Stock Average / DCA Calculator

Average price = Total amount invested / Total shares purchased. Example: bought 100 shares at $50 ($5,000), then 200 at $40 ($8,000), then 150 at $30 ($4,500). Total invested = $17,500. Total shares = 450. Average = $17,500/450 = $38.89. This is your cost basis per share — the breakeven price. Selling above this is profit; below is loss. Average price changes with every new buy. Useful for tracking dollar-cost averaging, averaging down, or calculating tax cost basis. The calculator updates average automatically with each transaction.

Dollar Cost Averaging (DCA) means investing a fixed amount at regular intervals regardless of market level. Example: $1,000 monthly into a stock or fund — buys more shares when prices are low, fewer when high, smoothing out average cost. Over time, this often produces a better average price than trying to time the market. DCA reduces emotional decisions and timing risk. SIPs in India are DCA. Best for long-term investors who don't want to monitor markets daily. Lump sum can outperform DCA in rising markets but loses to DCA in volatile or declining markets. The calculator simulates DCA outcomes.

Cost basis = Total cost of all shares purchased (including fees and commissions) divided by total shares. Each lot has its own cost basis if tracked separately. Two methods: Average cost (mutual funds typical) or Specific identification (used for stocks). Example: bought 100 shares at $50 + $5 commission = $5,005 cost basis ($50.05/share). Then 100 more at $60 + $5 = $6,005. Total cost basis = $11,010 for 200 shares = $55.05/share. For tax purposes in the US, FIFO is default unless you specify lots. The calculator tracks cumulative cost basis across multiple buys.

Averaging down means buying more shares of a stock you already own at a lower price, reducing your average cost. Example: bought 100 shares at $50 ($5,000), stock drops to $30. Buy 200 more at $30 ($6,000). New average: ($5,000+$6,000)/300 = $36.67. Now you only need the stock to recover to $36.67 (not $50) to break even. Risk: if the company is fundamentally deteriorating, you're throwing good money after bad. Average down only when you have strong conviction in the underlying business. Don't average down on speculative or weakening stocks. The calculator shows new break-even prices.

Statistically, lump sum investing outperforms DCA about 65-70% of the time over long periods, because markets generally rise. If you have $100,000 and invest it all on day one in an 8% growing market, it grows faster than spreading it over 12 months. However, DCA reduces regret and timing risk. If markets drop right after a lump sum, you feel terrible. DCA also forces discipline. For most retail investors, DCA's emotional benefits outweigh statistical inefficiency. For windfalls, a hybrid approach (50% lump sum, 50% DCA over 6-12 months) balances both.

Brokerage fees, transaction costs, and bid-ask spreads all increase your effective average price. Example: buying $5,000 of stock with $20 commission means you've effectively paid $5,020 — your average cost is slightly higher than the quoted share price. Over many transactions, this compounds. STT (in India), STCG/LTCG tax, GST on brokerage all matter. Discount brokers reduce this drag significantly. For active traders, fees can eat 1-3% of returns annually. Always include fees in cost basis for accurate average and ROI calculations. The calculator includes optional fee inputs.

When selling part of a position, calculate proceeds minus cost basis of those specific shares. In the US, default is FIFO (first in, first out). Example: bought 100 at $50, then 100 at $60, then sold 50 shares at $80. Under FIFO, those 50 came from the first lot at $50 — profit = ($80-$50) × 50 = $1,500. Remaining holdings: 50 shares at $50 + 100 shares at $60 = 150 shares, total cost $8,500, average $56.67. You can specify lots (specific ID) to manage tax. The calculator handles partial sales and remaining cost basis.