Sink Rate Calculator
Enter the altitude you lost and how long it took to get your average sink rate in m/s and ft/min, with a general read on how brisk that descent was.
Sink rate
How this calculator works
Sink rate is altitude lost divided by the time it took, giving a rate in metres per second — the same unit most variometers use. The tool also converts that figure to feet per minute, which some instruments and pilots prefer, and rounds both for readability.
The general category — gentle, moderate, strong, or very strong — is a rough orientation based on widely-used rules of thumb, not a fixed technical standard. Use it to sanity-check a reading, not as a precise classification of what the air (or your flying) was doing.
Frequently Asked Questions
What's the difference between sink rate and glide ratio?
Sink rate is purely vertical — how fast you're losing height, regardless of how far forward you're travelling. Glide ratio brings forward distance into the picture. A glider can have a very good glide ratio while still sinking at a meaningful rate; the two numbers describe different things and are both useful.
How do I measure altitude lost and time in the field?
A vario or GPS flight logger records both directly, and most instruments can show you the altitude change over a chosen interval. Without one, a rough approximation is possible from an altimeter reading and a watch, though a logger will always be more precise, especially over shorter intervals.
Why does the sink rate change during a flight?
Sink rate depends on airspeed, wing loading, and what the air itself is doing. Flying faster (more bar) generally increases sink rate; flying in rising air can offset or reverse it; and manoeuvres like big ears or a spiral intentionally increase sink rate to lose height quickly. This tool measures whatever the air and your flying combined to produce over the interval you enter — it doesn't separate the two.
What counts as a 'strong' sink rate?
The bands this tool shows are general and approximate: a typical paraglider's best-glide sink rate at trim speed is often in the gentle-to-moderate range, while intentional descent techniques like big ears, B-line stalls, or spiral dives can push sink rate much higher. Treat the labels as orientation, not a technical classification.
General guidance only, not a substitute for certified instruction on descent techniques. Manoeuvres that deliberately increase sink rate (big ears, B-line stalls, spirals) carry real risk and should only be learned and practised under a certified instructor, ideally over water with a safety boat during a proper SIV course.