Endpoint (also called indication point) should be as near as possibly be at equivalence point, it is indicated by sudden change of pH or the color of an appropriate indicator.

pH of Equivalence point of strong acid or base analyte is 7.0 (+/- 1.5 unit)

Of weak acids and bases:

pH of Equivalence point of weak acid or base analyte

= (about) 14 - 0.5*[ pKb + pCb ] for weak acid analytes (+/- 1.0 unit)

or

= (about) 0.5*[ pKa + pCa] for weak base analytes (+/- 1.0 unit)

in which

'p' means negative log10(value)

Ka and Kb means acid and base constants (of the analyt conjugated pair)

Ca and Cb means actual acid and base concentration (of the analyte conjugates)

At HALF-WAY equivalence point the pH = pKa, since the actual concentration of ACID is equal to concentration of its conjugate BASE, because both are equal to HALF of the original (= unknown analyte) concentration to be titrated (half left = half formed).