What is a Worked Example of Trade Logging?

Direct answer

A worked example of trade logging is a fully specified scenario that shows what gets recorded for each trade, which calculations are performed from those recorded fields, and what assumptions must be true for the numbers to be meaningful. The point is not to predict outcomes, but to make the record internally consistent so you (or someone else) can reproduce the same calculations.

Mechanism or definition

Trade logging is the systematic documentation of trade details so that you can review decisions and results later. A trade log typically includes:

• Identification: trade date/time and instrument (at a minimum).
• Intent fields: strategy notes, risk plan, or entry/exit rationale (optional, but useful).
• Execution fields: entry price, exit price, size/units, direction, and the exact timestamps.
• Costs fields: commissions, spreads (or spread estimate rules), and any fees.
• Results fields: gross result and net result after costs.

Stable mechanics are the calculation rules you apply to the log entries. Variable conditions are everything that can differ by broker, account type, or market moment: transaction costs, execution quality, and whether your recorded prices truly match fills.

A “worked” example means every input needed for the calculations is stated, and every step is shown.

Evidence or example

Assume you log one trade with the following intentionally simple fields.

Assumptions (state up front):

1. You trade a single instrument using a fixed units size. The exact instrument pricing convention is not needed for arithmetic if we treat “profit in account currency” as directly computed from price moves.
2. Entry fill price is 1.1000.
3. Exit fill price is 1.1050.
4. Position size produces a profit factor of 10 per 0.001 price movement (this is an arbitrary conversion chosen only to keep the example numeric).
5. Commission and other fees total 2.00 account currency.
6. You already used the fill prices (not quotes) so spread is not estimated separately.

Step-by-step calculations:

1. Price movement = 1.1050 − 1.1000 = 0.0050.
2. Convert movement to gross profit: 0.0050 ÷ 0.001 = 5 increments. Profit per increment = 10. Gross profit = 5 × 10 = 50.00.
3. Net profit = Gross profit − costs = 50.00 − 2.00 = 48.00.

What you would verify later:

• Your log’s gross profit should match the arithmetic above given the recorded inputs.
• Your net profit should match the same gross value minus the exact cost entries you recorded.
• If you change any assumption (for example, replace fill prices with mid-quote prices or re-estimate spread), the computed numbers will change.

Limitations and risks

Trade logging is only as reliable as the consistency and completeness of the recorded fields. Material failure modes include:

1. Missing or inconsistent cost data: If commissions, swaps/financing, or estimated spreads are omitted or double-counted, net results won’t be comparable across trades.
2. Using the wrong prices: Logging quote prices instead of execution (fill) prices can systematically bias profit calculations, especially during fast moves.
3. Unclear definitions: “Win” can mean different things (gross vs net, or filled vs planned exit). If definitions shift, summary metrics like win rate become misleading.
4. Time and market regime changes: Even accurate historical logging does not ensure future performance because market conditions, liquidity, and costs can change.

None of this is a guarantee or prediction; it is about making records auditable.

Verification or next question

To independently verify a trade log calculation, pick one trade and recompute the results from the recorded fields: confirm the input values, confirm the cost model you used, and confirm whether your gross/net definitions match your log’s summary metrics. A good next question is: “Does my log specify whether prices are fills, and do costs reflect the same rule every time?”