# Step Tread and Rise Dimensions

Next we will see the minimum measurements and step tread and rise standard dimensions for a staircase.

You will be able to use a step tread and rise calculator. Read to the end…

## Standard Stair Rise and Run for Interior Staircase

The measurements of the step tread and rise of an interior staircase may vary, according to local regulations.

As a general rule, it is established that 2 treads + 1 rise = 62-65 cm (25 – 26 inches). This rule should serve as a guide for the calculation of stairs.

### How Long is the Step of a Stair?

The step size of a staircase can vary from one country to another, although there is a range of measurements accepted in most regulations.

#### Standard Stair Width

The minimum width that the flight of an interior staircase in a home must have is 80 cm (32”). This value is accepted for most countries. While standard stair width should be about 40 inches.

#### Minimum Stair Width

For stairs of unrestricted use (stairs to the basement, for example) the width of the step can be from 50 to 60 cm wide (20 to 24 inches).

### Standard Step Height and Depth

#### Stair Tread Measurements

The footprint of the stairs for an interior housing space must be at least 25 cm (10 inches), with 28 cm (11”) being a standard measurement for most countries.

The stair footprint measurement that produces the greatest comfort both going up and down is 30 to 31 cm (12”), although it has the drawback of requiring a larger area to develop the flights of a staircase.

For commercial spaces, the step of the stairs must have a minimum of 28cm (11”) and in spaces with a large influx of people, such as schools, health centers, theaters, etc. the tread should be 30cm (12 inches).

### How long is the Rise of a Stair?

First let’s clarify what is the riser of a staircase.

#### What is the Rise of a Staircase?

The rise of a staircase is the vertical part of the rung.

Sometimes, it is required to make the rise inclined, in order to reduce the length of the staircase, without reducing the treads.

All the rise of the same staircase must have the same measurement, although slight variations of up to 5% are accepted.

### Standard Dimensions of the Rise for a Staircase

The rise of a staircase must measure a maximum of 20 cm (8 inches) and a minimum of 15 cm (6 inches), with 17 to 18 cm (7 inches) being the measurements most used by architects when designing an interior staircase for a home.

#### Maximum Stair Riser Height

The maximum stair riser height should not be more than 18cm (7 inches). Although, 20cm (8 inches) are used in tiny home designs.

In the case of curved or SPIRAL stairs, the  curved steps must  be at least 44 cm (17”) on their widest side and 5 cm (2”) on the narrowest.

##### If the Measure of a Rise is 7 inches, How much is the Tread ?

If the measurement of a rise is 17.5 cm (7 inches), the tread of the staircase would be 29 cm (11.5”). These pitch and rise measurements are optimal.

However, it should be said that they can vary slightly and would also be suitable measurements for the treads and risers of the stairs.

If you want to know WHERE TO PUT the stairs in a small house, you can click on the blue link.

#### How many Steps does the Staircase Have?

A staircase should not have more than 16 to 18 steps in a row, on the same branch.

In the case of “U” or “L” shaped stairs, the flights should not have more than 16 consecutive steps, that is, without a landing. Landing should not measure less than 1 tread x 3 times.

## Stair Tread and Rise Calculation for 1 Flight Staircase

### Other Measurements of a Staircase

In circulation areas, 1 isolated step or two consecutive steps should not be installed. That is, there must be at least 3 steps for each staircase.

The angle formed between the tread and the riser is generally 90 degrees, and can vary up to 75 degrees.

The inclination or slope of the staircase will be defined by the ratio of 2 treads + 1 riser = 62-65 cm (25 inches).

Of course, the measures that we calculate for the tread and the rise will define the slope of the stair.

The thickness of a concrete stair (stair ramp) should be at least 100mm (4 inches) and up to 200mm (8 inches) thick.

The height of free passage on a stairway must be from 2.0 to 2.20 meters (80 inches height), thus guaranteeing safety and spatial comfort.

All these are recommendations, they guarantee an adequate stairway design, with maximum levels of functionality and comfort, being easily and safely accessible for all age ranges.

If you want to see various designs of STAIRS, you can follow this link.

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