How to handle a supplier that ships late

Separate the promise from the pattern

A supplier might quote a 14-day lead time but actually take 21 days more often than not. If you plan against the quoted number, you will run out of stock before the next shipment lands. Look at your last several purchase orders for that supplier and check order date against the date stock actually arrived, not the date they said it would arrive.

Adjust the inputs, not the process

Once you know the real lead time, update it for that supplier so every future order-by date and reorder point is based on reality. If the lateness is inconsistent rather than a fixed extra few days, add safety days instead of or in addition to extending the lead time. Safety days absorb the unpredictability; a longer lead time absorbs a consistent delay.

Decide if the supplier stays

A supplier who is a few days late occasionally is a planning problem you can solve with numbers. A supplier who is late every single time, or late by a growing margin, is a sourcing problem. At some point the fix is a backup supplier or a different primary, not more safety stock, because safety stock just ties up more cash to cover someone else's inconsistency.

Watch the SKUs most exposed to the delay

Fast movers on a late supplier run out faster than slow movers, so they need the biggest buffer adjustment first. Go through your top sellers from that supplier and recheck their order-by dates after you update the lead time, rather than assuming the new number is low-risk everywhere.

Step by step

1. Pull the last 5-10 purchase orders from the supplier and compare order date to actual received date
2. Calculate the average real lead time and how much it varies order to order
3. Update that supplier's lead time, or add safety days if the delay is inconsistent rather than fixed
4. Recheck order-by dates for their top-selling SKUs under the new number
5. Set a reminder to review their on-time performance again after a few more orders
6. If delays keep growing or stay severe, start qualifying a backup supplier for your top SKUs from them
7. Keep a note of what lead time you are actually using versus what they quote, so you do not slip back to trusting the quote

Worked example

Riverbend Outdoor orders from a tent pole supplier quoted at 10 days. Checking the last 6 orders, actual arrival averaged 16 days, with a worst case of 19. They update the supplier's lead time in their planning to 16 days and add 3 safety days, making it 19 total. For a SKU selling 2 units a day with 15 on hand and none on order, the new reorder point is 2 x 19 = 38 units, so they are already below reorder point and need to order now rather than waiting the old 10-day assumption.

How SteadyShelf helps

SteadyShelf lets you set the lead time and safety days per supplier, and it will recalculate order-by dates and quantities from whatever numbers you enter. It does not track on-time delivery history automatically, so you need to review past orders yourself and update the lead time when a supplier is consistently slower than quoted.

$29/month flat, unlimited products and suppliers, 30-day free trial. Run the numbers now with the free reorder point calculator.

SteadyShelf is launching on the Shopify App Store. Join early access to get the install link first.

Related guides

• How to handle backorders when you run out
• How to handle carryover stock between seasons
• How to handle damaged goods from a supplier
• How to handle a supplier price increase

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