The APE Calculator helps to easily evaluate often needed equations in ultrafast and nonlinear laser optics. This includes Sum Frequency Generation (SFM, SFG), Difference Frequency Generation (DFG), the wavelength relations in an optical parametric oscillator or amplifier (OPO, OPA) as well as in coherent anti-Stokes Raman scattering (CARS) or SRS spectroscopy. The conversion between wavelength, wavenumber, photon energy and frequency as well as different characterizations of pulses can be calculated, e.g. bandwidth, time bandwidth product, pulse duration or dispersion. Conversion of peak and average powers, pulse energy and pulse energy density, repetition rate and beam diameter as well as power densities is possible. Feedback as well as feature requests are appreciated.