Compare Fonts → Sans Serif → Roboto vs Fira Sans

Roboto vs Fira Sans

Both are sans serif faces on Google Fonts. Roboto has the larger x-height, so it looks bigger at the same size. Fira Sans takes more horizontal space.

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Roboto

Handgloves & Quartz Jockeys

The quick brown fox jumps over the lazy dog. Pack my box with five dozen liquor jugs, then ship it to 1,842 Grove Street by 9:30 AM.

Fira Sans

Handgloves & Quartz Jockeys

The quick brown fox jumps over the lazy dog. Pack my box with five dozen liquor jugs, then ship it to 1,842 Grove Street by 9:30 AM.

Measured differences

Measured from the font files. Heights and widths are shown as a share of the font size, so they compare directly at any point size.
Measurement	Roboto	Fira Sans	Difference
x-heightHeight of lowercase letters, as a share of the font size. Higher reads larger at the same point size.	52.8%	52.7%	0.1%
Cap heightHeight of capitals, as a share of the font size.	71.1%	68.9%	2.2%
x-height to cap ratioProportion of lowercase to uppercase. Higher feels more modern and open.	0.74	0.77	0.02
Stroke weightMeasured thickness of a vertical stroke. Higher is heavier on the page.	9.1%	9.9%	0.8%
Stroke contrastHorizontal stroke divided by vertical. 1.0 is even; below 0.5 means strong thick-thin modulation.	0.82	0.75	0.07
Average character widthMean lowercase advance. Higher takes more horizontal space.	49.9%	50.8%	0.9%

Where they diverge most

Stroke contrast: Roboto measures 0.82, Fira Sans measures 0.75. Horizontal stroke divided by vertical. 1.0 is even; below 0.5 means strong thick-thin modulation.
Stroke weight: Roboto measures 9.1%, Fira Sans measures 9.9%. Measured thickness of a vertical stroke. Higher is heavier on the page.
Average character width: Roboto measures 49.9%, Fira Sans measures 50.8%. Mean lowercase advance. Higher takes more horizontal space.

At a glance

	Roboto	Fira Sans
Category	Sans Serif	Sans Serif
Weights	9	9
Variable axes	2	None
Language subsets	9	7
Designer	Christian Robertson	Carrois Apostrophe