What is a stock profit calculator?

A stock profit calculator computes the profit or loss on an equity trade, factoring in purchase price, sale price, quantity, brokerage, taxes, and other charges. For Indian investors, it also computes STCG / LTCG tax based on holding period.

Exchange dashboards typically show gross profit ignoring brokerage and taxes. A real take-home P&L can be 5-15% lower than the headline number, especially for small trades.

How is profit calculated?

gross profit = (sell price − buy price) × quantity
total brokerage = buy brokerage + sell brokerage
total charges = STT + exchange + GST + SEBI + stamp duty
net profit (pre-tax) = gross profit − total brokerage − total charges
tax = STCG (15% × net profit) OR LTCG (10% × profit above ₹1L)
net profit (after tax) = net profit − tax
ROI % = (net profit / total invested) × 100

Worked example

You buy 100 shares of Infosys at ₹1,500 (₹1,50,000) on 1 March 2025. Sell 100 shares at ₹1,800 on 1 May 2025 (held < 12 months → STCG).

Indian charges (Zerodha-style approximation, equity delivery):

Gross profit = (1,800 − 1,500) × 100 = ₹30,000
Net of charges = 30,000 − 413.5 = ₹29,586.5

Holding period: 2 months → STCG applies (15% on net profit)
STCG tax = 29,586.5 × 15% = ₹4,437.98
After-tax profit = 29,586.5 − 4,438 = ₹25,148.5

Headline profit: ₹30,000. Actual take-home: ₹25,149. Difference: ₹4,851 (16% leak).

ROI: 25,149 / 1,50,000 = 16.77% in 2 months.

STCG vs LTCG (Indian equity)

Critical change as of Budget 2024 (effective 23 July 2024):

• STCG: 15% → 20%
• LTCG: 10% → 12.5%
• LTCG exemption: ₹1L → ₹1.25L per year

Long-term hold worked example

You bought 500 shares of HDFC Bank at ₹1,200 in January 2020. Sell at ₹1,800 in January 2026 (held 6 years → LTCG).

Gross profit = (1,800 − 1,200) × 500 = ₹3,00,000
Charges (estimated) = ₹2,000
Net profit = ₹2,98,000

LTCG: exempt up to ₹1,25,000
Taxable LTCG = 2,98,000 − 1,25,000 = ₹1,73,000
Tax (12.5%) = ₹21,625
After-tax profit = 2,98,000 − 21,625 = ₹2,76,375

ROI (6 years): 2,76,375 / 6,00,000 = 46% total
Annualized: ((876,375/600,000)^(1/6) − 1) × 100 ≈ 6.5%/year

After 6 years of waiting, holding through Covid, you net 6.5% annualized. Equities work, but average return matters — a single hot stock isn't representative of portfolio performance.

Indian equity charges explained

Full breakdown is on Zerodha's brokerage calculator — these add up to ~0.3-0.5% per round-trip for most retail trades.

Worked example: small trades hurt

You buy ₹5,000 worth of a small-cap stock. Sell at 5% gain (₹5,250 sell).

Gross profit = ₹250
Charges (round-trip): roughly ₹25 brokerage + ₹50 other = ₹75
Net pre-tax profit = ₹175
STCG tax (20%) = ₹35
Net after-tax = ₹140
ROI: 2.8% — not 5%

Small trades have disproportionate fee impact. Better strategy: trade in larger lots, or use mutual funds for small amounts.

Other markets

US stocks (via Indian brokers)

• Brokerage: ~$0-5/trade (Interactive Brokers, Vested)
• Foreign tax: ~25% on dividends (treaty rate, refundable via DTAA)
• Indian tax: same STCG/LTCG rules — Foreign equities held > 24 months = LTCG
• FX cost: 0.5-1% spread on USD conversion both ways

Intraday equity (no holding overnight)

• STT lower (0.025% on sell only)
• Always STCG (not eligible for LTCG)
• Brokerage lower (~₹20 fixed)
• DP charges nil
• Higher margins / leverage available

F&O (futures and options)

• STT: 0.02% on options (sell only)
• Tax: treated as business income, not capital gains — applies your slab rate
• More complex tax treatment, often requires CA help

Components and inputs

Buy price + buy quantity

Total invested = price × quantity.

Sell price + sell quantity

Should usually match buy quantity (partial sell handled by entering only the sold portion).

Holding period

The calculator infers STCG vs LTCG. Or set explicitly.

Brokerage (optional)

Per-trade brokerage. Defaults to ₹20 flat (discount broker estimate).

Other charges (optional)

Lumped or separately. Default: 0.05% of trade value as a rough total of STT + exchange + SEBI + stamp + GST.

Tax preference

• Auto (detect STCG vs LTCG by holding period)
• Force STCG
• Force LTCG
• Skip tax (compute pre-tax only)

Considerations

• Tax timing matters. If you crossed the ₹1,25,000 LTCG exemption already this year, additional LTCG is taxed from rupee one — plan large sells across financial years.
• Buyback / dividend / bonus issues complicate cost basis. The calculator handles simple buy-sell only.
• Selling losing stocks in the same FY as winners helps offset (STCG losses against STCG/LTCG gains; LTCG losses against LTCG only). Plan loss harvesting before March 31.
• Long-term capital losses carry forward 8 years.

Limitations

• Doesn't handle bonus shares, rights, splits, mergers (need cost-basis adjustment).
• Doesn't handle ESOPs / RSUs (different tax treatment — perquisite + capital gains).
• Doesn't model F&O business-income tax.
• Doesn't optimize trade timing for tax (calculator is descriptive, not prescriptive).

Related calculators

• Stock Average — DCA / repeated buys
• CAGR — annualized return
• ROI — generic return %
• Income Tax — slab math
• SIP — recurring mutual-fund investment
• Mutual Fund Returns — long-term wealth building

Final note. Headline profit ≠ take-home profit. Always model brokerage + STT + tax before celebrating a winning trade. For Indian equity, LTCG is dramatically more efficient than STCG — favor holding ≥ 12 months when possible, and harvest the ₹1.25 lakh LTCG exemption every year. The single biggest lever for long-term equity wealth: lower turnover, longer holds, lower taxes.