AIM Investments has upgraded the advisor section of its Web site with a new self-employed persons' calculator that compares maximum contribution guidelines for Solo 401(k) plans, profit sharing plans, SIMPLE, and SEP individual retirement accounts.

The calculator, which was developed by Pensiononline.com, a San Francisco software developer, puts solo 401(k)s in a favorable light with higher maximum contributions and larger payouts that alternative plan choices. The calculator sells for an upfront $1,500 licensing fee with $495 subsequent annual installments, said a Pensionline.com marketing official.

Running hypothetical illustrations is a fairly straightforward matter requiring only three pieces of information: age, income and business type. Finished illustrations include bar charts comparing maximum contribution limits for each plan option.