Timeframes, Log Scales and Misleading Charts

The same asset can look completely different on two charts. The reason is usually two choices: the timeframe and the scale of the price axis. Understanding both helps you see a chart as it is, rather than as its settings make it look.

What a timeframe is

The timeframe is the length of time each candle covers. On a 15-minute chart each candle is 15 minutes; on a daily chart each candle is one full day. Short timeframes contain more detail and more noise; long timeframes give a calmer, broader picture.

The important point is that the trend can differ between timeframes. EUR/USD might be falling on the weekly chart, bouncing on the daily chart and flat on the hourly chart. None of these is wrong. Many traders use a multi-timeframe approach: they take the overall direction from a higher timeframe and look for entry timing on a lower one.

Linear versus logarithmic scale

On a linear scale, equal vertical distance means an equal change in price. The move from $10 to $20 takes the same space as the move from $100 to $110. On a logarithmic scale, equal vertical distance means an equal percentage change. A move from 10 to 20 (a 100% gain) takes the same space as a move from 100 to 200.

Price move	Dollar change	Percentage change
10 to 20	$10	100%
100 to 110	$10	10%

For assets that have multiplied many times over the years, such as Bitcoin, a linear scale makes the early moves look almost flat and recent moves look enormous. A log scale gives a fairer picture of relative growth. Over short periods, or for assets with limited swings like most major forex pairs, the difference between the two scales is small.

Why a chart can mislead

• Stretching the price axis can make a small wobble look like a crash or a surge.
• A carefully chosen date range can appear to "prove" almost any story.
• A trendline that fits on a linear scale may sit somewhere else on a log scale.

Before drawing a conclusion, check which timeframe and scale you are looking at, and zoom in and out a few times. If an idea only holds on one carefully chosen view, treat it with suspicion.

Key takeaways

• The timeframe sets how much time each candle summarises.
• Trends can differ across timeframes and all be correct.
• A log scale shows equal percentage moves as equal distances, which suits large long-term moves.
• Check the chart settings before trusting any reading.