Estimating a table size

Hello all,

I need a tool or something like it, which can give me the estimated size
of a table considering all fields, constraints, indexes, etc...

For example:

CREATE TABLE products (

product_id INT8,

product_name VARCHAR(50),

product_vendor VARCHAR(50),

price NUMERIC(10,2),

CONSTRAINT pk_products PRIMARY KEY (product_id),

CONSTRAINT ck_price CHECK (price >= 0)

);

CREATE INDEX ix_products ON products (product_name);

See that in the example above I have, some fields, some constraints and
one index. I want to know (estimate) how much fisical space (KB, MB) it will
consume!

Thanks in advance!