CHART CHOICES & CHECKABLE METHODS

Logarithmic scale graph: equal ratios instead of equal differences

On a logarithmic axis, equal distances represent equal ratios. On a linear axis, equal distances represent equal differences. Ordinary real-valued log scales require positive values; zero and negative observations cannot be placed on them directly.

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The comparison at a glance

Original valuelog10(value)Ratio from previous
10
10110
100210
1000310

Compare a simple four-value sequence

The fictional values 1, 10, 100 and 1,000 have base-10 logarithms 0, 1, 2 and 3. They are equally spaced on a log axis because each value is ten times the previous one. On a linear axis their successive gaps are 9, 90 and 900, making the largest increase visually dominate.

Read the question implied by distance

A move from 2 to 4 and a move from 20 to 40 both double the value. They span the same log distance but different linear distances. A logarithmic view can help compare multiplicative growth across very different levels. A linear view is more direct when absolute changes are the decision measure.

Do not hide incompatible observations

The logarithm of zero is not finite, and negative values do not have an ordinary real logarithm. Dropping such rows or adding a constant changes the dataset or transformation. If an alternative transformation is used, name it and explain how values near zero behave. A log axis is not a cosmetic setting that applies meaningfully to every list.

Current tool support and a safe next step

ChartsAI’s interactive makers currently use linear numeric axes; this guide does not claim a log-axis control exists. The table supplies the exact transformation for this worked sequence. If plotting transformed values in a linear maker, label the axis log10(value) and retain the original values separately. That produces transformed coordinates, not automatically an axis with original-value tick labels.

A related chart you can inspect

Positive correlation scatter plot with a fitted line
Positive correlation scatter plot with a fitted line. Original fictional data; this linked example has its own complete input and calculation settings.

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References and reproducibility

The worked arithmetic and teaching examples on this page are original. Background reading: ONS guidance on axes. Source code and reuse terms expose the implemented calculations.

Written by SupaMakers for ChartsAI · September 8, 2026.

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