Density Altitude Calculator
Calculate density altitude instantly from field elevation, temperature, and altimeter setting. Essential for safe flight planning in hot, high, and humid conditions.
Common Scenarios
Click any scenario to load it into the calculator.
| Location | Elev | Temp | ~DA |
|---|---|---|---|
| Denver, CO (KDEN) | 5,430 ft | 95°F | 9,121 ft |
| Phoenix, AZ (KPHX) | 1,135 ft | 115°F | 5,262 ft |
| Sea Level, Standard Day | 0 ft | 59°F | 0 ft |
| Leadville, CO (KLXV) | 9,934 ft | 75°F | 13,362 ft |
| Dallas, TX (KDAL) — Humid | 487 ft | 100°F | 3,852 ft |
What is Density Altitude?
Density altitude is the altitude at which the air density matches standard atmospheric conditions (ISA). It is the single most important performance indicator for any piston or turbine aircraft, because your engine and wings perform as if they were at that altitude — regardless of your actual elevation.
On a hot summer day at Denver International Airport (5,430 ft elevation), the air can behave as if the aircraft is at 8,000 to 9,000 ft. That means longer takeoff rolls, reduced climb rates, and decreased engine power output.
How is Density Altitude Calculated?
Step 1: Pressure Altitude
PA = Field Elevation + (29.92 - Altimeter Setting) x 1,000
Step 2: ISA Standard Temperature
ISA Temp = 15°C - (PA x 0.00198)
Step 3: Density Altitude
DA = PA + 120 x (OAT - ISA Temp)
Why Does Density Altitude Matter?
- Takeoff distance: Higher density altitude = longer runway needed. A Cessna 172 at sea level needs ~1,600 ft; at 8,000 ft density altitude, it needs ~3,000 ft.
- Climb rate: Rate of climb can drop 50% or more at high density altitudes. If terrain rises faster than you can climb, you are in danger.
- Engine performance: Normally aspirated engines lose approximately 3% power per 1,000 ft of density altitude.
- True airspeed vs. indicated: At high density altitudes, your true airspeed is higher than indicated, which means faster ground speeds on landing (and longer stopping distances).
The Three H's: Hot, High, and Humid
Pilots memorize the "three H's" as the recipe for dangerously high density altitude:
Hot
High OAT reduces air density
High
Higher elevation = less dense air
Humid
Water vapor displaces oxygen molecules
Density altitude is tested on every FAA written exam. Are you ready?
Try this sample question from the FAA Private Pilot Knowledge Test:
An airport at 6,000 ft elevation has an outside air temperature of 35°C and an altimeter setting of 29.80 inHg. What is the approximate density altitude?
Thousands of practice questions with detailed explanations, performance tracking, and smart review.
Start your exam prep — $7.49/mo (50% off)This free density altitude calculator is designed for pilots, student pilots, flight instructors, and anyone planning flights in challenging conditions. It uses the standard ISA atmosphere model with optional humidity correction via dew point for the most accurate results outside of a full weather station. Always cross-reference with official POH performance charts and current METAR/TAF data before flight.