🌡️ Density Altitude Calculator
Enter your pressure altitude and the outside air temperature to estimate density altitude and the ISA standard temperature — and see how much performance the day is costing you.
⛰️ How Thin Is the Air?
What is a Density Altitude Calculator?
It converts pressure altitude and temperature into density altitude — the effective altitude your aircraft feels. It first works out the ISA standard temperature for your altitude, then adds density altitude for every degree the air is warmer than standard, so you can see at a glance how hot-and-high the day is.
Use it to see how heat and elevation push density altitude up. It is a rule-of-thumb estimate that rounds up, not a performance figure: takeoff distance, climb and payload come from the aircraft's POH/AFM performance charts.
❓ Frequently Asked Questions
What is density altitude?
Density altitude is pressure altitude corrected for temperature — the altitude at which the air density matches what you're actually experiencing. On a hot day the air is thinner than standard, so the aircraft performs as if it were flying much higher. It's the single number that best predicts takeoff distance, climb rate, and true airspeed on a given day.
How does this calculator estimate it?
It finds the ISA standard temperature for your pressure altitude — 15 °C at sea level, decreasing about 2 °C per 1000 feet — then adds roughly 120 feet of density altitude for every degree Celsius the actual temperature is above standard (and subtracts when colder). It's a well-known rule of thumb, not a performance figure; your POH/AFM performance charts give the figures to use.
Why does high density altitude matter?
Thinner air means less lift from the wings, less thrust from the propeller, and less power from the engine, so takeoff and landing rolls lengthen, climb rate drops, and true airspeed rises for the same indicated airspeed. On a hot, high day at a short strip, density altitude is a genuine safety issue — accidents happen when pilots plan for sea-level performance they don't have.
What is pressure altitude and how do I find it?
Pressure altitude is the altitude your altimeter reads when it's set to the standard pressure of 29.92 inHg (1013.25 hPa). You can read it by momentarily setting 29.92 in the Kollsman window, or estimate it from field elevation and the current altimeter setting. Enter that value and the outside air temperature, and the calculator does the rest — a planning estimate, so verify with your POH.