Days to cover

Days to cover divides the shares sold short by the stock's average daily volume. It answers a rough question: if every short seller tried to buy back at once, how many days of ordinary trading would that take? A high figure means the short side is crowded relative to how much the stock trades, which is one ingredient of a squeeze. It says nothing about timing.

Short interest is reported by FINRA twice a month with a lag, so the number you see is already old. Providers also calculate float differently, so the percentage of float can disagree from one data source to the next. The short interest and float pages explain both measures.

Borrow cost

A hard-to-borrow stock carries a fee quoted as an annual rate, charged daily on the value of the shares you have borrowed, and the rate can change from one day to the next. Brokers differ on the day-count basis and on how they value the position for the fee, so check the details in your account. The fee keeps running for as long as the short stays open.

More on the locate requirement, recalls and fees is in hard to borrow, and the wider case for treating shorting as its own discipline is in short selling is a separate skill.