About this Reorder Point Calculator
A reorder point helps decide when available stock is low enough to place the next purchase order before lead-time demand causes a stockout.
Who this calculator is for
- Ecommerce operators estimating order, fulfillment, and shipping economics.
- Marketplace sellers comparing carrier, packaging, pricing, and return assumptions.
- Operations, finance, and inventory teams documenting transparent planning math.
When to use it
- Model shipping, handling, free-shipping, returns, or reorder scenarios from your own rates.
- Compare conservative and optimistic assumptions before changing pricing or inventory policy.
- Document the formula behind a fulfillment decision without exposing private order data.
How to use this calculator
- Enter your own costs, rates, volumes, dimensions, and policy assumptions.
- Adjust optional fields to match the SKU, channel, packaging, or planning period.
- Review the primary result and supporting outputs before making pricing, shipping, or inventory changes.
Key assumptions
- All rates, fees, costs, order values, demand volumes, and policy targets are user-entered assumptions.
- The calculator uses transparent deterministic formulas and does not fetch live carrier, marketplace, warehouse, tax, or provider rates.
- Results are planning estimates and should be checked against your carrier terms, marketplace fees, inventory system, and accounting policy.
- Inputs are processed locally in your browser.
Accuracy and testing
Review formula sources, default test cases, assumptions, unit handling, rounding rules, and changelog for this calculator.
How this calculator works
Demand during lead time = average daily demand x supplier lead time. Reorder point = demand during lead time + safety stock.
Demand during lead time = average daily demand * lead time days. Reorder point = demand during lead time + safety stock.
Inputs explained
Average daily demand
Expected units sold or consumed per day for the SKU being modeled.
Supplier lead time
Days between placing a replenishment order and having sellable stock available.
Safety stock
Extra units kept on hand to cover demand spikes, delays, receiving issues, or forecasting error.
Understanding your results
Reorder point is the inventory level where a new order should be placed under the assumptions entered. If actual demand or lead time is volatile, increase safety stock or model a more conservative case.
Example scenarios
Planning example
Selling 18 units per day with a 12-day supplier lead time and 45 units of safety stock gives a reorder point of 261 units.
Key Features
- User-entered rates and costs only
- Transparent formulas
- Local browser calculation
Tips & Best Practices
- Use recent invoices, label history, return reports, and order data when available.
- Run a conservative scenario with higher costs or lower demand before changing customer-facing pricing.
- Separate carrier cost, handling cost, inventory cost, and refund loss so the driver of the result stays visible.
Glossary of Terms
- Dimensional weight
- A billable-weight method based on package volume divided by a carrier divisor.
- Billable weight
- The weight used for pricing, often the greater of actual weight and dimensional weight.
- Contribution
- Gross profit remaining after a specific cost, such as shipping or returns, is subtracted.
- Safety stock
- Extra inventory kept above expected demand to reduce stockout risk during lead time.