Measuring Historical Bid-Ask Spreads and Their Trading Costs in MetaTrader 5
Summary
The article explains how bid and ask prices affect market-order entries and exits, then presents a MetaTrader 5 indicator approach for measuring historical spreads from tick data. It compares observed average spreads with broker-declared levels and normalizes spread values against a reference EURUSD spread so that different currency pairs can be compared in a common display. The implementation gathers bid and ask changes within each chart bar and plots actual and declared spread series.
Examples discuss how wider spreads can consume a larger share of a trade’s risk when stop and target distances are small, and how spreads may widen during volatile periods, late sessions, or weekends. The author uses these observations to argue for comparing execution costs across brokers and instruments before trading.
The examples are broker- and period-specific rather than universal. The normalization method is designed for forex and is explicitly not tested on non-forex instruments; tick availability also limits the process to MetaTrader 5.
Key ideas
- Market buys execute at the ask and market sells at the bid, so spread affects both entry and exit costs.
- Tick data can be used to estimate historical average spreads and compare them with declared spreads.
- Normalizing spread levels against a reference currency pair helps compare pairs with different price scales.
- A fixed spread cost consumes a larger fraction of risk when stop and target distances are small.
- The article’s examples are broker-specific, and the proposed normalization is not validated for non-forex instruments.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.