First-principles calculations based on Density Functional Theory have been done on the Tin dioxide - [SnO2]. The Orthorhombic structure of Tin dioxide has been simulated and the optimized structural parameters have been found out. Electron Density of States (EDOS) has been computed in the material using the Electronic structure calculation code of Quantum- Espresso which gives a Band gap of 1.82 eV. This value is close to the value exhibited by TCO, NLO and liquid crystalline materials. Dielectric constant of the material has been computed. The average value of dielectric constant in Tin dioxide comes out to be 8.22. Phonon modes have also been computed.