These linen apron ties are 1/4" wide and 3 yards long.  They are narrow enough to be inserted into the waistband and removed if necessary.  They are hemmed on each end to prevent unraveling.  If you prefer to have two separate apron ties and tack them into each end of your apron, simply cut these in half.
 
This is an historically accurate apron tie pattern based off of extant ties featured in 'Rural Pennsylvania Clothing' by Ellen Gehret.  These ties are period correct for both the 18th and 19th centuries.