TL;DR
Calculate inventory turnover days as average inventory divided by COGS, multiplied by days in the period. Use opening and closing inventory at cost, COGS from the identical period, and the same locations and stock scope. A result of 60.8 days means your average inventory took about 61 days to move through during that period.
Calculate inventory turnover days as (average inventory ÷ cost of goods sold) × days in the period. For example, ₹13,50,000 of average inventory and ₹81,00,000 of COGS over 365 days equals 60.83 inventory turnover days.
A SEBI-filed calculation uses the same method: COGS divided by average beginning and ending inventory, then 365 divided by the turnover ratio.
Inventory Turnover Days Formula
Inventory turnover days show how many days your average cost-valued inventory remained on hand before sale or use.
Use either formula:
Inventory turnover days = (Average inventory ÷ COGS) × Days in period
Average inventory = (Opening inventory + Closing inventory) ÷ 2
Or calculate the ratio first:
Inventory turnover ratio = COGS ÷ Average inventory
Inventory turnover days = Days in period ÷ Inventory turnover ratio
Use the actual days in your reporting period. Use 90, 91, or 92 days for a quarter. Use 365 or 366 days for a full financial year.
Calculate Your Result with This Worksheet
Use this completed worksheet as a model. Replace the amounts and scope with your own records.
INVENTORY TURNOVER DAYS WORKSHEET
Measurement period
1 April 2025 to 31 March 2026
Days in period: 365
Scope
Business: Same legal entity as the COGS report
Locations: Warehouse A, Warehouse B, and Distribution Centre C
Stock: Company-owned raw materials, work in progress, finished goods,
and resale goods
Valuation: Cost, after the normal inventory valuation review.
Opening inventory, 1 April 2025
₹12,00,000
Closing saleable inventory, 31 March 2026
₹13,80,000
Closing slow-moving or expired inventory, reviewed carrying value
₹1,20,000
Closing inventory used
₹15,00,000
Average inventory
(₹12,00,000 + ₹15,00,000) ÷ 2
= ₹13,50,000
COGS for the same period and scope
₹81,00,000
Inventory turnover ratio
₹81,00,000 ÷ ₹13,50,000
= 6.00 times.
Inventory turnover days
365 ÷ 6.00
= 60.83 days
The result is 60.8 days. The separate ₹1,20,000 slow-moving or expired balance needs attention, even though the overall result looks reasonable.
Which Inventory and COGS Figures to Use
Use average inventory rather than ending inventory for the standard calculation. A month-end receipt, stock count adjustment, or seasonal stock build can make ending inventory unusually high or low.
A public issuer methodology defines average inventory as opening inventory plus closing inventory, divided by two. Use more frequent snapshots, such as monthly averages, when stock levels swing sharply during the year.
Use COGS, not sales revenue. COGS and inventory should both be measured at cost. Dividing selling-price revenue by cost-valued inventory makes stock appear to move faster than it does.
Match these items on both sides of the formula:
- Period: Use inventory snapshots and COGS from the same dates.
- Entity: Do not mix one subsidiary’s inventory with group COGS.
- Locations: Add every in-scope warehouse, store, and distribution centre before calculating the company total.
- Stock categories: Keep raw materials, work in progress, finished goods, and resale goods in the scope you define.
- Ownership: Include company-owned stock. Exclude customer-owned stock from your company-wide total.
- Cost basis: Use the same valuation method in inventory and COGS.
Ind AS 2 includes resale goods, finished goods, work in progress, and materials awaiting use within inventory. It also requires inventory to be measured at the lower of cost and net realisable value.
Keep damaged, expired, obsolete, or blocked inventory in the denominator at its reviewed carrying value. Do not remove it just to improve the KPI. Instead, show it as a separate aged-stock amount for action.
For multi-site operations, calculate one company total first. Then calculate the same measure by warehouse, SKU family, or product category to find the cause. Teams that need a dependable location view can use multi-location inventory visibility before exporting the calculation.
Worked Example from Warehouse Data
The worksheet uses ₹12,00,000 opening inventory and ₹15,00,000 closing inventory.
First, calculate average inventory:
(₹12,00,000 + ₹15,00,000) ÷ 2 = ₹13,50,000
Next, calculate inventory turnover:
₹81,00,000 COGS ÷ ₹13,50,000 average inventory = 6.00 times
Then calculate days:
365 days ÷ 6.00 turns = 60.83 days
A 60.83-day result means the business held its average inventory for about 61 days during the financial year.
Do not stop at the company total. In this example, ₹1,20,000 sits in slow-moving or expired stock. Break that balance down by location, product, batch, and expiry date. Lot and serial tracking helps warehouse teams trace the stock behind an aged-inventory result.
How to Calculate Inventory Turnover Ratio and Rate
Inventory turnover ratio and inventory turnover rate usually mean the same measure:
Inventory turnover ratio = COGS ÷ Average inventory
Report the result as a number of turns, such as 6.00 times per year. Do not report the ratio as a percentage.
To calculate inventory turnover from turnover days, reverse the formula:
Inventory turnover ratio = Days in period ÷ Inventory turnover days
For example:
365 ÷ 60.83 = 6.00 times
The ratio and days tell the same story in different formats. The ratio shows how often inventory moved through. Days show how long average inventory stayed on hand.
What High or Low Inventory Days Mean
Lower inventory days mean average inventory moved through faster during that period. Higher inventory days mean more cash remained tied up in stock.
Neither result works as a universal target. A distributor with frequent replenishment can run on lower days than a manufacturer carrying raw materials and work in progress.
Compare your result against the same business, product mix, season, and stock policy. Also review these operating measures beside turnover days:
- Stockouts and backorders
- Aged or expired stock value
- Fill rate
- Inventory write-downs
- Purchase lead times
- Sales forecast accuracy
A lower-days result with frequent stockouts can signal understocking. A higher-days result concentrated in one product family usually points to a purchasing, demand, or disposal decision.
Use the result to change a specific action. Reduce or pause replenishment for slow-moving items. Investigate excess stock by warehouse. Set purchasing rules from confirmed demand and lead times with forecasting and purchase automation.
Common Mistakes That Change the Result
Use this checklist before sharing the result with finance, purchasing, or warehouse teams.
Using sales revenue instead of COGS. Revenue includes margin. Use cost of goods sold.
Using a single ending balance as the standard denominator. Use opening and closing inventory to calculate average inventory.
Mixing stock values from different dates. A 31 March inventory balance needs COGS from the same reporting period.
Leaving out one location. Add all in-scope stock locations before calculating the company total.
Mixing selling-price and cost values. Inventory and COGS need the same cost basis.
Removing unusable stock from the calculation. Keep it at its reviewed carrying value, then report it separately for action.
Comparing different scopes. Do not compare a company-wide ratio with a single warehouse or SKU result.
FAQs
What If I Do Not Have an Opening Inventory Balance?
Use the earliest reliable inventory balance available and label the result as a partial-period or first-period calculation. Once you have two period-end balances, use the opening-and-closing average for the standard ratio. A new business can also calculate a monthly result after it has beginning and ending monthly stock values.
Does Inventory Turnover Include Freight and Landed Cost?
Yes, when those costs are included in your inventory valuation. Ind AS 2 says inventory cost includes purchase, conversion, and other costs that bring inventory to its present location and condition. Keep the same cost treatment in both inventory and COGS.
Can Inventory Turnover Days Be Negative?
No, not in a normal operating calculation with positive inventory and positive COGS. A negative result usually means a stock adjustment, return, data import, or valuation entry needs investigation. Resolve that record before using the result for purchasing decisions.
How Often Should Warehouse Teams Calculate Inventory Turnover Days?
Calculate it at least for each financial reporting period. Calculate it monthly when purchasing, replenishment, or aged-stock decisions happen monthly. Use the same scope each time so the trend remains useful.
At Arka, we give Salesforce teams real-time inventory visibility across warehouses and materials, including stock on hand, stock on order, lead times, and raw-material availability. Explore custom inventory reporting and Arka pricing when you need to make this calculation repeatable across locations.
