Labour, productivity and fulfilment economics

What drives store labour cost

Store labour cost is hours multiplied by the loaded cost of an hour: wage plus taxes, benefits, and night or weekend premiums. The hours come from a few drivers you can measure yourself:

• Volume: cases delivered, items sold, online orders filled.
• Productivity: cases restocked or order lines picked per hour, which depend on layout, shelf height, backroom distance and how busy the aisles are.
• Timing: work done overnight or on weekends costs more an hour where premiums apply.
• Turnover: hiring and training replacements, and the hours lost while new staff learn.

For the US, the Bureau of Labor Statistics publishes employment, hours and earnings for food and beverage stores.^[20] Your own payroll is better than any average: use it.

Restocking and stock rotation

Restocking hours a week can be written as:

restocking hours = cases delivered a week ÷ cases restocked per hour

Rotation adds time per cabinet or bay, and its pay-off shows up in waste: items written off past their date. Take both from your own records: time a sample of shifts and read the write-off report for the categories in question.

Gaps have a cost too: a shopper who doesn't find a product may buy something else, go elsewhere, or buy nothing. The size of that loss differs by store and category; measure on-shelf availability before and after a pilot rather than borrowing a figure. Robots that only detect gaps add tasks; robots that restock remove them.^[5][1]

Picking and fulfilment

picking cost per order = (pick + pack + hand-over hours) × loaded hourly cost ÷ orders

• Picking from store shelves uses stock you already hold. Hours scale with orders, and pickers share the aisles with shoppers.^[7][1]
• Picking from an automated grid lowers hours per order but adds construction, a separate stock-holding and fixed capacity. It pays when it runs near capacity, and a stoppage takes all of its capacity offline at once.^[12][11]

How much of your sales go online decides which side wins. For the US, the Census Bureau publishes quarterly e-commerce sales; your own order data is the figure that counts.^[21]

What a robot really costs

• Hardware: purchase, lease or a monthly robot-as-a-service fee.^[13]
• Installation and store changes: charging points, Wi-Fi, mapping, cleared routes.
• Software, maintenance and support, often per robot per month.
• Staff time to look after it: charging, clearing jams, finishing tasks it couldn't.
• Downtime: how the work gets done when it isn't running.

Few vendors publish prices. Ask for every line above in writing before you compare.

The payback model

hours freed a week = task hours today × share the robot takes − hours looking after it labour value a month = hours freed a week × loaded hourly cost × 52 ÷ 12 net saving a month = labour value a month − robot cost a month payback (months) = upfront cost ÷ net saving a month

Two rules keep it honest. First, take “share the robot takes” from a timed pilot in your own store, not from a brochure. Second, count availability and waste gains only once the pilot has measured them, and add them as separate lines so you can see what the case rests on.

Calculator

Where to find the figures

• Hours and wages: your payroll and rota; for US context, BLS data for food and beverage stores.^[20]
• Online share: your order data; for US context, Census e-commerce reports.^[21]
• Industry research: trade bodies such as FMI publish operations and workforce research.^[22]
• Robot performance: a timed pilot in your own store. Treat vendor figures as the vendor's own.^[4]

Before the pilot, agree the measures with the vendor using the buyer's checklist.