P/E: how many years of earnings you're paying for
What P/E means
P/E — Price-to-Earnings — is the most quoted valuation ratio there is: how many rupees is the market charging for every rupee of a company’s annual earnings? Framed differently, it’s roughly how many years of current profit an investor is paying for at today’s price.
The formula
P/E = Price per Share / EPS
This series always uses diluted EPS — the last post showed exactly why that matters.
Worked example: Desi Bites Foods Ltd
| IPO Price | ₹640 |
| ÷ Diluted EPS | ₹16.72 |
| P/E | 38.3x |
Worth seeing the mistake explicitly: had we used undiluted EPS (₹20.9) instead, P/E would come out to 30.6x — a materially different, and wrong, number for a stock that just diluted its share count via a fresh issue.
Worked example: Britannia Industries
Price is Britannia’s NSE closing price on 30 June 2025 (source: Yahoo Finance historical data), paired with the FY25 EPS from the audited consolidated results — i.e. roughly what the market was paying for Britannia’s FY25 earnings shortly after those results were digested. For illustration only, not a signal to act on.
| Price (30 June 2025) | ₹5,851.0 |
| ÷ EPS | ₹90.45 |
| P/E | 64.7x |
A P/E of 64.7x means the market was pricing Britannia at roughly 64.7 years of its FY25 earnings. That’s a rich multiple — but not an irrational one for a company that, across this whole series, has shown ROE above 50%, negative net debt, and a negative cash conversion cycle. A high P/E is what a market paying up for genuine, demonstrated quality looks like — whether 64.7x specifically is a good price to pay for that quality is a separate question this series deliberately doesn’t answer.
Common mistakes
- Treating high P/E as automatically overvalued, or low P/E as automatically cheap. Both readings skip the actual question: is the multiple justified by the quality and durability of the earnings behind it? A “cheap” P/E on a deteriorating business can be far riskier than an “expensive” one on a genuinely strong one.
- Mixing trailing and forward EPS without checking which is being used. This series always uses trailing (historical, already-reported) EPS — some sources quote forward (analyst-estimated) EPS instead, which produces a different P/E for the same price.
- Comparing P/E across industries or growth profiles without context. A slow-growing utility and a fast-growing FMCG brand can both have “reasonable” P/Es that mean completely different things.
- Ignoring earnings quality behind the E. A great P/E on paper means little if the earnings themselves aren’t backed by real cash — worth checking OCF/PAT before trusting a P/E at face value.
Takeaway: P/E measures how many years of current earnings the market is charging for a share — useful as a starting comparison, but it only means something once it’s read alongside the quality and growth of the earnings underneath it, not as a number that’s simply “high” or “low” in isolation.
This post is for educational purposes only and is not investment advice. Wealth Primer explains concepts, not recommendations — nothing here is a suggestion to buy, sell, or hold any specific security or fund. The author is not a SEBI-registered Research Analyst or Investment Adviser. Any prices or figures used as worked examples are historical and shown only to illustrate a calculation. Past performance does not indicate future results. Please do your own research or consult a registered adviser before making investment decisions. See the privacy & disclaimer policy for more.