Days Inventory on Hand Calculator: See How Long Your Stock Will Last
"How long will this last?" is one of the most useful questions in any business that sells products. This free days inventory on hand calculator answers it in seconds. Enter what you have and how fast it sells, and you'll see how many days and weeks your stock will last, plus the date you're likely to run out.
Prefer to look at the whole business? Switch to the value view. Enter your stock value and your yearly cost of goods sold, and you'll see how many days of sales your stock covers.
Work out your days on hand
Two ways to use the days inventory on hand calculator
By units works best for a single product. It's the quickest way to answer "Do I need to order this week?" Divide the units you have by the units you sell each day, and you get the number of days until the shelf is empty. The tool also counts forward from today to show the likely run-out date, so you can compare it with your supplier's delivery time.
Use this view of the days inventory on hand calculator on your best sellers every week. It's also handy before a holiday, a sale, or a supplier shutdown, when you need to know whether today's stock will carry you through.
Units view
Days on hand = units in stock ÷ units sold per day
Value view
Days on hand = stock value ÷ yearly cost of goods sold × 365
By value looks at the whole business at once. It uses money instead of units, so you can mix hundreds of products into one number. This is the view accountants, lenders, and investors tend to use. It tells you how many days of sales are sitting on your shelves right now.
Use this view of the inventory days calculator once a month, and watch the trend. If the number keeps climbing, you're buying faster than you sell. If it keeps falling, you may be heading for empty shelves.
A worked example
A party supply shop has 1,500 packs of paper cups in its stockroom. It sells about 50 packs a day. The days inventory on hand calculator shows 30 days of stock, or just over 4 weeks. Each pack cost $12, so the shop has $18,000 of cups on hand.
The supplier takes 10 days to deliver. With 30 days of stock, the owner has time, but not much. They plan the next order for about 2 weeks from now, so the new cups land with a few days to spare. Then they switch to the value view. The shop holds $120,000 of stock in total and had $720,000 of cost of goods sold last year. That's about 61 days of stock across the business, which tells the owner that some other products are moving far more slowly than the cups.
What your number means
- Under 7 days Order now. One busy day or late delivery could empty the shelf.
- 7 to 14 days Tight. Check delivery times and get an order moving soon.
- 15 to 90 days A healthy range for most products and businesses.
- Over 90 days Likely too much. Cash and space are tied up in slow stock.
Why days on hand beats a plain stock count
A count of 500 units sounds like a lot. But if you sell 100 a day, it's gone by Friday. If you sell 2 a day, it will last most of a year. The raw count can't tell you which, and that's why it so often leads to the wrong decision.
Days on hand puts every product on the same scale. A fast seller and a slow seller can sit side by side in one report, and you can see at a glance which needs an order and which needs a sale. It also makes conversations easier. "We have 9 days of cups left" is clearer to a team, a supplier, or a business partner than "we have 450 packs". Using a days inventory on hand calculator turns a number on a shelf into a deadline you can plan around.
The same is true for the business as a whole. An inventory days calculator in value mode shows how many days of sales your money is sitting in. When that number drops, cash is coming back to you faster. When it rises, more of your cash is waiting on shelves.
Tips for a more useful result
Use recent sales. Average your daily sales over the last 30 to 90 days. Older data can hide a recent rise or fall in demand.
Leave out stock you can't sell. Damaged, expired, or reserved units shouldn't count. Including them makes your days on hand look better than they are.
Compare with delivery time. Days on hand only matters next to how long a new order takes to arrive. Twenty days of stock is plenty with a 3-day supplier, but a problem with a 30-day one.
Plan for seasons. A product that sells 50 a day in spring might sell 120 a day in December. Run the DOH calculator with your expected busy-season sales before the rush starts.
Check your slowest products too. Very high days on hand is just as important as very low. It points to stock you could clear, discount, or stop reordering.
Make it a habit. A weekly check on key items and a monthly check on the whole business is enough for most owners.
Know how long every product will last, every day
A days inventory on hand calculator gives you one answer at a time. InventorysHub tracks stock and sales for every product in real time and warns you when items run low, so you never have to work it out by hand again.
Frequently asked questions
What does a days inventory on hand calculator show?
It shows how many days your current stock will last at your normal rate of sales. In the units view it also gives weeks of stock and a likely run-out date.
What is a DOH calculator?
DOH is short for days on hand. A DOH calculator is the same tool under a shorter name. It turns your stock and sales into a number of days.
Should I use units or value?
Use units for single products and day-to-day buying. Use value for the whole business, monthly reports, or when talking to a lender.
Is an inventory days calculator the same thing?
Yes. "Inventory days" and "days on hand" describe the same number: how many days of sales your stock can cover.
How many days of stock should I keep?
Enough to cover your supplier's delivery time plus a small cushion for busy days. For most products, that lands somewhere between 15 and 90 days.
Can InventorysHub track this for me?
Yes. InventorysHub keeps live stock counts and sales history for every product, and it alerts you when stock runs low, so you always know what's running short.
More free stock tools
Interested in the finance side of this number? Read our guide for accountants and owners.