Ecommerce
Stocking a target number of days of cost of goods tells you the cash the shelves will absorb.
Cost of goods and target cover
Cost of goods sold per month, in your local currency.
How many days of stock you want to hold on hand.
Safety stock value
Extra buffer stock held against demand spikes or supply delays.
Inventory Investment Needed
53,000
Daily COGS times target days, plus safety stock.
Formula verified 13 September 2026
Daily COGS
800.00
Monthly COGS divided by 30.
Days of Inventory
66
How many days of cover the investment buys, including safety stock.
Estimate only — platform fees and costs vary; verify current rates. Read the full disclaimer ↓
How much cash sits in stock as you change the target days of inventory, with your safety-stock buffer added throughout. More days of cover means more working capital frozen on the shelf.
| Target days | Base inventory | Plus safety stock | Total investment |
|---|---|---|---|
| 30 | 24,000.00 | 5,000.00 | 29,000.00 |
| 45 | 36,000.00 | 5,000.00 | 41,000.00 |
| 60 ◀ | 48,000.00 | 5,000.00 | 53,000.00 |
| 90 | 72,000.00 | 5,000.00 | 77,000.00 |
Estimates only — not financial, tax, or professional advice.
100% private — every number you enter is calculated in your browser and never sent to our servers.
What it calculates: Inventory Investment Needed, Daily COGS, Days of Inventory.
Updated 5 June 2026 · Transparent assumptions
Choosing to hold 60 days of stock rather than 30 is not a warehousing preference, it is a decision to tie up an extra month of cost of goods in stock indefinitely. This converts the cover target into that figure.
For a growing business it is the number that explains why profit and cash diverge. Growth requires more stock, so a profitable month can still consume cash — and the faster the growth, the wider that gap.
The input is cost of goods sold, because that is what the stock cost you. Using revenue instead overstates the investment by the whole gross margin, which on a typical ecommerce business is a factor of two or three.
It is a common error precisely because sales figures are the ones people have to hand. The number needed here is the cost side, from the same period.
A sensible cover target starts from supplier lead time and adds safety stock and a review cycle. A 30-day lead time with a fortnight of buffer implies around 45 days, and a target of 90 needs a reason beyond it sounding safe.
Every extra day of cover is working capital the business cannot use elsewhere, priced at the carrying cost rate. Rounding the target up because it feels comfortable is a real cost with no offsetting benefit.
Once you know the investment, the next question is where the cash comes from: supplier credit, a facility, or retained profit. Supplier payment terms are the cheapest lever — 60-day terms on a 45-day cover means the stock is sold before the invoice is due.
Where terms are short and cover is long, the business funds the gap itself. That gap, not the profit margin, is usually what limits how fast a physical-product business can grow.
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Business disclaimer
Results are estimates for planning and analysis based on the figures you enter. They are not accounting, tax, or financial advice — verify with your own records and a qualified professional before making decisions.
How we calculate · Found an error? email us
Published 13 September 2026