Shopify Demand Planning & Inventory Forecasting Reports

Lower the chances of out-of-stock situations and prevent stock overflow.

Accurate inventory forecasting and demand planning are essential for any store that work with its own warehouses. The precise forecast allows for preventing out-of-stock for trending products, reduces overstocks, and in time identity dead inventory.

Opposite to inventory value report, inventory forecasting - also known as demand planning - asks questions for all three time periods:

  • Past: How many products were sold and how fast?
  • Current: What is the actual stock status?
  • Feature: How many products do we need and when?

What questions the inventory forecasting can answer

Usually, each question and answer used its own report. The overview of answers:

  • how quickly the inventory is used (sales velocity)
  • how to minimize chances of out-of-stock situation
  • when to replenish stocks
  • what inventory is dead (i.e. without sales)
  • what inventory is overstock
  • what is the turnover ratio for stock
  • what products require to revamp pricing or discount policy

This list is incomplete but gives the correct look at the problem.

Key takeaways

  • Forecasting requires history. On seasonal markets, for accurate forecasting, you need as 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.

Explanations on inventory forecasting

To know how many products we need for next week or month, we should understand how fast products we will sell - it's a sales velocity.

Once we know sales velocity we can easily calculate how many products we need for the next 14 days. But also we 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 forecast, we need to know one constant number - how many days we need to transfer product from supplier stock to our stock - it's a lead time.

In overview, to simplified forecasting we need just 3 values:

  1. sales velocity
  2. lead time
  3. 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
  • 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
  • Service Level - is the expected probability of not hitting a stock-out during the next replenishment cycle (or probability of not losing sales).

    Usually, the Service Level is in the range of 70-90%.

  • Safety Stock - extra quantity of inventory (buffer or reserve) to prevent out of stock if some problems happened.

    Safety Stock = Sales Velocity × Lead Time × Service Level
  • Reorder Point (ROP) - the stock quantity that triggers replenishment.

    Reorder Point = Safety Stock + Lead Time QTY
  • Stock QTY - actual stock quantity.
  • Stock Covered Time - how many days current stock will cover sales.

    Stock Covered Time = Stock QTY ÷ Sales Velocity
  • Stockout QTY - - if the value is positive, is a deficit, since the product can be delivered from the supplier in time, even placing the order right now.

    Stockout QTY = Lead Time QTY - Stock QTY
  • Replenishment Quantity - how many items need to order to prevent out-of-stock.

    Replenishment QTY = Reorder Point QTY - Stock QTY
  • Replenishment Time - when (how many days) products should be reordered.

    Replenishment Time = Stock Covered Time - Lead Time

Examples of inventory planning reports for Shopify

Below we collected different variations of inventory forecast and demand reports that can be with our app. Additionally you can adjust built-in inventory reports or create new reports

Shopify Inventory Planning 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 Replenishment Report

ProductsName Product VariantsName ForecastSales Velocity Inventory LevelsTotal Available ForecastStock Covered Time ForecastReplenishment ForecastReplenishment Time
### ### 2 8 4 days 30 0 days
### ### 1.5 80 54 days 0 40 days

Shopify Inventory Overstock Report

ProductsName Product VariantsName ForecastSales Velocity Inventory LevelsTotal Available ForecastStock Covered Time ForecastOverstock QTY
### ### 2 89 45 days 75
### ### 18 567 32 days 315

Shopify Inventory Stockout Report

ProductsName Product VariantsName ForecastSales Velocity Inventory LevelsTotal Available ForecastStock Covered Time ForecastStockout QTY
### ### 2 10 5 days 18
### ### 18 67 4 days 185

Shopify Dead Stock Report

ProductsName Product VariantsName ForecastSales Velocity Inventory LevelsTotal Available Product VariantsLifetime Sales Product VariantsFirst Sold At Product VariantsLast Sold At
### ### 0 1420 19 Oct 30, 2018 Mar 29, 2022
### ### 0 14 5 Feb 15, 2019 Sep 19, 2021

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