The patriots saw the Battle of Bunker Hill as a success because they held their ground against several charges of the British and inflicted heavier casualties than they themselves sustained. The engagement boosted the confidence of the patriots and slowed down the overall British advance.
After hearing that the British intended to seize and occupy the high ground around Boston, about 1,000 to 1,200 colonists commanded by Colonel William Prescott fortified Breed's Hill, near Bunker Hill. Around 2,200 to 3,200 British troops under Major General William Howe attacked the American defenders on June 17, 1775. To conserve ammunition, Prescott famously told the colonists not to shoot until they saw the whites of their enemy's eyes. Heavy American musket fire caused the first two British advances to retreat, but on the third advance, the colonists ran out of ammunition. Because the British had bayonets, they had the advantage in the hand-to-hand fighting that ensued, and the Americans were forced to retreat.
The battle encouraged the Americans that they could take a stand against the British. Although the British won the hill, their casualties were over 200 killed and 800 wounded, as opposed to just over 100 killed and 300 wounded for the Americans. Because of their losses, the British held back instead of advancing to capture Dorchester Heights overlooking Boston. Months later, George Washington and his colonial army seized Dorchester Heights and used the advantage to force the British out of the Boston area altogether.