Self confidence and self esteem are related emotions but there are wide differences. Self confidence is believing you can accomplish the work you must do and self esteem is feeling worthy whether or not you are capable of doing the work at hand. In other words, what you can do as a person which relates to outside forces such as education, environment, etc., does not interfere with your value as a person. Essentially this is thought over action. Although each involves knowledge, self confidence has more to do with individual actions or performance, and self esteem is how one generally thinks of one's self. A person may have sufficient self esteem to function well overall, but may lack self confidence when attempting to perform when they are ill equipped to perform.
Self confidence can be manipulated outwardly, while internally it will be lacking. Self esteem is more generally accurate, although it is how one thinks of their own abilities and is not something that is decided from outside, and by others. As an example, one of low self esteem may be self-confident, but have low self esteem. That may be possible because they have sufficient knowledge to see them through their daily chores, and their interactions with others, but may not like the way their life unfolds.
To get a better picture of how each differ, and how they are alike, consider their synonyms. Self confident people are self assured, and they trust in their own ability; people with self esteem value themselves and may regard themselves rightly, and respect their own opinions, doing this because they show the same courtesy to others.
Confidence is from the Latin word, confider and is to trust, to believe in; esteem is Middle French, estimer, and from Latin, aestimare, meaning to value. Therefore, in another sense, when looking at the two words according to their sources, confidence is to esteem as trust is to value. Apply that to self and see the difference between trusting yourself and valuing yourself. It is possible to have both at variable degrees during different times in one's life, and at other times to have or the other be lesser or greater than the other.
To get clearer pictures of how these two personal qualities differ, consider the following quotations gleaned from the Quote Garden:
A self confident person is also a successful person and who is not thrown off course by negative criticism. "A successful person is one who can lay a firm foundation with the bricks that others throw at him or her. " by David Brinkley
Self-esteem begins here: "It's not who you are that holds you back, it's who you think you're not." Author Unknown
Self esteem ignores the voices it does not want to hear: It ain't what they call you, it's what you answer to. by W.C. Fields
Self-Confidence saves the day: Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted. by Ralph Waldo Emerson
Self-esteem is from inner sources: "People are like stained-glass windows. They sparkle and shine when the sun is out, but when the darkness sets in their true beauty is revealed only if there is light from within." by Elisabeth Kübler-Ross
Self-esteem does not need outer adornment: Do not let your adorning be external—the braiding of hair and the putting on of gold jewelry, or the clothing you wear— but let your adorning be the hidden person of the heart with the imperishable beauty of a gentle and quiet spirit, which in God's sight is very precious. From 1 Peter 3:3-4 ESV
Self confidence is necessary for the long journey: But they that wait upon the Lord shall renew their strength; they shall mount up with wings as eagles; they shall run, and not be weary; and they shall walk, and not faint.