Density altitude for long-range shooting
Ballistic solvers use density altitude, or the air density behind it, to work out how much drag slows a bullet. Thinner air means less drag and a flatter path at long range. The table follows one range at 1,000 ft through a day that warms from 30 F to 100 F.
Not for flight planning. Use your aircraft's POH or flight manual and an official weather briefing.
Open these numbers in the calculator and change them to match your own conditions.
| Temperature | Density altitude |
|---|---|
| 30 F (-1 C) | -710 ft |
| 40 F (4 C) | -17 ft |
| 50 F (10 C) | 658 ft |
| 60 F (16 C) | 1,317 ft |
| 70 F (21 C) | 1,961 ft |
| 80 F (27 C) | 2,590 ft |
| 90 F (32 C) | 3,205 ft |
| 100 F (38 C) | 3,806 ft |
Shooters often read station pressure (the actual pressure where they stand) from a handheld weather meter. Set the calculator's pressure input to station pressure and enter the meter reading with the range elevation. If your meter already shows density altitude, use that figure.
How these figures are worked out
Each figure uses the National Weather Service method: station pressure from the altimeter setting and elevation, vapour pressure from the dew point, then virtual temperature and density altitude. The calculator runs the same code. Figures are rounded to the nearest foot and are estimates.