About the Short Interest & Days to Cover Calculator
Short interest is the number of a company’s shares that have been sold short and not yet bought back. On its own the figure means little, so traders scale it two ways: as a percentage of the float (shares available to trade) and as days to cover — the short interest divided by average daily volume, which estimates how many days of normal trading it would take for every short seller to buy back. This short interest calculator computes both, plus the dollar value of the short position and its annual borrowing cost.
It is useful for traders screening for crowded shorts and potential short squeezes, long investors gauging how bearish the market is on a holding, and students learning market-structure metrics. Enter the previous report’s figure as well to see whether shorts are building or covering.
In the US, FINRA requires broker-dealers to report short positions twice a month and publishes the totals roughly a week and a half after each settlement date, so the data is always somewhat stale. Float and volume definitions differ between data providers, which is why published short-float percentages vary.
With the default inputs, the days to cover (short interest ratio) is 4.8 days. Change any value above to recalculate instantly.
How to use the short interest & days to cover calculator
- 1Enter the latest reported short interest in shares.
- 2Enter the float and shares outstanding from the company profile.
- 3Enter the average daily trading volume (30-day average is common).
- 4Add the share price, borrow fee and previous short interest if you have them.
- 5Read days to cover and short % of float to judge how crowded the short is.
Formula and method
Days to cover, also called the short interest ratio, divides the total number of shares sold short by the average number of shares traded per day. It estimates how many days of normal volume short sellers would need to buy back all their shares, assuming they could use the entire daily volume. Higher numbers mean a short squeeze could be more violent if buying pressure appears.
Short interest as a percentage of float compares the short position with the shares actually available to trade (shares outstanding minus insider and restricted holdings); as a percentage of shares outstanding it uses every issued share and so is always lower. The dollar value is short interest × price, and the annual borrow cost applies the stock loan fee to that value.
- Short interest
- Shares sold short and not yet covered
- Average daily volume
- Average shares traded per day over a recent period
- Float
- Shares available for public trading
Worked examples
Mid-cap with 12 million shares short
12 million shares short ÷ 2.5 million traded a day = 4.8 days to cover. That is 15% of the 80 million share float (12% of shares outstanding), worth $300 million at $25. Short interest is up 20% from 10 million at the previous report.
Heavily shorted squeeze candidate
Shorts hold 40% of the float and would need 10 full days of volume to cover. With a 25% borrow fee they pay about $90 million a year to stay short, which adds pressure to cover if the price rises.
Large-cap with light short interest
Only 0.375% of the float is short and it would take less than a fifth of a day’s volume to cover. Short interest fell 25% since the last report as shorts bought back shares.
Frequently asked questions
What is a high days-to-cover ratio?+
Many traders treat days to cover above about 5 as elevated and above 10 as crowded. It depends on the stock: thinly traded small caps can show high ratios simply because volume is low.
What percentage of short interest is considered high?+
Short interest above roughly 10% of float is generally viewed as high and above 20% as very high. Most large, liquid stocks have short interest in the low single digits.
How often is short interest reported?+
In the US, FINRA rules require broker-dealers to report short positions twice a month, as of mid-month and month-end settlement dates. FINRA and the exchanges publish the totals several business days later.
What is a short squeeze?+
A short squeeze happens when a heavily shorted stock rises and short sellers rush to buy shares to limit losses. Their buying pushes the price higher still. High short interest and high days to cover make a squeeze more likely, but do not guarantee one.
Why do different websites show different short float numbers?+
Providers use different float definitions (some exclude more insider or institutional holdings), different average-volume windows, and different report dates, so the same short interest can produce noticeably different percentages.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.