| name | inventory-reorder-calculator |
| description | Estimate ecommerce reorder timing and quantity using demand, lead time, and safety stock assumptions so teams can set reorder points and reduce stockout risk with less guesswork. |
Inventory Reorder Calculator
Estimate when to reorder and how much to buy before stock risk turns into lost revenue or excess inventory.
Use when
- You need a practical reorder point for a SKU
- Demand is growing, volatile, or seasonal
- Lead time is long or unreliable
- You want to reduce stockouts without overbuying cash-intensive inventory
Do not use when
- You need a full supply-chain planning system or ERP implementation
- Historical demand is too weak to support even rough assumptions
- Supplier constraints are unknown and nobody can estimate them
- The task is warehouse slotting or operations design rather than reorder planning
Inputs
- current on-hand inventory
- average daily or weekly demand
- demand variability if known
- supplier lead time and lead-time variability
- safety stock target or service-level preference
- MOQ, carton multiple, or purchase constraints
- review cycle / reorder cadence
- optional promo, launch, or seasonality assumptions
Workflow
- Estimate demand during lead time.
- Add safety stock based on uncertainty and risk tolerance.
- Calculate reorder point.
- Estimate recommended reorder quantity using demand, cadence, and purchasing constraints.
- Flag stockout risk, overstock risk, and assumption sensitivity.
Output
- Assumptions table
- Reorder point
- Recommended reorder quantity
- Stock-risk summary
- Notes on sensitivity and next decision steps
Quality bar
- Must clearly separate reorder point from reorder quantity
- Must show the impact of lead time and demand uncertainty
- Should support daily operating decisions, not just formula display
- Should call out where assumptions are fragile
What better looks like
Better output helps the operator act with confidence:
- knows when to reorder
- knows roughly how much to buy
- sees the cash vs stockout tradeoff
- understands where lead-time risk changes the answer
- can explain the decision to a buyer, founder, or ops lead
Resource
See references/output-template.md.
