We manage about 1,200 SKUs with 28–35 day supplier lead times, and my Excel ROP formula (avg daily demand × lead time + z × stdev of lead-time demand) cut stockouts 14% but carrying costs are still high; I want something that handles seasonality, MOQs, and order batching without a full ERP. Any recs on lightweight tools or templates — bonus if it plugs into Shopify and can simulate cost trade-offs by SKU?
We moved about 1.2k SKUs to Inventory Planner, set seasonality by collection and vendor MOQs/case packs, and used its service-level slider to “simulate” buys; that trimmed safety stock about 15–20% without extra stockouts (https://www.inventoryplanner.com/).
What worked for us was piping Shopify into Cogsy (https://www.cogsy.com), turning on weekly seasonality and vendor-level MOQs/case-pack rounding, then using its what‑if service levels to simulate buys before placing POs. Caveat: really spiky SKUs still needed manual overrides; for those I keep a tiny Croston sheet to set safety stock and let Cogsy handle the batching.