How to Calculate Average Rate of Sale

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Average Rate of Sale (ROS) Calculator

Set to 1 if you are calculating for a single store or website.

Results

function calculateROS() { var units = parseFloat(document.getElementById('unitsSold').value); var days = parseFloat(document.getElementById('timePeriod').value); var stores = parseFloat(document.getElementById('storeCount').value); var resultDiv = document.getElementById('rosResult'); var mainDisplay = document.getElementById('mainResult'); var secondaryDisplay = document.getElementById('secondaryResult'); if (isNaN(units) || isNaN(days) || isNaN(stores) || days <= 0 || stores <= 0) { alert("Please enter valid positive numbers for all fields."); return; } // ROS Formula: Total Units / (Number of Days * Number of Stores) var ros = units / (days * stores); var weeklyRos = ros * 7; resultDiv.style.display = 'block'; mainDisplay.innerHTML = ros.toFixed(2) + " Units Per Store/Day"; secondaryDisplay.innerHTML = "This equates to approximately " + weeklyRos.toFixed(2) + " units per store per week."; }

Understanding the Rate of Sale (ROS)

The Rate of Sale (ROS), also commonly referred to as the "sales velocity," is a vital retail metric that measures how many units of a specific product are sold within a given period across active selling locations. Unlike simple sales totals, ROS allows inventory managers and buyers to compare product performance regardless of how many stores carry the item or how long it has been on the shelf.

The Average Rate of Sale Formula

To calculate the Average Rate of Sale, you divide the total units sold by the length of time they were available, then divide that by the number of locations selling the product.

ROS = Total Units Sold / (Number of Days × Number of Stores)

Why This Metric Matters

  • Inventory Planning: ROS tells you how quickly you will run out of stock. If your ROS is 5 units/day and you have 50 units in stock, you know you have exactly 10 days of cover.
  • Fair Comparison: A product sold in 100 stores will always have higher total sales than a product in 10 stores. ROS "levels the playing field" so you can see which product is actually more popular with customers.
  • Benchmarking: You can compare the ROS of a new product against the historical average of its category to determine if it is a "winner" or a "slow mover."

Example Calculation

Imagine you own a boutique chain with 5 locations. You sold 1,050 units of a specific denim jacket over the last 30 days. To find your ROS:

  1. Total Units: 1,050
  2. Total Days × Stores: 30 days × 5 stores = 150 "selling days"
  3. Calculation: 1,050 / 150 = 7.0 units per store per day.

If your weekly target for this category is 5.0 ROS, your denim jacket is significantly over-performing, and you should consider increasing your next purchase order.

How to Improve Your Rate of Sale

If a product has a low ROS, retailers typically look at three levers:

  1. Price: Reducing the price (markdowns) usually increases the velocity of sales.
  2. Promotion: Improving the product's placement in-store or increasing marketing spend can drive higher ROS.
  3. Distribution: Sometimes a product has a low ROS because it is in the wrong stores. Moving stock from low-performing locations to high-performing ones can optimize the overall chain ROS.

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