I need help understanding the negative caloric goal.?

If I eat 1400 calories a day, how many calories do I need to burn each day to lose weight? I've seen the 500 negative caloric balance, but do I really need to burn 2100 calories a day to lose 1 lb per week? My pedometer yesterday told me I burned a whole whopping 235 calories all day. According to a step chart, 100 calories = 2000 steps. For 2100 calories, that's 42000 steps daily which I'm having a hard time fathoming. So I'm hoping I am misunderstanding the formula, or that my pedometer is broken...otherwise I have an enormous challenge ahead of me. Please help me make sure I am understanding this correctly.