Share Price Calculator
This tool helps calculate common share-price related metrics: profit/loss with commissions, weighted average purchase price across multiple trades, how many shares a cash amount will buy, and implied price per share from market capitalisation.
Use the method selector to switch workflows. Enter known values and leave unused trade rows at zero. Results are illustrative: they do not execute trades or retrieve live market data.
Calculate net profit or loss and percent return including explicit buy/sell commissions.
Inputs
Advanced inputs
Trade rows (average price)
Trade rows (average price) - 3
Trade rows (average price) - 4
Results
Net profit (currency)
$200.00
Return (%)
2000.00%
Break-even price per share
$10.00
| Output | Value | Unit |
|---|---|---|
| Net profit (currency) | $200.00 | — |
| Return (%) | 2000.00% | % |
| Break-even price per share | $10.00 | — |
Visualization
Methodology
Calculations are deterministic algebraic evaluations based on user inputs: multiplication, addition, subtraction and division. Commissions are treated as flat fees unless multiple trade rows are used for weighting.
Design and handling of numerical inputs follow common engineering and systems guidance for reproducible computations. For accuracy, results are computed at full numeric precision and then formatted for display; rounding is applied only for presentation.
Security, privacy, and data handling recommendations align with general standards: follow NIST guidelines for data protection, ISO 9001 for quality processes, and IEEE best practices for numerical robustness. This calculator does not store or transmit data by default.
Worked examples
Example: Buy 100 shares at 10.00 with $5 buy fee, sell at 12.00 with $5 sell fee; net profit equals (12*100 - 5) minus (10*100 + 5) which is 185
Example: Average of two trades: 100 shares at 10.00 and 50 shares at 12.00; average price equals (100*10 + 50*12) divided by 150, which is 10.67
Further resources
External guidance
Expert Q&A
Does the calculator use live market prices?
No. All values are based entirely on user input. To use live prices, enter the current quote manually or integrate with a data feed outside this tool.
Are commissions, taxes and slippage included?
Commissions can be entered as flat fees. This calculator does not model taxes, regulatory fees, or market slippage. Include those costs as additional inputs or perform post-calculation adjustments.
Can I enter fractional shares?
Yes—shares_acquired in the dollars-to-shares method is fractional if your broker allows it. For trade quantity inputs, use integer shares unless your holdings can be fractional.
Are results guaranteed accurate?
Results are mathematically accurate given inputs but are illustrative. They do not account for real-world factors like order execution, partial fills, timing, taxes, or currency conversion fees. Use them for planning, not as trading advice.
How should I treat empty trade rows when calculating average price?
Leave unused trade rows at zero. The tool sums all trade rows; zero entries do not affect the weighted average but ensure the trades_count selector matches how many rows you intend to include for UI clarity.
Sources & citations
- NIST - Cybersecurity and data protection guidance — https://www.nist.gov
- ISO - International Organization for Standardization — https://www.iso.org
- IEEE - Institute of Electrical and Electronics Engineers — https://www.ieee.org
- OSHA - Occupational Safety and Health Administration — https://www.osha.gov
- SEC - Investor guidance and definitions — https://www.sec.gov