How long does it take for U-238 to become lead?

Uranium-238 (U-238) undergoes a series of radioactive decay processes over a period of approximately 4.5 billion years to eventually transform into stable lead-206 (Pb-206). This transformation occurs through a series of intermediate isotopes, including thorium-234 and radium-226, among others. The entire decay chain involves multiple steps, but the end result is that U-238 can be considered to reach lead in terms of transformation over geological timescales.