The calculators on calculator.net, blocklayer.com, and mycarpentry.com are some examples of online stair calculators. The stair calculator on calculator.net is the simplest one, requiring only two dimensions of the stairs: the rise and the run. The other two calculators allow the user to include other dimensions in the calculation.
The blocklayer.com offers other practical possibilities, such as converting the calculator into metric measures or calculating the dimensions of a spiral staircase.
Follow safety guidelines for stair measurements while designing a staircase. Stairs compliant with these rules have enough foot space and headroom and are less likely to cause tripping. These guidelines are available under the stair calculator on calculator.net.