Pipeline coverage is a ratio used by sales managers to measure how much pipeline they have, compared to how much quota they need to close. It's calculated by dividing your open pipeline by how much quota you have to close. General rule of thumb is to have 3x to 4x pipeline coverage. This means you want to have 3 to 4 times more pipeline than quota.
Forecast coverage measures your weighted forecast, relative to your quota for a given period of time. To measure forecast coverage, you take your forecast for a period, and divide by your quota for that same time period.
For example, if a rep is forecasting $120,000 for Q2 and their quota for Q2 is $125,000, then their forecast coverage is $120,000 / $125,000 = 96%. This rep is projecting to close 96% of their quota.