Albert Barnes Commentary Exodus 16:18

"And when they measured it with an omer, he that gathered much had nothing over, and he that gathered little had no lack; they gathered every man according to his eating." — Exodus 16:18 (ASV)

Had nothing over - Whatever quantity each person had gathered, when he measured it in his tent, he found that he had just as many omers as he needed for the consumption of his family.