Most tapes are marked in 16ths, 8ths, quarters and halves. 5/16 would be the fifth mark from the end. You can be sure of this if your tape has 15 marks before the one inch mark; each one of these marks is 1/16 of an inch.
Where Is The 5\16 On A Tape Measure?
A tape measure is broken into feet then inches, the inches are broken up accordingly you are interested in 16ths so there are 16 in an inch 8 in a half inch 4 in a quarter inch, so the little tiny mark just past the quarter inch mark is 5/16ths.