Stock Profit Calculator
Work out what a trade actually made after commission — then discover that the holding period, not the fees, is what really decides your net.
Stock Profit Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Results are a model, not a quotation — an institution's own figures govern.
- Every input is an assumption; change one and the answer changes with it.
- Rounding is applied only at the display layer, so totals may differ by a cent from a statement that rounds each line.
In short: Buying 100 shares at $45.20 and selling at $68.75 with $4.95 commission each way produces a $2,345.10 profit on a $4,524.95 cost — a 51.83% return. Commission costs $9.90, just 0.42% of the gross gain, while the difference between short and long-term tax treatment is $211.06.
Formula
Q = shares · c = commission per trade. Commission is added to the cost on the way in and deducted from proceeds on the way out, so it is charged twice.
Worked Example
- Build the cost basis. 100 × $45.20 + $4.95 = $4,524.95.
- Net the proceeds. 100 × $68.75 − $4.95 = $6,870.05.
- Take the difference. $6,870.05 − $4,524.95 = $2,345.10, a 51.83% return on cost.
- Annualise it. Over eighteen months that is 32.10% a year, which is the figure comparable with any other investment.
- Apply the right tax rate. Held beyond twelve months it is long-term: $351.77 at 15% rather than $562.82 at 24%, a $211.06 saving.
Analyst's note. Commission is the cost everyone watches and it is trivial here — $9.90, or 0.42% of the gross gain. The holding period is the cost nobody watches and it is worth $211.06, more than twenty times as much. Selling at eleven months rather than thirteen is one of the most expensive habits in retail investing, and it never appears on a statement.
Strengths & Limits Of This Model
Where this engine is strong
- Runs entirely in your browser — no figure you type is transmitted or stored.
- Shows the full working, so every number can be traced and challenged.
- Free, unmetered and free of affiliate incentives.
Where it stops
- Generalised assumptions cannot capture every individual circumstance.
- Jurisdiction-specific rules and mid-year changes may not be reflected.
- A model output is not a substitute for a professional review of your position.
Practical Use Cases
Checking a trade before you place the sell order
Enter your actual entry, the current price and your holding period. If you are inside twelve months, the engine shows precisely what waiting would save. Confirm the tax bands that apply to you with the Capital Gains Calculator.
Finding your true break-even price
Commission on both sides means you need more than your entry price simply to get out level — $45.30 here, not $45.20. On small positions with fixed commissions that gap is much wider, which is a strong argument against very small trades.
Comparing trades of different lengths
A 51.83% return means nothing until it is annualised: over eighteen months it is 32.10% a year, over five years it would be 8.71%. Use the annualised figure to compare against any other holding, or against the market with the CAGR Calculator.
Methodology & Editorial Standards
Commission is applied on both legs — added to the purchase cost and deducted from the sale proceeds — which is the correct treatment for computing an economic return and also matches the US cost-basis convention. The annualised figure is the geometric rate implied by the proceeds-to-cost ratio over the holding period, not a simple division, so it is directly comparable with any other compound return. Long-term treatment is applied beyond twelve months, following the US rule; other jurisdictions differ. Dividends received during the holding period, wash-sale rules, per-share commission structures and state taxes are not modelled. The engine implements the standard published formula for this calculation. Inputs are validated for domain and sign before evaluation, and any undefined case returns an em-dash rather than a spurious value.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Stock Profit Calculator — 20 Expert FAQs
20 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How do I calculate profit on a share trade?
Net proceeds minus total cost basis. Commission is added to what you paid and subtracted from what you received, so it hits twice: 100 shares from $45.20 to $68.75 with $4.95 each way gives $2,345.10 on a $4,524.95 basis.
What is my break-even price?
The price at which proceeds after commission equal your cost basis — $45.30 here against a $45.20 entry. The gap widens sharply on small positions, because a fixed commission is a much larger percentage of a small trade.
Why annualise a return?
Because 51.83% over eighteen months and 51.83% over five years are wildly different outcomes. Annualising converts both to a comparable yearly rate — 32.10% here — which is the only fair basis for comparing holdings of different lengths.
How much does the holding period matter for tax?
A great deal. Crossing twelve months moves a US gain from ordinary income rates to long-term capital gains rates: $562.82 against $351.77 here, a $211.06 saving on a $2,345.10 profit for waiting a few weeks longer.
Is commission a big deal?
Rarely, at modern rates — $9.90 is 0.42% of the gross gain here. It matters most on small or frequently traded positions. Bid-ask spread and tax treatment are almost always the larger costs, and both are less visible.
What is the wash-sale rule?
A US rule disallowing a loss if you buy a substantially identical security within thirty days before or after the sale. The disallowed loss is added to the new position's basis rather than lost, but the timing benefit is deferred. Not modelled here.
Does this include dividends?
No — it measures the capital gain on the trade only. If the position paid dividends, your total return is higher than shown. Use the Dividend Calculator to model the income component separately.
What if I sell at a loss?
The engine reports the loss in accounting parentheses and applies no tax, since there is no gain. Realised losses can generally offset gains elsewhere and, in the US, a limited amount of ordinary income, with the excess carried forward.
How do I handle multiple purchases at different prices?
Either run each lot separately, or enter your weighted average cost as the buy price. Which lots you are deemed to sell — FIFO, specific identification — has real tax consequences, so check your broker's default setting.
Are these figures before or after tax?
The headline profit is after commission and before tax; the after-tax output applies the rate matching your holding period. State taxes, the net investment income tax and foreign withholding are not included.
What return should I be aiming for?
Judge it against a passive benchmark over the same period rather than against zero. A 32.10% annualised return is excellent; the relevant question is whether the strategy repeats, and whether the risk taken was proportionate.
Should I hold just to get the lower tax rate?
Only if you would hold anyway. Tax is a reason to delay a marginal sell decision by a few weeks, never a reason to keep a position you believe is overvalued. A 9-point tax saving does not cover a 20% price fall.
What is the difference between realised and unrealised gains?
Realised gains come from a completed sale and are taxable. Unrealised gains exist only on paper and are not. This engine models a completed round trip, so everything it reports is realised.
Does the bid-ask spread matter?
Yes, and it is often larger than commission on less liquid stocks. You buy at the ask and sell at the bid, so the spread is a real round-trip cost. Include it by adjusting your entry and exit prices slightly against yourself.
How is the annualised figure calculated?
As the geometric rate: proceeds divided by cost, raised to the power of one over the years held, minus one. Simple division would overstate short holdings and understate long ones, sometimes dramatically.
Is this stock profit calculator free to use?
Yes. It is free, requires no account, and has no usage limits. ApexConverter is funded by contextual advertising, never by selling user data.
Is my data sent to a server?
No. The engine runs as Vanilla JavaScript inside your browser under our Zero-Server Client-Side Execution model. Your figures are computed locally and are never transmitted, logged, or stored.
How accurate is this calculator?
It applies the standard closed-form formula in IEEE-754 double precision, rounding only at the display layer. The engine is reconciled against an independent reference implementation before release.
Does it work on mobile?
Yes. The interface is mobile-first with numeric keypad hints and is tested down to a 320-pixel viewport with no horizontal scrolling.
Can I use it offline?
Largely, yes. Because computation is client-side, the page continues to calculate without a network connection once it has loaded.