My salary is 34,500 for 40 hours, what formula can I use to find out what is my salary for 39 hours then ?
I already tried this,
per week = 512.06 using website http://www.thesalarycalculator.co.uk/salary.php
then per day = 512.06 / 5 = 102.412
per hour = 102.412 / 8 = 12.8015
but how can I calculate it if my hours per week are 39 not 40
You work 40 hours a week, and your salary is \$34,500 per year. Assuming you work all 52 weeks in a year, you work $40 \times 52 = 2080$ hours per year.
Therefore, your hourly rate is: $\$34,\!500 / 2080 = \$16.59$ per hour.
So if you work 39 hours per week, 52 weeks a year, your salary will be $\$16.59 \times 39 \times 52 = \$33,\!667.50$