Every Monday, we do four things for each pack. We map where its stock is, forecast its daily sales, work out how much Amazon will have each day, and decide what to send and by when. The numbers come from an example pack, not from any real brand, and the 5 sources are listed at the end.
We draw one map for each brand. It shows every place your stock sits and every route between them, with its shipping time.
Your supplier or your own productionAn order to your warehouse counts from its expected date; one straight to Amazon adds the shipping time.An order with no date stays off the daily count, but still counts as on order.
→Order75 days
Your warehouse900 on handUnits already set aside for orders don’t count.
→Transfer6 daysEach shipment covers 20 days of sales
Amazon150 for saleUnits moving between Amazon warehouses, or held for Amazon’s checks, count. Units reserved for customer orders don’t.1
→Sold10 a day
Amazon shoppersFor each channel you sell on, we note where its orders ship from. Your own site is a second channel, and it ships from your warehouse.
When a shipment on the way gets to AmazonA shipment Amazon is already checking in counts from today.A shipment that has left gets there in 6 days, the shipping time of the transfer.A shipment that hasn’t left yet gets there one full shipping time from today, plus any extra days you set.
Everything at Amazon, on the way and on order is what supply-chain courses call the inventory position: on hand, plus on order, less what is committed.2
Shipping time counts from the day a shipment leaves you to the day Amazon has it for sale, check-in included. Amazon takes 2–5 days to check in a delivered shipment.3
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2 · Forecast sales per day
We forecast each pack on each channel from the last eight weeks, and we leave out the days it was out of stock.
Units sold per day, and the forecastexample pack
10 a day: the forecast, out-of-stock days left out8.75 a day: the same sales spread over all 56 daysOut of stock
Sales per day=units sold in the last 8 weeks÷days it was in stock
490 units over 49 days in stock comes to 10 a day. Spread over all 56 days, the same sales come to only 8.75 a day, so every date we worked out from that would be too late.
A day counts as in stock when Amazon’s daily inventory ledger ends it with sellable units.4 Out-of-stock days are left out once Amazon’s records cover 30 days.
The rate stays at most 3 times the rate over all 56 days. If the pack had no stock and no sales in the 8 weeks, we look back up to 180 days for the days it did.
If a pack has no stock at Amazon on the day we run, its forecast starts from your plan, or from your site’s sales scaled to Amazon, where your site sells it. Otherwise, it keeps its last Amazon rate.
The forecast is redone every Monday.
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3 · Work out Amazon’s stock for each day ahead
We start from today’s stock, add each shipment on the day it lands, and take off a day’s sales.
Available to sell at Amazon, next 5 weeksexample pack · ▲ an arrival
Stock at Amazon if nothing is sentWith 250 units sent by Oct 13, landing Oct 19Nothing to sell without that shipment
Each day’s stock=the day before+what lands that day−sales per day
We run it day by day for 24 weeks, and it never goes below zero. In this example, that’s 150 units selling 10 a day, with nothing on the way.
The stockout date is the first day Amazon would have none left to sell: Oct 19.
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4 · Set what to send, and by when
We set three numbers for each pack: the send-by date, the target, and how many units to send.
Send by
stockout date − shipping time
Oct 19 − 6 days = Oct 13
Target
shipping time + Amazon’s safety days + the days each shipment covers
6 + 14 + 20 = 40 days = 400 units
Send
target − stock at Amazon − what’s on the way
400 − 150 − 0 = 250 units
The quantity is then raised to the route’s minimum and rounded up to full cases: 10 cases of 25. If your warehouse can’t spare the whole shipment and still serve your site, we skip it and add the units to the order list.
The send-by date is the last safe day. A shipment that leaves that day is ready to sell at Amazon on the day the pack would run out.
A pack goes on the list when its stock plus what’s on the way falls short of its target, and your warehouse can send at least the minimum. This one has 15 days of stock, and its target is 40.
We run the same count one step back, for your supplier or your production. When everything at Amazon, on the way, in your warehouse and on order covers fewer days than the order’s lead time plus safety days, the list adds an order.
That is the reorder point: forecast sales over the lead time, plus safety stock.2
What we set with you
Setting
Example
What it means
Shipping time
6 days
For each route, from the day a shipment leaves you to the day Amazon has it for sale
Days of sales each shipment covers
20 days
For each route, and it decides how often you ship
Minimum and case size
50 units · 25 a case
For each route: the smallest shipment worth sending, and your case pack
Safety days
14 days
For each place your stock sits: extra days of stock, in case a shipment is late or a week sells fast. A shipment’s target uses the safety days of the place it goes to.
We set these with you when we start, and you see each one.
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5 · The list you get
Each pack that needs a shipment or an order gets one line; the rest count in the “No action needed” tile.
Stockout PreventionYour warehouse → Amazon · run of Mon Oct 5
No action needed1
Action suggested1
Revenue at risk / mo$7,578
Product
Send
Send by
Stockout date
At Amazon now
Warehouse available
Revenue at risk / mo
Example pack A
250
Oct 13
Oct 19
150
900
$7,578
Revenue at risk per month is a week’s forecast sales times the price times 4.33, so here it’s 70 × $25 × 4.33.
Amazon’s Restock tool also suggests a ship date, from days of supply and lead time.5 Amazon can’t see your own warehouse or your open orders.
This list counts both, so it also says whether your warehouse can cover a shipment, and when to order more.
Why stockouts happen
A send-by date rests on two numbers that keep changing: how fast a pack sells, and how long a shipment takes to reach Amazon.
Amazon Seller Central