What is a worked example of scalping spreads?
A “worked example of scalping spreads” is a step-by-step numerical scenario that shows how the bid–ask spread and related trading costs can dominate results when trades are held briefly. The goal is not to predict a profit, but to make the cost mechanics concrete so you can verify each calculation under your own assumptions.
In forex, the spread is the difference between the ask price (buy) and the bid price (sell). When you trade for a short time horizon, you effectively need price movement that covers the spread plus other costs, because the moment you enter, you start “on the wrong side” of the transaction cost.
How does a worked example of scalping spreads work?
Below is one transparent scenario. It uses simplified mechanics so you can check every number.
Assumptions (state everything)
- You trade a single forex position with a chosen lot size.
- The spread is constant during the trade. (In real conditions, it can widen or move.)
- You pay the spread plus a separately stated commission cost per lot.
- Currency conversion effects are ignored (or assumed already included in the “value per pip” figure).
- Price movement is measured in pips, and the pip value per lot is known.
Define the cost per trade
Let:
- Spread = 0.2 pips (example input)
- Commission = $3 per lot (example input)
- Lot size = 1.0 lot (example input)
- Pip value = $10 per pip per lot (example input)
If you buy at the ask and later sell at the bid, the spread effectively costs you the spread amount in pips. So the spread cost in dollars is:
- Spread cost = (Spread in pips) × (pip value)
- Spread cost = 0.2 × $10 = $2
Add commission:
- Total trading cost = $2 + $3 = $5 per trade
Compare cost to a small price move
Now assume the market moves in your favor after entry.
- Assumed favorable move = 0.6 pips (example input)
Gross movement value (before costs) is:
- Gross = 0.6 × $10 = $6
Net result estimate (before any other slippage or fees) is:
- Net ≈ Gross − Total trading cost
- Net ≈ $6 − $5 = $1
This is the core “scalping spreads” idea: with short holds, the spread and costs can be a large fraction of the total move.
Same mechanics, different spread (compare both outcomes)
Keep everything the same, but change only the spread.
Case B:
- Spread = 0.6 pips (example input)
- Commission = $3 per lot
- Pip value = $10 per pip
- Favorable move = 0.6 pips
Spread cost:
- 0.6 × $10 = $6 Total cost:
- $6 + $3 = $9 Net:
- Net ≈ $6 − $9 = −$3
Same favorable 0.6-pip move, but a wider spread makes the trade result negative. That is why “scalping spreads” is often discussed as a cost sensitivity problem rather than a forecasting problem.
Relevant limitations and risks
A worked example is only as reliable as its assumptions. Common failure modes include:
1) Spread is not constant
In live trading, spreads can widen around volatile moments or when liquidity thins. If your example assumes a 0.2-pip spread but the realized spread is 0.6 pips, the cost changes materially, as shown in the comparison.
2) Execution effects (slippage)
If the trade fills at a different price than expected, the realized pip movement differs from your assumption. Even a few tenths of a pip can be comparable to the spread in a scalping-style horizon.
3) Costs differ by venue and account setup
Commission schemes, minimum fees, and other charges can differ. If your model omits a fee type or uses the wrong per-lot value, net calculations will not match reality.
4) Measurement and pip value assumptions
Pip definitions and pip value depend on the instrument and lot specification, and pip value may change with currency effects. If you use an incorrect pip value, the conversion from pips to dollars will be wrong.
5) Historical intuition is not evidence
Even if a spread-cost relationship held in the past, it does not guarantee it will hold in the future. You can treat a worked example as a calculation template, not as an outcome predictor.