A distribution warehouse must decide how much of every product it will keep in every storage zone each week. These decisions determine the use of space, the handling workload and whether demand is met. This study shows how linear programming (LP), a core technique of Operations Research (OR), can help with that decision. We formulate a warehouse space allocation model for an illustrative regional distributor with four product families and three storage zones. We maximize net weekly contribution subject to zone capacity, demand limits, minimum service levels and product–zone compatibility; we solve it as an integer linear programme and the optimal plan is compared with a rule-of-thumb plan. The optimal plan earns 1,095,300 currency units (CU) per week compared to 1,094,100 CU for the rule, a difference of 0.11%. The more informative result is the sensitivity analysis: each additional racking position is worth about 1,500 CU per week up to 400 and about 1,220 CU per week after that. The data are illustrative, and so this study demonstrates a method and does not provide evidence about any real warehouse.