预计采购量 (anticipated quantity of purchase) 可以用英文表示为 "expected quantity of purchase" 或 "projected quantity of purchase"。这个表达来源于商业用语，用于描述一个公司或组织未来某段时间内预计购买的数量。
下面是一些例句：
Can you provide an estimate of the expected quantity of purchase for the next quarter? (你能提供下一季度预计采购量的估计吗？)
According to our projections, the projected quantity of purchase for this product is expected to increase by 15% next year. (根据我们的预测，明年这个产品的预计采购量预计将增长 15%)