I haven't done that in 20 years or so! I saw some other lawn guy at the gas station last week and the guy was measuring the oil to add to the 5 gallon gas can, I thought to myself I can't remember the last time I measured the oil. I can eye ball it good. I'v mixed thousands of gallons of gas with oil for the 2 cycle engines with out measuring and have never have a engine wear out. I'm sure I mix rich and have never had any engine or carburetor problems. All my tools seem to have a different mix ratio, and they all get what I give them and they work great! In fact the body or the gears or tires wear out first.