How big is the observable universe?

The observable universe is about 13.7 billion light years from end to end, but it is estimated that theactual universe has a diameter of 156 billion light years, with a radius of 78 billion light years and a circumference of 312 billion light years Answer 13.7 BLY is wrong that is the age of the Universe and it has been expanding exponentially ever since... The comoving distance from Earth to the edge of the visible universe (also called particle horizon) is about 14 billion parsecs (46.5 billion light-years) in any direction. This defines a lower limit on the comoving radius of the observable universe, although as noted in the introduction, it's expected that the visible universe is somewhat smaller than the observable universe since we only see light from the cosmic microwave background radiation that was emitted after the time of recombination, giving us the spherical surface of last scattering (gravitational waves could theoretically allow us to observe events that occurred earlier than the time of recombination, from regions of space outside this sphere). The visible universe is thus a sphere with a diameter of about 28 billion parsecs (about 93 billion light-years). Assuming that space is roughly flat, this size corresponds to a comoving volume of about 3×10⁸⁰ cubic meters. === Misconceptions === Many secondary sources have reported a wide variety of incorrect figures for the size of the visible universe. Some of these are listed below. * 13.7 billion light-years. The age of the universe is about 13.7 billion years. While it is commonly understood that nothing travels faster than light, it is a common misconception that the radius of the observable universe must therefore amount to only 13.7 billion light-years. This reasoning only makes sense if the universe is the flat spacetime of special relativity; in the real universe, spacetime is highly curved on cosmological scales, which means that 3-space (which is roughly flat) is expanding, as evidenced by Hubble's law. Distances obtained as the speed of light multiplied by a cosmological time interval have no direct physical significance.
78 billion light yrs wide