Fidamen

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.

Updated Nov 4, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 2c5c3aaf8971 • Reviewed by Fidamen Standards Committee

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

Updates as you type

Net profit (currency)

$200.00

Return (%)

2000.00%

Break-even price per share

$10.00

OutputValueUnit
Net profit (currency)$200.00—
Return (%)2000.00%%
Break-even price per share$10.00—
Primary result$200.00

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

F.A.Q.

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

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: 2c5c3aaf8971

What changed (latest)

v1.0.0 • 2025-11-04 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 4, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-04 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 53d55761432f