We show that first-principle calculations with an economic basis set can predict reliable geometric structures and accurate vibrational frequencies for small proton-bound carboxylic acid clusters. This leads to the potential of using limited computational resources to study large molecular systems. Further applications using density functional (DFT) theory on a series of proton-bound formic and acetic acid clusters have found reasonable evaporation energies in comparison with experiments. Our DFT calculations have exactly reproduced the changeover from monomer loss to dimer loss at n = 6 found in an experiment for proton-bound formic acid clusters.