Grooms now have a diamond engagement ring calculator. Courtesy of GroomGroove.com, they can enter their salary information and with a click of a button, figure out how much DeBeers wishes they would spend on their bride's diamond engagement ring!

Where did the two months of salary idea come from?

The origin of the two months salary begins with DeBeers, the largest diamond producer and marketer in the world. In 1947, in an effort to increase diamond sales in the United States following a depressed wartime market, DeBeers launched a marketing campaign with a New York advertising firm. A copywriter penned the famous slogan "A diamond is forever". As far as advertising slogans go, it's pretty damn good. A diamond, like your marriage, is supposed to last forever. (ed. - We're thankful wedding preparation doesn't last nearly as long.)

From our research, GroomGroove.com understands that DeBeers wanted to bring diamonds to the masses, rather than have them be for a select few. Accordingly, the price of diamonds was set at approximately two months of salary, which is somewhat tied to inflation.

Diamonds, just like your marriage, are an investment, and have been an investment device for several thousand years. Hard, durable and used to mine for other minerals, diamonds are generally quite rare (although they are not the rarest of gemstones). This, coupled with cartelization by the producers and resellers, keeps diamond prices very high. As a result, it will cost a groom at least $1000 to purchase a diamond of decent cut, clarity, color and carat. Of course, a $1000 diamond engagement ring will likely be lacking in two or three of the four C's. Accordingly, a groom is likely to spend at least $2,500 on his bride's engagement ring.

So just how much is two months salary?

While there is no real answer, we believe two months' salary refers to your gross salary, and not your net salary. (ie. the amount of money you make before taxes and deductions).

Here are some sample salaries and diamond engagement ring cost equivalents:

If you earn... $30,000: tradition states you're on the hook for a $5,000 diamond engagement ring. $50,000: rampant advertising suggests you buy a $8,333 rock. $80,000: say goodbye to $14,167 on that piece of ice. $100,000: pray that for $16,667 she sticks around for a long time to come.

And... If you earn $100 billion dollars, or the approximate Gross Domestic Product of New Zealand, you're looking at dropping $16 billion dollars. On the bright side, however, you should be able to get a good quality cut, carat, color, clarity and cardiac arrest at that price!