Accurate Shopify inventory planner and demand forecasting are essential for any store that works with its own warehouses. The precise forecast allows for preventing out-of-stock for trending products, reduces overstocks, and in time identifies dead inventory.
Opposite to inventory value report, inventory planner - also known as Shopify demand forecasting - asks questions for all three time periods:
- Past: How many products were sold, and how fast?
- Current: What is the actual stock status?
- Future: How many products do we need and when?
What questions can Shopify inventory forecasting answer?
Usually, each question and answer uses its own report. The overview of answers:
- how quickly the inventory is used (sales velocity)
- how to minimize chances of out-of-stock situations
- when to replenish stocks
- what inventory is dead (i.e., without sales)
- what inventory is overstocked
- what is the turnover ratio for stock
- what products require a revamp of pricing or discount policy
This list is incomplete but gives the correct look at the problem.
Key Takeaways: Shopify Inventory Planning
- Inventory Forecasting for Shopify requires history. On seasonal markets, for accurate inventory forecasting, you need at least one year of sales history. In other stable (linear) markets, the forecast can analyze the past 90 days.
- Modern reporting and inventory planning platforms allow you to manage stock as a guru.
- Many non-programmable factors may reduce accuracy. You always need to get in touch with the current market situation and adjust forecasts and plans.
Shopify inventory forecasting explained
To know how many products we need for next week or month, we should understand how fast we will sell products - it's sales velocity.
Once we know the sales velocity, we can easily calculate how many products we need for the next 14 days. But we also need to know when to place an order for the supplier - it's a reorder date or reorder point if we talk about quantity.
Also, to use inventory planner, we need to know one constant number - how many days we need to transfer the product from the supplier's stock to our stock - it's lead time.
In overview, for simplified inventory planner, we need just 3 values:
- sales velocity
- lead time
- actual quantity
Key terms and calculations
-
Sales Velocity - the number of sold items for the period (usually means velocity per day)
Simplified formula to calculate velocity based on the past 30 days:
Sales Velocity = Sold Quantity ÷ 30
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Lead Time - how many days you need to receive a product to your stock (that time includes all steps: placing an order to the supplier, signing, delivery, etc.)
-
Lead Time Quantity - how many items will be sold within the Lead Time period.
Lead Time QTY = Lead Time × Sales Velocity
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Service Level - the expected probability of not hitting a stock-out during the next replenishment cycle (or the probability of not losing sales).
Usually, the Service Level is in the range of 70-90%.
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Safety Stock - the extra quantity of inventory (buffer or reserve) to prevent out of stock if some problems occur.
Safety Stock = Sales Velocity × Lead Time × Service Level
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Reorder Point (ROP) - the stock quantity that triggers replenishment.
Reorder Point = Safety Stock + Lead Time QTY
- Stock QTY - the actual stock quantity.
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Stock Covered Time - how many days the current stock will cover sales.
Stock Covered Time = Stock QTY ÷ Sales Velocity
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Stockout QTY - if the value is positive, it is a deficit, since the product can be delivered from the supplier in time, even if the order is placed right now.
Stockout QTY = Lead Time QTY - Stock QTY
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Replenishment Quantity - how many items need to be ordered to prevent out-of-stock situations.
Replenishment QTY = Reorder Point QTY - Stock QTY
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Replenishment Time - when (how many days) products should be reordered.
Replenishment Time = Stock Covered Time - Lead Time
Examples of inventory forecasting in Shopify
Below we have collected different variations of inventory planner and demand reports that can be used with our app. Additionally, you can adjust built-in inventory planner report or create new reports.
Shopify Inventory Planner Report
It's the default report with simplified calculations and only required columns.
ProductsName | Product VariantsName | ForecastSales Velocity | Inventory LevelsTotal Available | ForecastForecast QTY 21d | ForecastReplenishment QTY 21d |
---|---|---|---|---|---|
Helios Endurance Tank | Blue / L | 0.47 | 0 | 9.80 | 10 |
Adrienne Trek Jacket | Gray / XS | 12.4 | 78 | 260.4 | 183 |
Shopify Inventory Planner Replenishment Report
ProductsName | Product VariantsName | ForecastSales Velocity | Inventory LevelsTotal Available | ForecastStock Covered Time | ForecastReplenishment | ForecastReplenishment Time |
---|---|---|---|---|---|---|
Helios Endurance Tank | Blue / L | 2 | 8 | 4 days | 30 | 0 days |
Adrienne Trek Jacket | Gray / XS | 1.5 | 80 | 54 days | 0 | 40 days |
Shopify Inventory Planner Overstock Report
ProductsName | Product VariantsName | ForecastSales Velocity | Inventory LevelsTotal Available | ForecastStock Covered Time | ForecastOverstock QTY |
---|---|---|---|---|---|
Helios Endurance Tank | Blue / L | 2 | 89 | 45 days | 75 |
Adrienne Trek Jacket | Gray / XS | 18 | 567 | 32 days | 315 |
Shopify Inventory Planner Stockout Report
ProductsName | Product VariantsName | ForecastSales Velocity | Inventory LevelsTotal Available | ForecastStock Covered Time | ForecastStockout QTY |
---|---|---|---|---|---|
Helios Endurance Tank | Blue / L | 2 | 10 | 5 days | 18 |
Adrienne Trek Jacket | Gray / XS | 18 | 67 | 4 days | 185 |
Shopify Inventory Planner Dead Stock Report
ProductsName | Product VariantsName | ForecastSales Velocity | Inventory LevelsTotal Available | Product VariantsLifetime Sales | Product VariantsFirst Sold At | Product VariantsLast Sold At |
---|---|---|---|---|---|---|
Helios Endurance Tank | Blue / L | 0 | 1420 | 19 | Oct 30, 2018 | Mar 29, 2022 |
Adrienne Trek Jacket | Gray / XS | 0 | 14 | 5 | Feb 15, 2019 | Sep 19, 2021 |
Integration with Google Sheets
Additionally, you can use our Shopify vs. Google Sheets integration to automatically export products (variants) with available stock quantity and velocity to Google Sheets. It also allows you to calculate other columns in your spreadsheet.