It's a very common dilemma for first time stock buyers. You want to invest in 'safe' stocks yet have no idea about the process involved. Should you trust your broker? Or should you trust the markets analysts. And at the end of the day you are left confused by the myriad of opinions and advices that are thrown at you.

Instead, why not understand the parameters yourself so that you can make the best choice? To help you understand the intricate art of choosing the best stocks to invest in, here are eight key ratios. Read on, understandÂ…and happy investing!

**Ploughback/reserves**: Every year, a company divides its net profit (profit left after subtracting various expenses including taxes) in two portions: ploughback and dividends. While dividends are handed out to the shareholders, ploughback is kept by the company for its future use and is included in its reserves.

Ploughback is essential because besides boosting the company's reserves, it is a source of funds for the company's expansion plans. Hence if you are looking for a company with good growth prospects, check its ploughback figures.

Reserves are also known as shareholders' funds, since they belong to the shareholders. If a company's reserves are twice its equity capital it can then reward its shareholders with a generous bonus. Also any increase in reserves will push the share price of your share.

**Book value per share:** This ratio shows the worth of each share of a company as per the company's accounting books. It is calculated as:

**Book Value per share = Shareholders' funds / Total quantity of equity shares issued**

Shareholders' funds can be computed by subtracting the total liabilities (money owed to creditors) of the company from its total assets. It can also be calculated by adding the equity capital to the company's reserves.

Book value is an old record that uses the original purchase prices of the assets. However it doesn't show the present market price of the company's assets. As a result, this ratio has a restricted use when it comes to estimating the market price of the shares, but can give you an estimate of the minimum price of the company's shares. It will also help you judge if the share price is overpriced or under-priced.

**Earnings per share (EPS): **One of the most popular investment ratios, it can be computed as:

**Earnings Per Share (EPS) = Profit Post Tax / Total quantity of equity shares issued**

This ratio computes the company's earnings on a per share basis. E.g. you own 100 shares of ABC Co., each having a face value of Rs 10.

Assume the earnings per share is Rs 10 and the dividend declared is 30 per cent, or Rs 3 per share. This implies that on every share of ABC Co, you earn Rs. 6 each year, but you actually get Rs 3 via dividend. The balance of Rs 4 per share goes into the ploughback (retained earnings). Had you purchased these shares at par, it implies a return of 60 per cent.

This example shows that instead of looking at the dividends received from to company as the base of investment returns, always look at earnings per share, as it is the actual indicator of the returns earned by your shares.

**Price earnings ratio (P/E):** This ratio highlights the connection between the market price of a share and its EPS.

**Price/Earnings Ratio (P/E) = Price of the share / Earnings per share**

It shows the degree to which earnings of a share are protected by its price. E.g. if the P/E is 40, it means the share price is 40 times its earnings. So if the company's EPS is constant, it will need about 40 years to make up for the purchase price of the share, after taking into account the dividends and the capital appreciation. Hence low P/E means you will recover your money quickly.

P/E ratio shows what the market thinks about the earnings potential and future business forecast of a company. Companies with high P/E ratios are the darlings of the investors and thus enjoy a higher market rating.

In order to use the P/E ratio properly, take into account the future earnings and growth projections of the company. If the current P/E ratio is low, as against the future prospects of a company, then the shares make an attractive investment option.

But if the company is saddled with losses and falling sales, stay away from it, despite the low P/E ratio.

**Dividend & yield: **Dividend is the portion of the profit that is distributed amongst shareholders. Companies offering high dividends, normally don't have much of growth to talk about.

This is because the ploughback required to finance future development is insufficient. Similarly, those companies in high growth sector don't give any dividend. Instead here they give sharp capital appreciation, which ultimately will lead to higher dividends.

So it makes much more sense to invest for capital appreciation instead of dividends. Rather it makes more sense to invest for yield, which is nothing but the association between the dividends and the market price of the shares. Yield (dividend yield) can be calculated as:

**Yield = (Dividend per share / market price of a share) x 100**

Yield shows the returns in percentage that you can expect via dividends earned by your investment at the current market price. It is more useful than simply focusing on the dividends.

**Return on capital employed (ROCE)**: ROCE is the ratio that is calculated as:

**ROCE: Operating profit / capital employed (net value + debt)**

To get operating profit, add old taxes paid, depreciation, special one-off expenses, and special one-off income and miscellaneous income to get the net profit. The operating profit is a far better indicator of the profits earned by the company instead of the net profit.

Hence this ratio is the better indicator of the general performance of the company and the company's operational efficiency. It is one of the most useful ratio that lets you compare amongst the companies.

**Return on net worth (RONW):** RONW is calculated as

**RONW = Net Profit / Net Worth**

This ratio gives you an idea of the returns generated by investing in the company. While ROCE is an effective measure to get a general overview of the profitability of the company's business operations, RONW lets you gauge the returns you can earn on your investment.

When used along with ROCE, you get an overview of the company's competence, financial standing and its capacity to generate returns on shareholders' finances and capital employed.

**PEG ratio: **PEG is an essential and extensively used ratio for calculating the inbuilt worth of a share. It helps you decide whether the share is under-priced, totally priced or overpriced.

To derive the ratio, you have to associate the P/E ratio with the expected growth rate of the company. It assumes that higher the growth rate of the company, higher the P/E ratio of the company's shares. Vice versa also holds true.

**PEG = P/E / expected growth rate of the EPS of the company**

In general, a PEG lesser than 0.5 is a lucrative investment opportunity. However if the PEG exceeds 1.5, it is time to sell.

These are some of the most critical ratios that must be considered when purchasing a share. Extensive reading of the financial performance of the company in newspapers and magazines will help you get all the relevant information to get the correct decision