Build a spread heatmap with a spreadsheet and a free afternoon
Posted: Tue Oct 27, 2026 6:42 am
No fancy software needed. Log the spread of one pair once per minute for two weeks, either with a small script or the platform's own tools. Dump the numbers into a sheet, add a column for hour of day in UTC and one for day of week, then build a pivot table with hours down the side and days across the top, showing the median spread in each cell.
Colour the cells from green to red and the pattern leaps out. Rollover shows up as a hot stripe. Friday afternoons turn orange. The London open usually cools off quickly. Some brokers show odd hot spots at times that match nothing in the news calendar, which is worth a polite question to support.
Two refinements make it more useful. First, use the 90th percentile as well as the median, since the median hides the ugly spikes. Second, repeat the exercise every quarter, because spread behaviour drifts as brokers change providers and as market conditions change.
A bonus step if the data allows it: split the map by account type or server. Some brokers run noticeably different pricing on standard and raw accounts, and the difference only shows when the two heatmaps sit side by side.
Once the map exists, strategy windows can be chosen with evidence, not folklore. Is there a hot spot on the current broker's map that nobody expected, and what turned out to be behind it?
Colour the cells from green to red and the pattern leaps out. Rollover shows up as a hot stripe. Friday afternoons turn orange. The London open usually cools off quickly. Some brokers show odd hot spots at times that match nothing in the news calendar, which is worth a polite question to support.
Two refinements make it more useful. First, use the 90th percentile as well as the median, since the median hides the ugly spikes. Second, repeat the exercise every quarter, because spread behaviour drifts as brokers change providers and as market conditions change.
A bonus step if the data allows it: split the map by account type or server. Some brokers run noticeably different pricing on standard and raw accounts, and the difference only shows when the two heatmaps sit side by side.
Once the map exists, strategy windows can be chosen with evidence, not folklore. Is there a hot spot on the current broker's map that nobody expected, and what turned out to be behind it?