Simplicity’s seam & hem allowances are all included in
each pattern piece, but are not marked as actual lines. The
standard seam allowance given is 5/8" unless noted
differently. Hem allowances vary and depend on each
individual garment; hem allowances are noted as text on the
pattern tissue.
In the pant leg itself there is a horizontal double line; this
is the lengthening & shortening line, which allows you to
make the pants longer or shorter, depending on your height
and personal preference. Why not just add on or chop off
what you need at the hem? Look at the pattern piece and
you’ll notice that it tapers slightly. Merely adding or
subtracting at the hem will change the shape and overall
appearance of the finished product.