Here we present multiple-wavelength digital holographic interferometry with a wide measurement range using laser diodes. Small wavelength differences can be easily realized by the wavelength tuning of laser diodes with injection current controls. A contour map of an object with a wide measurement range and a high sensitivity is demonstrated by combining a few contour maps with several measurement sensitivities. Synthetic wavelengths are calibrated using a known height difference. This alleviates the need to have high precise knowledge of the recording wavelengths. The synthetic wavelengths ranged from $\sim 3\mathrm{mm}$ for high measurement sensitivity to $\sim 4\mathrm{cm}$ for wide measurement range. An rms error of $\sim 35\mathrm{\mu m}$ for a $\sim 1\mathrm{cm}$ height measurement is shown. The measured profile of holographic interferometry agrees with a standard stylus instrument.