Tyre Size Calculator - Calculates Tyre Dimensions for Plus Sizing

Find the perfect tire size for your larger wheels with our Tire Size Calculator (Tire Plus Sizing Calculator) while keeping proper car performance, handling, and a comfortable ride. Don't let a tire mismatch ruin your car's sleek new look. This tool calculates the dimensions of the tire for plus sizing or upsizing. Simply enter your current tire size and the size of your new wheels, and our versatile tool will recommend several tire options for your car.

Benefits of using our calculator:

  • Find the perfect tire size for your upsized wheels.
  • Maintain the overall diameter and circumference of your tires.
  • Avoid potential issues such as rubbing and speedometer errors.
  • Find your original tire specifications: rim diameter, tire diameter, tire width and tire sidewall height, based on the tire size designation, e.g. "P225/60R16".
  • Find out the speedometer error for your new tires.

Here's how it works:

  • Select your current tire size (OE or stock): This can be found on the sidewall of your existing tire, usually in a format like "P225/60R16."
  • Select your desired new wheel diameter: This is the size of the new wheel you're planning to install, measured in inches.
  • Click the button "Show optional tires…": We'll instantly generate a list of compatible tires that maintain the overall diameter and circumference of your original setup.

The most commonly used Plus Sizing techniques are Plus One, Plus Two, and Plus Three. All of these methods involve using a wheel with a larger diameter than the original wheel, with the diameter being one, two, or three inches larger. Each of these upsizing methods requires a larger replacement wheel or rim, which affects the tire choice not only because of the increased diameter but also because of the width of the wheel.

Tyre Dimensions

Tyre Plus Sizing Calculator

select OE tyre size

eg. 195/65R15

/ R
select new wheel diameter size


    Table columns headings:

  • The "Diff" column may contain percentages ranging from -3% to +4% (+5% for winter tires). These percentages represent the acceptable deviation of the optional tire diameter from the original tire diameter.
  • The "Winter tires only" column that has an asterisk in a table row indicates that the tire size in that row is suitable for winter tires only.

Try our other calculators:

What is Tire Plus Sizing?

Tire plus sizing or tire upsizing refers to the process of replacing a wheel with a larger one and fitting an appropriate tire onto that wheel. This tire has a smaller sidewall height (lower profile, series or aspect ratio) compared to the original equipment tire (also known as the OE or stock tire). However, the overall diameter and circumference of the new tire are kept roughly the same as those of the OE tire to maintain optimal car handling and speedometer accuracy.

Plus Sizing - Upsizing

The most popular Plus Sizing methods are:

  • The "Plus One" method uses a wheel that is one inch larger in diameter than the Original Equipment (OE) wheel. This is paired with a new tire that has a smaller sidewall height than the OE tire, specified by a lower tire Aspect Ratio (AR, also known as tire series/profile). Additionally, the plus sizing methods for tires typically involve using a wider tire (larger section width) than the original tire.
  • The "Plus Two" technique refers to the use of a wheel that is two inches greater in diameter than the original equipment wheel. This is matched with a tire that has a lower aspect ratio and a larger width than those of the OE tire.
  • In the "Plus Three" method, a three-inch larger wheel is used with a tire having a lower profile and larger width than the OE tire.

Each of these plus sizing methods requires a larger replacement wheel/rim, which affects the tire choice, not just because of its increased diameter, but also because of its width.

Tire Plus Sizing Calculator - How Does the Calculator Work?

The Tire Plus Sizing Calculator is a tool that helps you determine the ideal tire size when fitting larger wheels onto a vehicle. It computes the dimensions of the tire for plus sizing.

To use the calculator, simply input your existing tire size (original equipment - OE tire size or stock tire size) and desired new rim diameter. Then, click on the "Show Optional Tyres for the New Wheel" (orange button), and we'll provide you with a list of compatible tire options based on established industry guidelines. The list displays key information about each tire, such as the overall tire diameter, sidewall height, and the tire diameter difference between an alternate and the original tire size, allowing you to make an informed decision.

A new feature of the calculator is that you can display adequate tires for all three Plus Sizing methods (Plus One, Two, and Three) at the same time by clicking on the "Show Plus One, Two 'n Three Tyre Sizes" (blue button).

The calculator lists compatible tire sizes where the overall tire diameter and circumference are similar to the original tire, ensuring compatibility with your car's systems. The calculation is based on the entered OE tire size, where the overall tire diameter difference between an optional tire (OT) and the OE tire fits within the range of -3% to +4% (+5% for winter tires) of the difference between the overall OE tire diameter and the OE wheel diameter (OE TD - OE WD or 2 x OE tire sidewall height). This formula is used by leading tire manufacturers.

Before changing your tires, it's important to note that tire interchangeability isn't always possible. Therefore, it's recommended that you consult your car manufacturer's manual for guidance.

When practicing Plus Sizing methods and changing tires and wheels, it's crucial to pay special attention to the following factors: wheel size (diameter, width, and offset), tire construction (radial or bias-ply), tire speed rating, load capacity, and maximum inflation pressure.

Please note that the tire dimensions presented in the resulting table as possible new tire dimensions for the specific new wheel diameter you've entered aren’t all suitable for your car. The tire dimensions listed satisfy only one criterion in the quest for a new tire dimension, which is that the new tire diameter has to be in a certain range in relation to the entered tire size (which should be the OE or stock tire size) diameter.

After finding the right tire size, you need to find the appropriate wheel for the tire size. You already have one wheel dimension, the wheel diameter, but you also need to know the wheel width. The wheel width has to be suitable for the selected tire size. Every tire size has the measuring rim and the approved rim width range. You can use our Wheel/Rim Size Calculator to find the appropriate wheel for the tire size. Once you enter the chosen tire size, you'll be presented with the adequate rim width range for the tire size. The chosen wheel will determine the real tire size when the tire is fitted on the wheel. An assembly consisting of the tire and wheel has to be adequate for your car.

While everything that has been said is important, it's not enough to ensure proper tire-to-rim fitment.

Please note that the purpose of these calculators and charts isn't to give the final verdict on what is best for your needs, but only to give you a suggestion in your quest for the final answer. This area isn't as simple as it might look at first sight, and it requires careful consideration.