225/45R13 in inches

A 225/45R13 tire is 21.0″ tall and 8.9″ wide, and fits a 13″ wheel. In inches it is written 21.0×8.9R13.

Diameter20.97″

Width8.86″

Sidewall3.99″

Drawn to scale. Nominal dimensions calculated from the size code.

Manufacturer data

How tall 225/45R13 tires really are

Heights published by Toyo for the one tire in this size. Their published revolutions per mile work out to 20.3″ under load (below).

The one tire listed, the Toyo Proxes R888R, measures 20.94″: 0.03″ shorter than the size code's 20.97″.

Height under load20.3″

Published revs per mile (992) mean the tire rolls like a 20.3″ tire on the vehicle. Use this for speedometer calibration.

1 tire in 225/45R13

Sort by the spec you care about.

	Load					Revs/mi	Source
Toyo Proxes R888RPerformance	SL · 84V	20.94	18.5	6.3	1,102	992	Spec page

Is 225/45R13 a 21-inch tire?

≈21″

Yes. The size code works out to 20.97″, and the 1 tire here publishes 20.94″, so people call it a 21.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 225/45R13	Difference
185/60R13	21.74	+0.77″	+3.7%
175/70R13	22.65	+1.67″	+8.0%
205/60R13	22.69	+1.71″	+8.2%
185/60R14	22.74	+1.77″	+8.4%
175/65R14	22.96	+1.98″	+9.5%
195/60R14	23.21	+2.24″	+10.7%
185/65R14	23.47	+2.50″	+11.9%

How to read 225/45R13

How to read any tire size

How 225/45R13 84V is printed on the sidewall. It's the most common code among the 1 tire here; tires in this size come in other load and speed ratings too.

1225Section width

225 mm across the widest point, or 8.86 inches. Every 225 size

245Aspect ratio

A percentage, not a measurement: the sidewall is 45% as tall as the tire is wide, which is 101.3 mm or 3.99 inches.

3RConstruction

Radial construction.

413Wheel diameter

Mounts on a 13-inch wheel. Approved wheel widths run 7.0″ to 8.5″.

584Load index

Each tire carries up to 1,102 lb (500 kg) at its maximum pressure.

6VSpeed rating

Rated for up to 149 mph sustained.

Specification	Inches	Metric
Overall diameter	20.97	533 mm
Section width	8.86	225 mm
Sidewall height	3.99	101.3 mm
Circumference	65.9	1,674 mm
Revolutions per mile (calculated, unloaded)	961.6	598 per km
Revolutions per mile (published by manufacturers)	992	616 per km
Approved wheel width	7.0–8.5	178–216 mm

Speedometer error after switching to 225/45R13

Your actual speed– mph

Questions about 225/45R13

What is 225/45R13 in inches?

20.97 inches tall, 8.86 inches wide, on a 13-inch wheel. Written in inches, that is roughly 21.0×8.9R13.

What wheel width do I need for 225/45R13?

Manufacturers approve 7.0–8.5″ wide wheels for this size.

How many revolutions per mile does a 225/45R13 make?

Published figures run 992 revolutions per mile. The calculated figure is 961.6, but manufacturers measure the tire under load, where it rolls on a smaller radius.