Short Interest Ratio Calculator
Calculate the short interest ratio (days to cover) from shares sold short and average daily volume.
A high ratio signals elevated short squeeze risk.
Short Interest Ratio (Days to Cover)
The short interest ratio — also called days to cover — measures how many days it would take short sellers to buy back all their borrowed shares, given normal trading volume.
Formula:
Short Interest Ratio = Shares Sold Short / Average Daily Volume
| Input | Meaning |
|---|---|
| Shares sold short | The total number of shares currently borrowed and sold by bears |
| Average daily volume | The average number of shares traded per day (typically 10 or 30-day average) |
Short interest as a percentage of float:
Short % of Float = Shares Sold Short / Float Shares
This tells you what fraction of the available shares are being bet against. A short % of float above 20% is considered very high.
Interpreting days to cover:
| Days to Cover | Interpretation |
|---|---|
| Under 1 day | Very low — bears can exit quickly |
| 1 – 3 days | Low — minimal squeeze risk |
| 3 – 5 days | Moderate — watch for catalysts |
| 5 – 10 days | High — meaningful squeeze potential |
| Over 10 days | Very high — significant squeeze risk if stock moves up |
Why it matters:
When a heavily shorted stock rises, short sellers face mounting losses and must eventually buy shares to close their positions. This buying pressure can accelerate the stock’s rise in a feedback loop — a short squeeze. The days-to-cover ratio tells you how quickly that covering wave could arrive.
Important data note:
In the US, the SEC requires short interest reporting twice per month. The data you see is typically 7 – 14 days old by publication time. For highly volatile situations, the picture can change faster than the data updates.
Limitations:
High short interest is not automatically bullish — sometimes the bears are right. Many large short positions are hedges (e.g., from convertible bond arbitrage) rather than directional bets. Always combine short interest data with fundamental analysis before drawing conclusions.