  We describe numerical methods for constructing lump solutions in open string
field theory. According to Sen, these lumps represent lower dimensional
Dp-Branes and numerical evaluation of their energy can be compared with the
expected value for the tension. We take particular care of all higher
derivative terms inherent in Witten's version of open string field theory. The
importance of these terms for off shell phenomena is argued in the text.
Detailed numerical calculations done for the case of general $p$ brane show
very good agreement with Sen's conjectured value. This gives credence to the
conjecture itself and establishes further the usefulness of Witten's version of
SFT .
