Fixed menu and anchors, how to do?

Should I have a fairly typical task.
There is a fixed floating menu with anchors.
At the anchor we moved to the block with id.
But what I can't cope.

When scrolling to the desired block, the block is partially hidden under the menu.
Since the block is nailed to the top of the page.
And as it is nailed to the top of the page + the height of the menu?

$('a[href*="#"]').bind("click", function(e) {
 var anchor = $(this);
 $('html, body').stop().animate({
 scrollTop: $(anchor.attr('href')).offset().top
 }, 1000);
e.preventDefault();
 });