z x c = H x d is the formula I am using to try to convert redshift to megaparsecs, where H I'm taking to be 71km/s/Mpc and c as 299,792.46 km/s. When I plug in .1 for z I get 1.377 Billion Light years (422.2429 Mpc), which sounds right. But when I plug in 10 for z I get the huge distance of 137.717 Billion Light years. Is that because of the comoving universe? I'm really just after the light travel time distance, not really where the galaxy is now. Am I using the wrong formula?