# MRP Planning Terms Glossary (Searchable Reference Table) > Source: https://netray.co/tools/mrp-planning-terms-glossary-reference > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer A searchable glossary of the terms MRP planners use every day, with the plain meaning and how each term shows up in a planning run. ## Category supply-chain ## Audience - Production planner - Materials manager - ERP consultant ## Tool **Kind:** worksheet **Mode:** reference **Columns:** #### Term **Key:** term **Type:** text #### Short form **Key:** abbr **Type:** text #### Meaning **Key:** meaning **Type:** text #### Where a planner sees it **Key:** use **Type:** text **Rows:** #### Gross requirements **Abbr:** GR **Meaning:** Total demand for an item in a time bucket before any supply is considered **Use:** Top row of the MRP record; from forecasts, customer orders and parent planned orders #### Scheduled receipts **Abbr:** SR **Meaning:** Supply already committed, such as open purchase orders and released production orders **Use:** Second row of the MRP record, dated to expected receipt #### Projected available balance **Abbr:** PAB **Meaning:** Expected on-hand stock at the end of a bucket after demand and supply **Use:** Row that triggers a new order when it falls below zero or safety stock #### Net requirements **Abbr:** NR **Meaning:** The shortage left after on-hand stock and scheduled receipts are applied to gross requirements **Use:** Drives the size and date of a planned order #### Planned order receipts **Abbr:** POR **Meaning:** Quantity MRP proposes to be received to cover net requirements **Use:** Shown by lot size rule; becomes a planned order in the system #### Planned order releases **Abbr:** PORel **Meaning:** The same planned orders shifted earlier by the lead time **Use:** The date a buyer or shop must start the order #### Lead time offset **Abbr:** LT **Meaning:** Time subtracted from the need date to get the order release date **Use:** Item master lead time fields, routing times, vendor lead time #### Safety stock **Abbr:** SS **Meaning:** Buffer quantity planned to remain on hand to absorb demand or supply variation **Use:** MRP treats stock below this level as a shortage #### Safety lead time **Abbr:** SLT **Meaning:** Extra days added so supply arrives before the need date **Use:** Alternative to safety stock when timing is the risk #### Lot sizing rule **Abbr:** LS **Meaning:** Rule that converts net requirements into order quantities **Use:** Item planning parameters such as lot for lot, fixed or periodic quantity #### Low level code **Abbr:** LLC **Meaning:** Lowest BOM level at which an item appears; MRP plans an item only after all its parents **Use:** Calculated at BOM change or net change run start #### Bill of material **Abbr:** BOM **Meaning:** Structured list of components and quantities needed to make one parent **Use:** Explosion step that converts parent orders into child gross requirements #### Explosion **Meaning:** Converting planned parent orders into dependent component demand through the BOM **Use:** Core MRP processing step each run #### Netting **Meaning:** Offsetting gross requirements against available stock and scheduled receipts **Use:** Core MRP processing step each run #### Pegging **Meaning:** Trace from a supply or requirement back to the demand that created it **Use:** Pegging or where-used-by-demand screens and reports #### Net change planning **Abbr:** NC **Meaning:** Run that replans only items with changes since the last run **Use:** Daily or intra-day planning runs #### Regenerative planning **Meaning:** Run that recalculates all planned items from scratch **Use:** Weekly or after major data changes #### Planning horizon **Meaning:** How far into the future MRP plans **Use:** Run parameter; must cover cumulative lead time of the longest item #### Time bucket **Meaning:** Unit of time used to group demand and supply, such as day or week **Use:** Planning calendar and MRP record column width #### Demand time fence **Abbr:** DTF **Meaning:** Near-term window inside which forecast is ignored and only firm orders count **Use:** Item master planning time fence fields #### Planning time fence **Abbr:** PTF **Meaning:** Window inside which MRP does not automatically change or create orders **Use:** Item master planning time fence fields #### Firm planned order **Abbr:** FPO **Meaning:** Planned order protected from automatic MRP changes **Use:** Planner action to freeze a proposal #### Action message **Meaning:** System suggestion to release, expedite, defer, cancel or change quantity of an order **Use:** Exception list the planner works through each day #### Dependent demand **Meaning:** Demand for an item calculated from demand for its parent **Use:** Component requirements created by explosion #### Independent demand **Meaning:** Demand from outside the plan such as customer orders, forecasts and service parts **Use:** Entered at end item level #### Master production schedule **Abbr:** MPS **Meaning:** Plan of what end items will be built and when, which feeds MRP **Use:** Planned at end item or key item level #### Available to promise **Abbr:** ATP **Meaning:** Uncommitted supply that sales can promise to new orders **Use:** Order promising and availability checks #### Yield or scrap factor **Meaning:** Allowance that increases the gross quantity to cover expected losses **Use:** BOM component scrap and item yield fields #### Phantom item **Meaning:** Subassembly that is exploded through rather than stocked or ordered **Use:** Item type or BOM flag in most ERPs #### Order multiple **Meaning:** Increment to which order quantities are rounded up **Use:** Purchasing or lot size rounding fields **Notes:** Term names vary slightly between APICS style material and individual ERP products. Field names in your own system may differ, so check your vendor documentation. ## Content **Intro:** MRP conversations go wrong when two people use the same word for different things. This table gives the standard meaning of each term and shows where the planner meets it in an ERP planning run. **Sections:** #### How to use the glossary **Body:** Type part of a term in the search box, or scan the Where a planner sees it column to learn which screen or field the term maps to. The table exports to Excel or PDF, so you can attach it to a new planner's onboarding pack or an ERP implementation workbook. Terms are ordered roughly in the sequence an MRP run processes them: demand, supply, balance, orders, then controls. #### The MRP record in one paragraph **Body:** Every MRP record is the same grid: gross requirements, scheduled receipts, projected available balance, planned order receipts and planned order releases per time bucket. The balance starts at on-hand stock. Each bucket adds receipts and subtracts demand. If the balance would drop below zero or below safety stock, MRP creates a planned order receipt in that bucket sized by the lot rule, then offsets it earlier by the lead time to get the release. #### Terms people confuse **Body:** Several pairs cause repeated mistakes in planning reviews. **Bullets:** - Gross vs net requirements: net is after stock and receipts, gross is before. - Scheduled receipt vs planned order: a receipt is committed, a planned order is only a proposal. - Demand time fence vs planning time fence: one controls which demand counts, the other controls whether MRP may change orders. - Safety stock vs safety lead time: quantity buffer versus timing buffer. - Net change vs regenerative: partial replan versus full replan. **Cta:** If your planners still translate these terms between spreadsheets and the ERP, we can show how an AI assistant answers planning questions directly from your live MRP data. **Faq:** #### Is gross requirement the same as demand? **Answer:** Gross requirement is the total demand placed on an item in a time bucket, including dependent demand created by parent orders and independent demand from customers or forecasts. It is demand before any stock or receipts are used to cover it. #### What is the difference between a planned order and a scheduled receipt? **Answer:** A planned order is a proposal created and changed freely by MRP. A scheduled receipt is a committed order such as a released shop order or a confirmed purchase order. MRP counts both as supply but only changes planned orders automatically. #### Why does low level code matter? **Answer:** MRP must know all demand for an item before it nets that item. The low level code sequences the run so a component is planned only after every parent that uses it, even if the component appears at several BOM levels. #### Do all ERPs use the same MRP terms? **Answer:** The concepts are common but the field names differ. For example some systems call the planning time fence a frozen period, and some split lot sizing into several procedure codes. Use this table for meaning and your vendor guide for field names. ## Search terms mrp terminology, mrp glossary, mrp terms and definitions, gross requirements vs net requirements, planned order vs scheduled receipt, mrp planning terms, projected available balance definition, low level code meaning --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json