← Walmart Labs Interview Insights
I started with peak hour throughput which felt right, but I didn't anchor on store size early enough and the interviewer kept pushing me on that.
Start by clarifying the store's characteristics (size, location, expected traffic) and then estimate peak customer flow to determine the number of registers needed to keep wait times acceptable. Use a structured, assumption-driven approach to calculate the required registers, and validate with industry benchmarks or queuing theory.
Pro tip: Focus on the peak hour, not average traffic, because registers must handle the busiest times to avoid long queues. Also, consider that Walmart is increasingly using self-checkout, so factor that into your calculation.
Ask about store size, location (urban vs. suburban), expected daily customer traffic, and the mix of full-service vs. self-checkout registers. This sets the scope for your estimation.
Calculate the number of customers arriving during the busiest hour (e.g., weekends or evenings) based on store size and location. Use assumptions like transactions per customer and average items per basket.
Estimate how many customers a single cashier can process per hour, considering scanning speed, payment method, and customer interactions. Typical throughput is 20-30 customers per hour for full-service lanes.
Divide peak customer flow by register throughput to get the minimum number of registers needed. Add a buffer for breaks, shift changes, and unexpected rushes.
Compare your estimate with industry benchmarks (e.g., Walmart's typical store has 10-20 registers) and consider factors like self-checkout adoption, space constraints, and labor costs to refine the number.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.