If plate tectonics exists on Venus, the rate of topographic dropoff from spreading centers should be about half that on Earth due to greater rock: fluid density contrast and lower temperature differential between the surface and interior. Using 10¿10 mean elevations, 21,000 km of ridge were identified on Venus and 33,000 km on Earth. Heights h at distances up to ~1000 km to either side of the ridges were analyzed to make least squares determinations of the parameters h0, Δh, and n in: h = h0-Δh sn, where s is off-crest distance. The Venus ridges have a much less well-defined mode in crest heights h0 than the Earth ridges, and a somewhat smaller exponent n, on the average, indicating greater concavity. Fixing n to the theoretical value of 0.5, plate velocities were inferred from the Δh's, using ∂h/∂(t1/2) from North Atlantic and North Pacific data. On Earth, these velocity solutions were compared to those from plate rotations, which indicate the ∂h/∂(t1/2) is probably about 40% too high for a global mean. The resulting plate creation rates on Venus (assuming comparable total heat generation and taking into account the density and temperature differences) are 0.7 km2/yr or less, and indicate that not more than 15% of Venus's energy is delivered to the surface by plate tectonics, in contrast to 2.9 km2/yr and 70% energy delivery on Earth.