# NetSuite Reorder Point and Preferred Stock Level Calculator > Source: https://netray.co/tools/netsuite-reorder-point-preferred-stock-level-calculator > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Work out the safety stock, reorder point and preferred stock level values to enter on a NetSuite item record. ## Category netsuite ## Erp Oracle NetSuite ## Audience - NetSuite admin - Inventory planner - Buyer ## Tool **Kind:** calculator **Currency:** $ **Inputs:** #### Average daily demand **Key:** daily_demand **Type:** number **Default:** 40 **Min:** 0 **Step:** 1 **Unit:** units/day #### Std deviation of daily demand **Key:** demand_sd **Type:** number **Default:** 12 **Min:** 0 **Step:** 0.5 **Unit:** units #### Replenishment lead time **Key:** lead_time **Type:** slider **Default:** 21 **Min:** 1 **Max:** 90 **Step:** 1 **Unit:** days #### Target service level **Key:** service **Type:** select **Default:** 0.95 **Options:** ##### 90% **Value:** 0.9 ##### 95% **Value:** 0.95 ##### 97.5% **Value:** 0.975 ##### 99% **Value:** 0.99 #### Days of demand per order **Key:** order_cycle **Type:** number **Default:** 14 **Min:** 0 **Step:** 1 **Unit:** days **Help:** How many days of demand one replenishment covers. #### Unit cost **Key:** unit_cost **Type:** number **Default:** 14.2 **Min:** 0 **Step:** 0.1 **Unit:** $ **Outputs:** #### Z score **Key:** z **Expr:** normsinv(service) **Format:** decimal #### Demand during lead time **Key:** lt_demand **Expr:** daily_demand * lead_time **Format:** integer #### Safety stock level **Key:** safety **Expr:** ceil(z * demand_sd * sqrt(lead_time)) **Format:** integer **Primary:** true #### Reorder point **Key:** rop **Expr:** ceil(lt_demand + safety) **Format:** integer **Primary:** true #### Preferred stock level **Key:** preferred **Expr:** ceil(rop + daily_demand * order_cycle) **Format:** integer #### Safety stock in days **Key:** safety_days **Expr:** safety / daily_demand **Format:** days #### Safety stock value **Key:** safety_value **Expr:** safety * unit_cost **Format:** currency **Chart:** #### Safety stock and reorder point vs lead time **Type:** line **X:** lead_time **From:** 1 **To:** 60 **Steps:** 30 **Series:** - safety - rop **Disclaimer:** Assumes normally distributed daily demand and a fixed lead time. Add lead time variability or use a larger buffer for erratic or intermittent items. ## Content **Intro:** NetSuite item records carry safety stock, reorder point and preferred stock level fields that drive replenishment suggestions and planning. This calculator gives you defensible values from demand, variability, lead time and a target service level, instead of copied numbers that go stale. **Sections:** #### How to use it **Body:** Pull average daily demand and its standard deviation from a saved search over the last 6 to 12 months of item fulfillments or sales, excluding one-off spikes. Enter the vendor lead time in days, choose a service level, and set how many days of demand one order should cover. The result gives you the three values to key into the item record. Review the chart to see how sensitive the buffer is to lead time before negotiating with the vendor. #### The formulas **Body:** Safety stock is the Z score for your service level times the standard deviation of daily demand times the square root of lead time. Reorder point is demand during lead time plus safety stock. Preferred stock level is the reorder point plus the demand covered by one order cycle, the level you want to be at after receiving a replenishment. The square root rule assumes daily demand is independent from day to day, which is reasonable for steady items. **Bullets:** - 90% service gives Z of about 1.28 - 95% service gives Z of about 1.65 - 99% service gives Z of about 2.33 - Halving lead time cuts safety stock by about 29% #### Common mistakes **Body:** Teams often use average monthly demand with a daily lead time, mixing units. Others set the same service level for every item; a 99 percent target on a slow, expensive item ties up cash for little benefit. Use ABC classes: higher service for A items and critical spares, lower for C items. Also check the item location settings, because in a multi-location setup the planning values apply per location and the totals should not be entered on the item without that context. **Cta:** Netray can compute these values across your whole item master from live NetSuite history and propose updates for human approval, instead of editing records one at a time. **Faq:** #### What is the difference between reorder point and preferred stock level? **Answer:** Reorder point is the on-hand level that triggers a new order. Preferred stock level is the target to build back up to when replenishing. The gap between them is roughly the quantity one order cycle should bring in. #### Which demand data should I use? **Answer:** Use outbound demand such as fulfillments, issues to work orders or forecasted demand for the lookback period, not purchases. Remove one-off orders and stockouts that suppressed demand, or you will understate the real need. #### What if my demand is intermittent? **Answer:** The normal distribution assumption breaks down for items that sell rarely in large lumps. For those, use a periodic review policy, a min-max based on cover days, or hold stock only against firm orders. #### How often should I recalculate? **Answer:** Review fast movers quarterly and slow movers twice a year, or whenever lead times change after a vendor switch or a disruption. Stale planning values are a common cause of both stockouts and excess stock. ## Search terms netsuite reorder point calculator, netsuite preferred stock level, netsuite safety stock level, reorder point formula, safety stock calculator service level, netsuite item record planning fields, inventory replenishment netsuite --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json