For residential decks and stairs, the railing height is usually required to be at least 36 inches, measured vertically from the deck surface. On stairs, handrails should be between 34 and 38 inches above the nosing of the treads. Please refer to your local code for specific requirements in your area. You can also find more information here https://www.colorguardrailing.com/do-i-need-a-deck-rail/.
