this process.
Are these calculators free to use?
Yes. All calculators on this site are free with no account or subscription required. They run entirely in your browser using standard industry formulas.
Which calculator should I start with?
Start with the EOQ Calculator — it answers the most fundamental inventory question: how much to order at once. Then use the Reorder Point Calculator to determine exactly when to place each order.
Do the calculators account for seasonality?
The current calculators use average annual or daily demand figures and suit relatively stable demand patterns. For highly seasonal products, run the calculations separately for each season using the appropriate demand rate for that period.