This guide covers many of the ways to replenish inventory for sellers who buy products from suppliers and resell them.
When stock runs low, create a purchase order (PO) to reorder, and Katana handles the tracking and updates your inventory automatically.
Before you start
To add a product to a purchase order, it needs to have Buy enabled on its product card. If you imported your products from Shopify, this is usually already turned on.
Tip: You can also set a default supplier and default purchase price for each product (under the Supply details tab). This auto-fills these fields when creating a PO.
Option 1: Reorder from the Stock screen
Best for: Reviewing inventory and quickly reordering products that are running low.
Understanding your stock levels:
In stock – Physically in your warehouse
Committed – Reserved for open sales orders
Expected – On open purchase orders, coming from suppliers
Safety stock level – Your reorder threshold (set per product)
Calculated stock – Your stock health at a glance. Formula: In stock − Committed + Expected − Safety stock. If negative (highlighted in red), it's time to reorder.
How to reorder:
Go to Stock screen → Inventory tab and select a specific location. (Safety stock and Calculated stock columns don't appear if viewing multiple locations)
Look for products with negative Calculated stock (highlighted in red).
Click the +Buy button at the end of the row.
A new PO opens with the product pre-filled. Add supplier, expected arrival, quantity, and price.
Click Save.
Bulk reorder:
Katana notifies you if other products from the same supplier need restocking. Click Add them... at the bottom of the PO.
You can also bulk select items on the Stock screen (e.g., filter by default supplier and negative Calculated stock) to create a PO for the selected items.
Option 2: Create a purchase order manually
Best for: When you know exactly what you need to order, or when ordering multiple products from one supplier.
How it works
Click + Create → Purchase order from the global navigation, from the Buy screen, or directly from a sales order (if an order shows Not available → open SO → + Buy).
Select a supplier: Choose from existing suppliers or type a new name to create one
Set the expected arrival date: When you expect the goods to arrive.
Add products: Click in the item field and select products. For each, enter:
Quantity to order
Price per unit (defaults to your set purchase price)
Tax rate if applicable
(Optional) Add additional costs like shipping or customs fees. These can be distributed by value across products for accurate landed costs.
(Optional) Use the Additional info section to add notes for your supplier or internal reference.
Tip: Click Print or the email icon to send the PO directly to your supplier from Katana.
Option 3: Use replenishment suggestions (Plan screen)
Best for: Automating reorder decisions once you have sales history in Katana.
The Plan screen uses your stock levels, open orders, and sales patterns to calculate suggested order quantities and when to place them, so you can reorder before running out.
How it works
Go to Plan screen → Replenishment tab.
Katana shows products that need restocking with:
Stockout date: When the product is projected to run out
Suggested order qty: Recommended amount based on demand and MOQ
Suggested order by: Latest date to place an order based on lead time
Purchase cost: Estimated cost for the suggested order
Click Buy on any row to create a pre-filled purchase order.
Tip: Add lead times and MOQ to your product variants (in the Supply details tab on the product card).
What happens after you create a PO
The PO appears in your Buy screen with status Not Received, and the ordered quantities show as Expected in your Stock screen. Any sales orders waiting on that stock update from Not available to Expected with the expected arrival date.
When goods arrive
Go to the Buy screen and find your PO.
Click the Delivery status column (or open the PO card) and select:
Receive all – if everything arrived
Receive some... – for partial deliveries
Received items are added to In stock and are available to sell.
Quick summary: Which method to best?
Reviewing inventory?
Use the Stock screen to see everything at a glance and reorder with one click.
Know what you need?
Use + Create → Purchase order.
Shopify order came in and you're out of stock?
Buy directly from the sales order.
Want automated suggestions?
Build your sales history, and use the Plan screen.
Your feedback is invaluable. Let us know your thoughts on this article or anything in Katana you'd like to see improved: [email protected]