From stock in pallets to building size: positions, levels, aisles and square feet for each aisle type, a module plan and how many dock doors avoid peak-hour queues.
Pre-sizing and estimating tool: results do not replace design, calculations or reports signed by a licensed professional, nor verification against the applicable codes and standards.
To scale: racks in blue, working aisles in light grey and cross aisles at the ends. A simple parallel-block layout: a good starting point, not necessarily the best layout for your site.
Same stock, same building: each truck type changes aisle width and the levels it can reach.
Storage (racks, aisles and cross aisles) plus support areas, for the same positions.
Wait in the peak hour from the M/M/c queue model; the dashed line is the acceptable wait entered.
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It turns stock in pallets into warehouse size: pallet positions needed, rack levels, bays, aisles, storage area, support areas and total square footage, and works out how many dock doors avoid peak-hour queues. It compares counterbalanced, reach truck and turret (VNA) aisles and draws the plan of one module. Use it for a new building study, an expansion or to check a design.
Peak stock is 2,400 pallets; at 85% target occupancy the warehouse needs 2,824 positions. With a reach truck (9 ft aisle), a 32 ft clear building takes 5 levels, giving 283 bays of 2 pallets in 9 aisles of about 127 ft. The 157 × 153 ft block covers 24,008 ft²; with 30% support space the total is 31,210 ft², or about 11 ft² per position.
Because a full warehouse jams: there is no free slot to receive, pick and reshuffle, and putaway time climbs. With random locations, 85 to 90% is the practical ceiling. In the example, 85% adds 424 spare positions on top of the 2,400 pallets.
A narrower aisle stores the same stock in less space, but the truck costs more and needs a flat floor and trained operators. In the example, counterbalanced trucks (12 ft aisles and only 4 levels with 20 ft of lift) need 48,803 ft²; reach trucks 31,210 ft²; turret trucks (6 ft aisles) 25,843 ft². Weigh the area gap times your cost per square foot against the price and upkeep gap between trucks.
Paste the list with code, average stock and peak stock of each SKU, in pallets. With dedicated slotting, each SKU reserves its maximum (sum of maximums). With random slotting in the WMS, since peaks do not coincide, the sum of averages plus √Σ(max − average)² is enough: in the sample list, 2,197 pallets instead of 2,810, 22% fewer.
The calculator takes truck arrivals in the peak hour (daily average × 1.5 in the example) and each truck’s time at the door, and applies the M/M/c (Erlang C) queue to find the fewest doors with an average wait of 15 min or less. In the example, 18 inbound and 24 outbound trucks a day over 10 hours, at 60 min each, need 5 receiving and 6 shipping doors.
The layout is parallel blocks with equal aisles, with no columns, interior docks, mezzanines or egress routes: a good starting point, not the optimum. Aisle widths and lift heights are typical and should come from the truck maker. Racking must be designed to ANSI MH16.1, and the building must meet NFPA 13 and the locally adopted fire and building codes.
Important notice: Indus Metrics tools produce estimates and pre-sizing results from the data you enter and from published engineering methods. They do not replace design, calculations or reports signed by a licensed professional engineer (PE), nor verification against the applicable codes, standards and regulations, such as OSHA rules and the ASME codes. Material and fuel properties vary: check manufacturer data or your own process analyses before deciding. By using this site you agree to the Terms of Use.
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