Warehouse Capacity & Peak Readiness Calculator

How this works: your warehouse's real daily order capacity is set by whichever stage — picking, packing, or despatch — has the lowest throughput, not the average across all three. Only direct staff (total headcount minus the indirect % you set) are counted toward throughput; indirect staff — team leads, support, quality checks — still cost money but don't add picking, packing, or despatch capacity in this model. Picking capacity is calculated in lines per day and converted to order-equivalents using your average lines-per-order figure, since picking is usually measured in lines, while packing and despatch are usually measured in orders. This is a planning model based on rates sustained across a full shift — it doesn't account for breaks, shift handovers, pick-path inefficiency, congestion at pinch points, absenteeism, inbound and putaway capacity, returns processing, or physical storage space, all of which can be the real constraint in a given operation. Use it to identify which stage to investigate first, not as a guaranteed output number.

On fatigue: the rates you enter are usually the rate someone hits early in a shift, working at full pace. Genuine warehouse fatigue research consistently finds output declining over the course of long or intense shifts, though the exact size of the drop varies hugely by task, shift length, and individual conditions — there's no single number that applies cleanly to every operation, so this is left as your own judgement call rather than a borrowed statistic. The slider applies as a flat average reduction across the whole shift, which is a simplification of what's really a progressive decline through the day — treat it as a way to sense-check how sensitive your capacity is to fatigue, not as a precisely modelled curve.

On labour cost: the wage figure uses the UK National Living Wage of £12.71/hour (workers aged 21+, effective from 1 April 2026, GOV.UK). This is a legal floor, not a realistic warehouse pay rate — most fulfilment operators pay above it, especially for night shifts, peak premiums, and supervisory roles, so treat this total as a minimum reference point, not an estimate of actual payroll. Employer National Insurance is shown as an approximate 15% addition; this is a simplification, since real employer NI is calculated against an annual £5,000 per-employee threshold rather than cleanly per shift, so the true figure will differ from this estimate, particularly for part-time or lower-hours staff. Indirect staff are included in headcount and cost, but not in the capacity calculation.