# Stair Calculator Metric

The **Stair Calculator Metric** is the *Metric* version of **mycarpentry.com's** *Imperial (inches)* Stair Calculator, and is used for calculating stair rise and run, stair angle, stringer length, step height, tread depth, and the number of steps required for a given run of stairs, but displays the results in millimeters. For convenience and flexibility, this *metric stair stringer calculator* comes in two forms, ** automatic** and

*. Click on the [?] icons to determine the best calculator to use for your stairs.*

**manual**## Looking for the *Imperial* (inches) version of the Stair Calculator?

## Looking for the *Imperial* (inches) version of the Stair Calculator?

## Looking for the *Imperial* (inches) version of the Stair Calculator?

## Metric Stair Calculator Results and related Building Codes**

The information below explains the stair calculator results in more detail and provides related **building code information. If you have any questions, please Contact Us.

**Stringer** - The *stringer* is the structural part of a set of stairs. They are cut from 2x12s or larger material - the uncut portion of the stringer should not be less than 127 millimeters (5 inches). In a set of stairs, 915 millimeters (36 inches) wide, there are typically three stringers (one stringer on each side and one in the middle). The *stringer length* is the tip-to-tip length of the cut stringer. It is used to determine the length of 2x12 material required to layout a stair stringer.

**Total Rise [A]** - The *total rise* of a set of stairs is the vertical distance between the bottom of the first step and the top of the finished landing. The *Total Rise* should be not larger than 3835 millimeters (151 inches) between landings or floor levels.

**Total Run [G]** - The *Total Run* is the horizontal length of a stair stringer. It is equal to the number of treads multiplied by the typical *Tread Depth [B].*

**Risers** - the *Step Height [F]* is the typical height of each step. Code states that this should not be greater than 194 millimeters (7 3/4 inches). In a given run of stairs, the greatest *step height* and the smallest should not exceed 9.5 millimeters (3/8 inch). Open risers with openings more then 762 millimeters (30 inches) vertical to the floor should not permit the passage of a 102 millimeter diameter (4 inches) sphere.

**Height of First Step [E]** - The the actual finished height of the first step is the same as the *Typical Step Height [F]*, but when you cut the stair stringer, the *First Step Height [E]* is always the *Step Height [F]* minus the *Tread Thickness [C]*.

**Treads** - the *Tread Depth [B]* should not be less than 254 millimeters (10 inches). In a given run of stairs, the greatest *tread depth* should not exceed the smallest by more than 9.5 millimeters (3/8 inches). Typically, a single 2x12 or two 2x6s are used for stair tread material.

**Number of Steps (Risers)** - The number of risers is not necessarily the same as the number of *Steps on Stringer [D]*. If the *Stinger Mount Type* is *Flush*, then the number of risers is the same as the number of steps. If the *Stringer Mount Type* is *Standard*, the number of risers will be one more than the number of *Steps on Stringer [D]*.

**Stringer Position [H]** - The *stringer position* refers to how far below the finished height of the upper landing the stringer will be attached.

**Headroom** - the *headroom* should not be less than 2032 millimeters (6 feet, 8 inches), measured vertically from the stair tread nosing to the nearest ceiling object.

**Stair/Rail Angle** - the angle is most useful for determining the bevel cut on a stair rail post. It can also be useful for cutting the angle on the top of the stair rail pickets.

**Stringer Length** - the *stringer length* calculation is the minimum length of 2x12 material that is required to layout and cut the stringer.

**Stairs and Landings** - *Landings* are used to break up runs of stairs. Building code states that the minimum width of a landing should not be less than the width of the flight of stairs that is served. **"Where the stairway has a straight run, the depth in the direction of travel shall be not less than 914 millimeters (36 inches)." For additional information check out Stairs with Landings.

** Note: Building Code information was obtained from the 2021 International Residential Code for One- and Two-Family Dwellings - Section 311 - MEANS OF EGRESS.

**Click here for
more information on cutting stringers and general stair building**.

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