Quick answer

Rise + run -> slope % and angle. Angle + run -> rise and slope %.

Formula

  • Slope % = (rise / run) x 100
  • rise = run x tan(angle)
  • Angle = arctan(rise / run)

Introduction

The Slope Percentage Calculator lives in the lab panel at the top of the home page. It runs entirely in your browser, which matters when cell service is weak at a job site.

Read what slope percentage means if the labels are new, then keep how to calculate slope percentage nearby for manual verification.

This article explains input modes, result fields, and how to avoid fighting the tool when measurements change mid-conversation.

Tool overview

Three inputs share one triangle: rise (vertical change), run (horizontal distance), and angle in degrees. Two output readouts show slope percent and angle even when you drive the math from rise and run.

Rise-and-run mode is default. Type both and the tool fills angle and percent. Clear a field to reset that value; hyphens appear until enough information exists.

Angle mode activates when you edit the angle field after run is present. The tool holds run steady and recalculates rise using tangent. That mirrors how roof and ramp checks often start from a target angle.

Grade conversion examples on the home page below the hero show roads, roofs, and ramps you can replicate in the panel for practice.

Formula and relationships

  • Input rise and run
  • Read slope % and angle
  • Edit angle with run set to update rise

Use the same units in rise and run. The tool does not convert feet to meters for you.

For formula background see slope percentage formula; for batch projects see slope percentage in Excel.

Step-by-step guide

  1. Open the home page panel. Scroll to the lab worksheet if you arrived from an article.
  2. Enter rise and run. Watch percent and angle update.
  3. Switch to angle mode. Enter run, then change angle to solve rise.
  4. Compare with a sketch. Confirm sign and direction on paper.
  5. Screenshot or write results. Include units in your field notes.

Ramp check example

Run 360 in, rise 30 in: percent = 8.33%, angle about 4.76 degrees. Many accessibility tables reference slopes near 8.33% for new ramps; verify your local code.

See ramp context inside slope percentage examples and degree comparisons in slope percentage vs degrees.