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Days to Cover
Days to cover is the number of average trading days it would take short sellers to buy back every shorted share. You get it by dividing short interest by average daily volume. It measures how crowded the exit is, not whether anyone is trapped.
What days to cover tells you
Days to cover answers one narrow question: if every short seller decided to buy back at once, and they could only use an ordinary day's trading volume to do it, how many days would that take? A reading of 1 means the whole short position could be closed in about one normal session. A reading of 8 means the shorts would need more than a week and a half of the stock's usual volume, and that's assuming nobody else wants to buy.
That's why squeeze watchers like it. A high number says the exit is narrow. It doesn't say the shorts are losing, that they're under pressure, or that they want out. Plenty of high days-to-cover names sit there for months and do nothing.
The formula
Days to cover = short interest / average daily volume
Short interest is the number of shares sold short and not yet bought back. Average daily volume is usually a 20-day or 30-day average, and data providers don't all use the same window, so two sites can print different numbers for the same stock on the same day. Check which window you're reading before you compare.
Worked example
Example numbers only. These are not real stocks.
| Example stock | Short interest (shares) | Avg daily volume (shares) | Days to cover |
|---|---|---|---|
| A | 4,000,000 | 2,000,000 | 2.0 |
| B | 4,000,000 | 500,000 | 8.0 |
| C | 12,000,000 | 1,500,000 | 8.0 |
| D | 1,200,000 | 6,000,000 | 0.2 |
A and B have the same short interest. B reads four times higher only because it trades less. C and B print the same 8.0 with very different share counts. The ratio hides the size, so read it next to the raw numbers, not instead of them.
Why the data lags
In the US, brokers report short positions to FINRA twice a month, and the figures are published several business days after the settlement date they describe. By the time you see a short interest number, it can be two or three weeks old. The volume side of the ratio is fresh. The short side isn't. That mismatch is where most bad days-to-cover reads come from.
It fails in a predictable way. A stock runs hard, volume explodes, and days to cover collapses because the denominator jumped, even if not one short covered. Or the shorts quietly cover during a slow week and the old report still shows them sitting there. Daily estimates from data vendors try to close the gap, but they're estimates built from lending data, not the official count.
Days to cover vs short % of float
Short % of float divides short interest by the shares available to trade. It tells you how much of the tradable stock is borrowed and sold. Days to cover tells you how long the exit takes at normal volume. They answer different questions.
Example: 4,000,000 shares short in a 20,000,000-share float is 20% of float. The same 4,000,000 shares short in a 200,000,000-share float is 2%. Days to cover could be identical for both if the volume lines up. A small float with a high short percentage and thin volume is the combination people mean when they say "crowded." Even then, the borrow has to stay tight and the price has to move for anything to happen. A ratio is not a squeeze. Our float guide covers how float gets counted and why it changes after offerings and reverse splits.
FAQ
What is a high days to cover?
There's no official line. Many traders start paying attention above roughly 5, but a 5 in a stock that trades 300,000 shares a day is a very different animal from a 5 in one that trades 30 million. Look at the share counts and the borrow too.
How do I calculate days to cover?
Take the latest short interest and divide it by average daily volume. Use the same volume window every time, and note the settlement date on the short interest figure so you know how old it is.
Does a high days to cover mean a short squeeze is coming?
No. It means covering would take a while at normal volume. A squeeze also needs the price to move against the shorts and the borrow to get expensive or scarce. Most high readings never turn into one. Our lesson on being cautious with squeeze setups walks through how these go wrong.
Why did days to cover drop when the stock spiked?
Because volume rose. The short interest figure is from the last report, so a big volume day shrinks the ratio on paper even if no shorts covered.
For the short interest side of the math, see short interest, and for the full set of squeeze numbers in one place, our squeeze metrics reference. For how these setups actually unwind, read short squeeze.
This page is education, not financial advice.