My state has no formula. The amount of spousal support--if any is even awarded--depends on the length of the marriage, the ability of the recipient to earn a living (i.e., age, health, work experience), the ability of the payee to afford the support, and any other special circumstances.
In a few states, lifetime support is the norm for a long-term marriage with a stay-at-home mother/wife. In many other states, a few years of rehabilitative support is the norm.
[This message edited by josie11 at 2:36 AM, October 31st (Thursday)]