Before you can compute your weekly TTD benefits, you have to know your average weekly wage.  Section 287.250 RSMo. sets forth the manner of determining average weekly wage. In a nutshell:

(1)  If wages are fixed by the week, that is the average weekly wage;

(2)   If wages are fixed by the month, the wage is computed by taking the monthly amount, multiplying it by 12 months and then dividing that by 52;

(3)  If wages are fixed annually, take annual wage and divide by 52;

(4)  If wages are earned by the hour, day or by output, then take the amount actually earned in the immediately preceding 13 weeks and divide by 13. (There are a few exceptions to this rule in the case of workers who have worked less than 13 weeks for the employer and for workers who miss more than five regularly scheduled workdays during the 13-week period)

You would receive 2/3 of this average weekly wage while you are off work, up to a maximum amount that changes every year.  As of this writing (December, 2012), the maximum weekly amount a worker can receive for TTD benefits is $827.75.