The take-off calculator gives you an instant overview if a certain runway is long enough under the current conditions. You can adjust external parameters like elevation, QNH, temperature, wind, slope and weight conditions. Pressure altitude and density altitude are calculated and displayed.
The current version uses the density altitude to determine ground run and take-off / landing distances with a quadratic approximation. All other influences are estimated using rule-of-thumb estimators. Customise all internal calculation parameters to your own aircraft in the settings menu to reflect your own situation.