Fractional uncertainty on H₀ (red line) for a future kilonova detection with similar intrinsic luminosity, systematic uncertainties, and peculiar velocity uncertainty as AT2017gfo. The dominant contribution for objects at D_L < 100 Mpc is the uncertainty from peculiar velocities (dashed orange line) assuming the total peculiar velocity uncertainty is independent of the distance. The statistical uncertainty on the luminosity distance for mock spectra objects with the same intrinsic luminosity as the first X-shooter epoch increases with distance (blue dotted lines). The systematic uncertainties in distance from sphericity constraints, flux calibration, and dust extinction are considered to be independent of the source distance.