The height of a set of stringers (also known as stair stringers) depends on the total rise that the stairs need to cover, the height of each individual step (riser height), and the number of steps in the stringer. Assuming a common riser height of 7.5 inches (19.05 cm) per step, here are the heights for stringers with different numbers of steps. For example:- For a 4-step stringer: Height = 4 steps × 7.5 inches/step = 30 inches.

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 5 inches (127 mm). In a set of stairs 36 inches wide, there are typically three stringers (one on each end and one in the middle).

Most steps (treads + rise) have a height, or “rise,” of about 7 to 7.5 inches (18–19 cm). There is chance to feel difficult to climb in taller steps while shorter steps make ascending and descending feel awkward and may present a tripping hazard. The height of each stair or stringer has to be enough for a person to safely and smoothly walk up.

As you know that number of steps is equal to number of treads on stringer. To calculate total height of your stair multiply number of riser by one riser height. To figure out number of riser, add 1 in number of steps. Estimated riser height should be 7 inches.

Stringer risers are the vertical section of an individual stair and treads are horizontal section. Riser have a maximum height of 7 3/4 inches. The international residential code (IRC) does not set a minimum height, but other codes, such as the International Building Code (IBC), set a minimum riser height of 4 inches.

The height of the stair must be consistent, and the risers cannot vary more than 3/8 inch on a staircase. The nosing, or horizontal overhang of a stair should be a minimum of 3/4 inch and a maximum of 1 1/4 inch. Nosings are not required but make stairs safer. The depth of tread of stair with nosing must be a minimum of 10 inches. If the stair do not have a nosing or overhang, the tread has a requirement of 11 inches minimum.

Residential stair are required to have a minimum width of no less than 36 inches and should have stringers every 16-18 inches. Stairways of 36 inches will need at least three stringers. Stairways wider than 36 inches will need at least four stringers.

To calculate total rise of stair multiply number of steps (riser) by one riser height. The total rise of a flight of stairs is the vertical rise between the bottom of the first step and the top of the finished landing. The vertical rise should be not greater than 151 inches (3835 mm) between landings or floor levels.

To calculate total run multiply number of treads by tread depth. 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.

Height of First Step:- The the actual finished height of the first step is the same as the Typical Step Height, but when you cut the stair stringer, the First Step Height is always the Step Height minus the Tread Thickness. So, first step height should be 5-1/2″.

**How tall is a 4, 2, 3, 5, 6, 7, 10 & 14 step stringer**

Length of stringer is calculated by using Pythagoras formula of right angle traingle. Hypotenuse of right angle triangle gives your length of stringer. So, square root of sum of square of rise and run gives Hypotenuse.

If your stringer have 2 steps, it means there is two riser and 2 treads, first riser height should be 5-1/2″ and 2nd riser height is 7 inches, so total rise = 7″+ 5-1/2″ = 12.5″. To calculate total run multiply no. of treads (steps on stringer) by 10.5″ , total run = 10.5″×2 = 21″. Take the square root of sum of square of total rise and run which yields length of stringer. Length of a 2 step stringer = √ (12.5″)^2 + (21″)^2 = 24.44″ or 24-7/16″.

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**How tall is a 4 step stringer**

A 4 step stair’s stringer (4 riser & 4 treads) should be 49.66″ or 49-11/16″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 3×7″ (for next 3 riser height) = 5-1/2″ + 21″ = 26.5″. Total run = 4× 10.5″ = 42″. Length of a 4 step stringer = √ (26.5″)^2 + (42″)^2 = 49.66″ or 49-11/16″.

The typical deck height of a 4 step stair’s stringer should be approximately 26.5 inches (2.2 feet). This includes the height of the first riser (5 1/2 inches) plus the height of the next three risers (7 inches × 3 = 21 inches), so total height of 4 step stringer = 21 inches + 5 1/2 inches = 26.5 inches.

A typical 4 step stringer has a dimensions is (L × W × H): 49 11/16″ × 26 1/2″ × 42″ in which 49 11/16 inches is the length of stair’s stringer, 26 1/2 inches is the height (total rise) of stair and 42 inches is the width (total run) of stair.

**How tall is a 2 step stringer**

A 2 step stair’s stringer (2 riser & 2 treads) should be 24.44″ or 24-7/16″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 1×7″ (for next 1 riser height) = 5-1/2″ + 7″ = 12.5″. Total run = 2× 10.5″ = 21″. Length of a 2 step stringer = √ (12.5″)^2 + (21″)^2 = 24.44″ or 24-7/16″.

The typical deck height of a 2 step stair’s stringer should be approximately 12.5 inches (1.04 feet). This includes the height of the first riser (5 1/2 inches) plus the height of the next one riser (7 inches × 1 = 7 inches), so total height of 2 step stringer = 7 inches + 5 1/2 inches = 12.5 inches.

A typical 2 step stringer has a dimensions is (L × W × H): 24 7/16″ × 21″ × 12 1/2″ in which 24 7/16 inches is the length of stair’s stringer, 12 1/2 inches is the height (total rise) of stair and 21 inches is the width (total run) of stair.

**How tall is a 3 step stringer**

A 3 step stair’s stringer (3 riser & 3 treads) should be 37.05″ or 37-1/16″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 2×7″ (for next 2 riser height) = 5-1/2″ + 14″ = 19.5″. Total run = 3× 10.5″ = 31.5″. Length of a 3 step stringer = √ (19.5″)^2 + (31.5″)^2 = 37.05″ or 37-1/16″.

**How tall is a 5 step stringer**

A 5 step stair’s stringer (5 riser & 5 treads) should be 62.28″ or 62-1/4″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 4×7″ (for next 4 riser height) = 5-1/2″ + 28″ = 33.5″. Total run = 5× 10.5″ = 52.5″. Length of a 5 step stringer = √ (33.5″)^2 + (52.5″)^2 = 62.28″ or 62-1/4″.

**How tall is a 6 step stringer**

A 6 step stair’s stringer (6 riser & 6 treads) should be 74.28″ or 74-7/8″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 5×7″ (for next 5 riser height) = 5-1/2″ + 35″ = 40.5″. Total run = 6× 10.5″ = 63″. Length of a 6 step stringer = √ (40.5″)^2 + (63″)^2 = 74.28″ or 74-7/8″.

**How tall is a 7 step stringer**

A 7 step stair’s stringer (7 riser & 7 treads) should be 87.51″ or 87-1/2″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 6×7″ (for next 6 riser height) = 5-1/2″ + 42″ = 47.5″. Total run = 7× 10.5″ = 73.5″. Length of a 4 step stringer = √ (47.5″)^2 + (73.5″)^2 = 87.51″ or 87-1/2″.

**How tall is a 8 step stringer**

A 8 step stair’s stringer (8 riser & 8 treads) should be 100.13″ or 100-1/8″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 7×7″ (for next 7 riser height) = 5-1/2″ + 49″ = 54.5″. Total run = 8× 10.5″ = 84″. Length of a 8 step stringer = √ (54.5″)^2 + (84″)^2 = 100.13″ or 100-1/8″.

**How tall is a 9 step stringer**

A 9 step stair’s stringer (9 riser & 9 treads) should be 112.74″ or 112-6/8″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 8×7″ (for next 8 riser height) = 5-1/2″ + 56″ = 61.5″. Total run = 9× 10.5″ = 94.5″. Length of a 9 step stringer = √ (61.5″)^2 + (94.5″)^2 = 112.74″ or 112-6/8″.

**How tall is a 10 step stringer**

A 4 step stair’s stringer (4 riser & 4 treads) should be 125.37″ or 125-3/8″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 9×7″ (for next 9 riser height) = 5-1/2″ + 63″ = 68.5″. Total run = 10× 10.5″ = 105″. Length of a 10 step stringer = √ (68.5″)^2 + (105″)^2 = 125.37″ or 125-3/8″.

**How tall is a 12 step stringer**

A 12 step stair’s stringer (12 riser & 12 treads) should be 150.61″ or 150-5/8″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 11×7″ (for next 11 riser height) = 5-1/2″ + 77″ = 82.5″. Total run = 12× 10.5″ = 126″. Length of a 12 step stringer = √ (82.5″)^2 + (126″)^2 = 150.61″ or 150-5/8″.

**How tall is a 14 step stringer**

A 14 step stair’s stringer (14 riser & 14 treads) should be 175.84″ or 175-13/16″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board. Total rise = 5-1/2″ (for 1st riser height) + 13×7″ (for next 13 riser height) = 5-1/2″ + 91″ = 96.5″. Total run = 14× 10.5″ = 147″. Length of a 14 step stringer = √ (96.5″)^2 + (147″)^2 = 175.84″ or 175-13/16″.

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**Conclusions:**

A 4 step stair’s stringer (4 riser & 4 treads) should be 49.66″ or 49-11/16″ long (tall) when you are using each tread depth of 10.5″ and riser height of 7 inches with 2×12 board.