What is float rotation?
Float rotation compares the volume a stock has traded with its float, the shares that are free to trade. It answers one question: how many times over has the whole tradable supply changed hands today?
The formula is a single division:
Float rotation = volume traded so far ÷ float
Take stock A, a small cap with a float of 4.5 million shares. By mid-morning it has traded 12.6 million shares. 12.6 ÷ 4.5 = 2.8, so its float has rotated 2.8 times.
That doesn't mean every share moved 2.8 times. Long-term holders may not have sold a single share, while day traders passed the same shares back and forth dozens of times. Rotation is a measure of how busy a stock is compared with its supply, not a count of who traded.
The calculator at the top of this page does the division for you, and says how many more shares the next full rotation takes.
How to calculate float rotation
You need two numbers, both in shares:
- The float. It comes from company filings through data providers. Different sources can show different floats for the same stock, and a recent offering may not show yet, so the guide to low float stocks is worth reading on where the number comes from.
- The volume so far. The shares traded in the session up to now. Decide whether you count the premarket, and count it the same way every time.
Then divide the volume by the float. Here is stock A through one morning, its float 4.5 million shares and the premarket counted:
| Time (ET) | Volume so far | Float rotation |
|---|---|---|
| 07:00 | 0.9 million | 0.2 |
| 09:30 | 4.5 million | 1.0 |
| 10:00 | 9.0 million | 2.0 |
| 11:00 | 12.6 million | 2.8 |
The first full rotation came at the open. The second took only thirty minutes more: the stock was trading its whole float every half hour.
How traders read float rotation
Rotation and relative volume often show up together, but they measure different things. RVOL compares today's volume with what the stock usually trades by the same time of day; the guide to relative volume covers how it works. Rotation compares today's volume with the supply of shares. A stock with a large float can have a high RVOL and still be far from one rotation. A low float stock with a high RVOL can rotate its float before the open.
Small-cap traders tend to note a few moments, as habits of the trade rather than rules:
- The first rotation. The moment the day's volume equals the float. Many traders mark the time and the price, and watch whether buyers keep coming after it.
- Each new rotation. A stock that keeps climbing as it trades its float again and again has a steady stream of new buyers. One that trades its float again and again while the price stalls or slips has shares changing hands without progress, which many traders read as sellers meeting every bid.
- The speed of each rotation. A float that took two hours to rotate once and then rotates in twenty minutes is a stock whose attention is growing fast.
None of these is a signal on its own. What a rotation means depends on the catalyst, on where the price is against the day's levels, and on whether new shares are coming to market.
Float rotation in the premarket
Low float stocks with news can trade a large share of their float before the regular session opens, sometimes more than all of it. The premarket runs from 04:00 to 09:30 ET; the guide to premarket hours shows when that falls on your own clock.
Traderly's scanner counts a stock's volume from 04:00 ET and shows its float, so the two numbers the calculator needs are side by side on the list. Its market data is delayed 15 minutes, so the rotation you work out from it is the stock's rotation as it was 15 minutes earlier: useful for building your list and for reviewing sessions, not for timing an entry as it happens.
The limits of float rotation
Rotation is a ratio, and a ratio is only as good as the two numbers behind it.
- The float can be wrong. Providers update it with a delay. A company that has just sold millions of new shares has a larger float than the one on your screen, so its real rotation is lower than the number you calculate.
- New shares change the picture during the day. An offering priced in the morning adds supply right away. A stock that seemed to rotate its float three times may have done so on a float that had already grown.
- Large floats rarely rotate. On a stock with hundreds of millions of shares in its float, rotation stays a small fraction all day and tells you little. It is a number for small caps.
- It doesn't say which way. A rotation of 5 happens on the day's best runners and on its worst collapses.
Practicing with float rotation
Rotation is easier to understand on many sessions than on one. Pick a few low float stocks that moved, and replay their sessions: note the time each one reached its first, second and third rotation, and what the price did around each. After a few weeks, the numbers stop being abstract.
The guide to practicing day trading lays out a routine for that kind of review, session after session, without money at risk.