Total fertility rate versus general fertility rate

Key differences

Difference type	For TFR	For GFR
essential purpose	describing how many children a female would have if at each age she behaved like the average of the woman currently at that age	describing how many children have been added in a particular year, relative to the number of women
relation with age-specific fertility rates	it is a total	it is a weighted average
relation with age-specific fertility rates, weighting used	we use a weighting of 1, i.e., we just add up the ASFR values	we weight by the population of women of that age
scaling used to express the value	scaled to a denominator of 1, i.e., we report the TFR per woman	scaled to a denominator of 1000, i.e., we report the GFR per 1000 women. This is simply because the GFR value per woman would be too small, and we generally prefer to use a scaling where we get reasonably large and easily comparable numeric values.