By placing your hand into your machine's drum, you can see how much space is left. Perfect is if you can fit nothing else in the drum, just your hand and your wash. If you can't get your hand into the drum, then it's overloaded.

How full is too full for a washing machine?

Don't Overload the Machine

Even a large load of laundry should not fill the washer tub more than three-quarters full. For a front-load washing machine, pile clothes up high, but don't cram them past the last row of holes at the front (the row closest to the door).

What is an overloaded washer?

What happens if you overload your machine? When you overload your washing machine, you put extra strain on your appliance. Because everything's rammed into the drum, clothes won't be free to move around and get evenly clean. ... An undersized load will put your appliance off-balance during the spin cycle.