Inventory Stock Calculator
Get your stock numbers fast. This free tool finds your reorder point, safety stock, EOQ, carrying costs, and turnover ratio. It's made for inventory managers. It's made for warehouse teams too. Small business owners use it as well.
Get your inventory numbers in 3 simple steps
Select Your Calculator
Pick one of 6 calculators below. Each one solves a different stock problem.
Enter Your Numbers
Type in your daily sales. Add your lead times or cost figures. Every field has a tooltip to help.
Get Instant Results
See your results right away. Each result comes with a plain note. It tells you what to do next.
Reorder Point Calculator
Find the exact stock level at which you should place a new order — so you never run out.
Formula Used
Safety Stock Calculator
Calculate the buffer inventory needed to protect against unexpected demand spikes or supply delays.
Formula Used
Economic Order Quantity (EOQ) Calculator
Find the optimal order quantity that minimises total ordering and holding costs.
Formula Used
Inventory Carrying Cost Calculator
Understand the true annual cost of holding your inventory, including storage, insurance, and depreciation.
Inventory Turnover Ratio Calculator
Measure how many times your inventory is sold and replaced in a year — a key indicator of business efficiency.
Formula Used
Days Inventory On Hand (DOH) Calculator
Find out how many days your current stock will last at your current sales rate.
Formula Used
How inventory decisions connect
Every number you calculate feeds into the next decision. This is how professional inventory management works.
Why Inventory Calculations Matter
Poor inventory habits cost businesses a lot. The global cost is near $1.1 trillion a year. This comes from overstocking and running out of stock. Learning these formulas helps you avoid that.
What is a Reorder Point?
A reorder point tells you when to order more stock. It uses your average daily sales. It multiplies that by your lead time. Then it adds a safety buffer. This way, you don't run out while waiting on a delivery.
What is Safety Stock?
Safety stock is extra stock you keep on hand. It's your buffer against demand spikes. It also protects you from late suppliers. You find it by comparing your max and average demand. Too little safety stock causes stockouts. Too much ties up your cash.
What is EOQ?
EOQ stands for Economic Order Quantity. It's the best number of units to order each time. It balances two costs. One is the cost of ordering too often. The other is the cost of holding too much stock. The formula finds the middle ground.
What is Inventory Turnover?
Inventory turnover shows how fast you sell and replace stock. It's measured over a year. A high ratio means your business runs well. A low ratio means cash sits in slow stock. Most healthy retail stores aim for 6 to 10 times a year.
What are Carrying Costs?
Carrying costs are what it costs to hold your stock. This covers storage. It covers insurance. It also covers depreciation. On average, this runs 20% to 30% of your stock value each year. Knowing this number helps you plan ahead.
What is Days on Hand (DOH)?
Days on Hand shows how long your stock will last. You divide your stock units by your daily sales. This helps you time your next order. It also helps you spot slow stock early.
Ready to automate these calculations?
These calculators give you the numbers by hand. InventorysHub tracks all of them for you. It does this in real time, across your whole business.