Deck Stairs Calculator
Enter your total rise and we will work out the number of steps, riser height, tread depth, total run and stringer length — checked against standard code.
Estimates only. Based on standard residential code (riser 4–7.75 in, tread 10 in or more). Local code, landings, railings and stair angle can change the design. We build every stair to code on your project.
Get a Free Stair QuoteHow to Use the Deck Stairs Calculator
Measure the total rise — the straight vertical distance from the top of your deck surface down to the ground or landing — and enter it. Set your target riser height, tread depth and stair width. The calculator returns the number of steps, the exact riser height, total run, stringer length and the materials you need, and flags whether the design meets standard code.
Deck Stair Code in San Diego
San Diego follows California and IRC stair rules: risers between 4 and 7.75 inches, treads at least 10 inches deep, and a minimum 36-inch stair width. A few more requirements shape a safe, legal stair:
- All risers and all treads on a flight must be uniform — within 3/8 inch of each other.
- Stairs with four or more risers need a graspable handrail 34 to 38 inches high.
- Open sides need a guard, and stairs often need a solid landing top and bottom.
- Most exterior stairs attached to a permitted deck are covered under the deck permit.
We build every stair on a new deck or stair project to these numbers and pass inspection for you.
Rise, Run and Stringer Explained
Rise is the total height you are climbing. Divide it by a comfortable riser height (around 7 inches) and round to a whole number to get your step count. Riser height is then the total rise divided by that step count, so every step is equal. Run is the horizontal distance the stairs travel — the number of treads times the tread depth. The stringer is the diagonal board that carries the steps; its length is the hypotenuse of the rise and run. Standard 36-inch-wide stairs use three stringers; wider stairs need four or more so the treads never flex underfoot.
Frequently Asked Questions
What is the maximum riser height for deck stairs?
Code caps risers at 7.75 inches and sets a 4-inch minimum, and every riser on a flight must be within 3/8 inch of the others.
How many stringers do deck stairs need?
A standard 36-inch-wide stair uses three stringers. Wider stairs need four or more so the treads never flex underfoot.
Do deck stairs need a permit in San Diego?
Yes, when they are part of a deck that requires a permit. Stairs attached to a permitted deck are covered under that permit.
What is a comfortable stair?
A riser near 7 inches with an 11-inch tread feels natural to most people and keeps the climb safe and even.