From the rec.sport.tennis FAQ:
USTA Self Rating System
The National Tennis Rating Program provides a simple, initial self-placement
method of grouping individuals of similar ability levels for league play,
tournament, group lessons, social competition and club or community programs.
The rating categories are generalizations about skill levels. You may find
that you actually play above or below the category which best describes your
skill level, depending on your competitive ability. The category you choose
is not meant to be permanent, but may be adjusted as your skills change or as
your match play demonstrates the need for reclassification. Ultimately, your
rating is based upon your results in match play.
To place yourself:
A. Begin with 1.0. Read all the categories carefully and then decide
which one best describes your present ability level. If your abilities
range between two catagories, then choose the lower one.
B. Be certain that you qualify on all points of all preceding categories
as well as those in the classification you choose.
C. When rating yourself assume you are playing against a player of the
same sex and the same ability.
D. Your self-rating may be verified by a teaching professional, coach,
league coordinator or other qualified expert.
E. The person in charge of your tennis program has the right to reclassify
you based upon match results, if your self-placement is thought to be
1.0 This player is just starting to play tennis.
1.5 This player has limited playing experience and is still working
primarily on getting the ball into play.
2.0 This player needs on-court experience. This player has obvious
stroke weaknesses but is familiar with basic positions for singles
and doubles play.
2.5 This player is learning to judge where the ball is going although
court coverage is weak. This player can sustain a slow rally with
other players of same ability.
3.0 This player is consistent when hitting medium pace shots, but is
not comfortable with all strokes and lacks control when trying for
a directional intent, depth, or power.
3.5 This player has achieved improved stroke dependability and direction
on moderate pace shots, but still lacks depth and variety. This
player exhibits more aggressive net play, has improved court coverage,
and is developing teamwork in doubles.
4.0 This player has dependable strokes, including directional intent,
on both forehand and backhand sides on moderate shots, plus the
ability to use lobs, overheads, approach shots and volleys with
some success. This player occasionally forces errors when serving
and teamwork in doubles is evident.
4.5 This player has begun to master the use of power and spins and is
beginning to handle pace, has sound footwork, can control depth of
shots, and is beginning to vary tactics according to opponents.
This player can hit first serves with power and accuracy and place
the second serve and is able to rush the net successfully.
5.0 This player has good shot anticipation and frequently has an
outstanding shot or attribute around which a game may be structured.
This player can regularly hit winners or force errors off of short
balls, can put away volleys, can successfully execute lobs, drop
shots, half volleys and overhead smashes, and has good depth and
spin on most second serves.
5.5 This player has developed power and/or consistency as a major weapon.
This player can vary strategies and styles of play in a competitive
situation and hits dependable shots in a stress situation.
6.0 These players will generally not need NRTP rankings. Rankings or
to past rankings will speak for themselves. The 6.0 player typically
7.0 has had intensive training for national tournament competition at
the junior level and collegiate levels and has obtained a sectional
or national ranking. The 6.5 player has a reasonable chance of
succeeding at the 7.0 level and has extensive satellite tournament
experience. The 7.0 is a world class player who is committed to
tournament competition on the international level and whose major
source of income is tournament prize winnings.
With this list you can rate yourself. Should you realize that your
abilities range between two categories, then the lower one should be used
to determine your playing level.