One of the most concrete implications of the discovery of the Higgs boson is that, in the absence of physics beyond the standard model, the long-term fate of our universe can now be established through precision calculations. Are we in a metastable minimum of the Higgs potential or the true minimum? If we are in a metastable vacuum, what is its lifetime? To answer these questions, we need to understand tunneling in quantum field theory.This talk will give an overview of the interesting history of tunneling rate calculations and all of its complications in calculating functional determinants of fluctuations around the bounce solutions. Several problems have persisted for the last four decades, and we present new solutions to these problems that enabled us to calculate exact closed-form expressions of the functional determinant. Applied to the Standard model, we then get the first-ever complete calculation of the lifetime of our universe.