Ramp Slope Calculator

Plan compliant ramps using rise, run, length, or angle inputs fast units. Get slope percent, ratio checks, and downloadable reports for construction teams daily.

Enter ramp details

Choose the pair you know best.
All lengths use this unit.
Vertical height difference.
Needed for Rise + Run mode.
Used with Rise + Length or Run + Length.
Used with Rise + Angle or Run + Angle.
Used with Rise + Ratio mode.
Higher N means a gentler ramp.
Lower percent means safer walking grade.

Formula used

This calculator models a straight ramp as a right triangle:

  • Slope = Rise / Run
  • Slope(%) = (Rise / Run) × 100
  • Angle = arctan(Rise / Run)
  • Length = √(Rise² + Run²)
  • Ratio 1:N means Slope = 1/N

Use consistent units for rise, run, and length.

How to use this calculator

  1. Select an input method that matches your available measurements.
  2. Choose a unit system, then enter rise and the needed fields.
  3. Optional: set target limits for ratio and percent slope checks.
  4. Press Calculate to view results above the form.
  5. Download CSV or PDF to save and share calculations.

Example data table

Scenario Rise (m) Run (m) Slope (%) Ratio (1:N) Angle (deg) Length (m)
Gentle access0.7598.331:124.769.03
Space limited0.66101:105.716.03
Steeper service0.43.212.51:87.133.22

Example values are illustrative and not project-specific.

Ramp geometry in one triangle

A straight ramp can be treated as a right triangle where rise is vertical change and run is horizontal distance. The calculator converts common units automatically, then reports slope as rise/run, percent grade, angle, and ramp length. Work in mm, cm, m, inches, or feet without manual conversions.

Interpreting slope, percent, and ratio

Slope is unitless, percent grade is slope × 100, and ratio 1:N is the inverse of slope. For example, a 1:12 ramp equals 8.33% and an angle of about 4.76°. These equivalent views help teams communicate intent across drawings and field notes. For ratio inputs, run equals rise multiplied by N.

Working with limited site space

If the available run is short, the rise forces a steeper grade. Use the Run + Angle or Rise + Run methods to test alternatives quickly. Small increases in run can reduce percent noticeably, improving comfort for pedestrians, carts, and wheelchairs. When space is tight, add landings or switchbacks to gain run safely.

Length along the surface

Surface length matters for materials, handrails, and cost. The calculator uses √(rise² + run²) to estimate ramp length for ordering finishes or checking whether a ramp fits between landings without exceeding the available path. Length also supports takeoffs for edge protection, tactile strips, and drainage slopes.

Angle as a measurement check

Field teams often measure angles with digital inclinometers. By entering rise and angle, you can back-calculate run and confirm whether the built slope matches the design. Angles near 0° represent gentle ramps; steep ramps approach 90°.

Target checks and compliance planning

Projects may set a minimum ratio or maximum percent grade based on accessibility goals or internal standards. Enter your targets to get a clear PASS/FAIL message. Use the checks to compare layout options during early planning, then lock the selected geometry for detailing.

Scenario comparison with the example table

The example table shows how a 0.75 m rise needs about 9.00 m run for an 8.33% grade. A 0.40 m rise over 3.20 m run is 12.50%, which may feel steep. Add your own rows to evaluate options like 1:16 (6.25%) or 1:20 (5.00%).

Documenting results for teams

After calculation, export a CSV for spreadsheets or a PDF for site packages. The downloads capture the key numbers and your target checks, supporting reviews, submittals, and coordination meetings. Consistent reporting reduces rework and clarifies decisions.

FAQs

1) What is the difference between run and ramp length?

Run is the horizontal distance on plan. Ramp length is the sloped surface distance. Length is always longer than run and is calculated using the Pythagorean relationship between rise and run.

2) How do I enter a ratio like 1:12?

Choose Rise + Ratio (1:N). Enter the rise and set N to 12. The calculator computes run as rise×12, then reports percent grade, angle, and ramp length.

3) Which unit should I select for my project?

Select the unit that matches your measurements on site or drawings. All length fields use the same unit, and results are displayed in that unit while calculations remain consistent internally.

4) Why does the calculator show PASS or FAIL?

PASS/FAIL compares your ramp against the target minimum ratio and maximum percent grade you entered. It helps you quickly screen options during layout and keep grades within your project limits.

5) Can I use an angle from an inclinometer?

Yes. Select a method that includes Angle, then enter the measured degrees and one length value. The tool will back-calculate the missing side and report the corresponding slope and ratio.

6) What if my ramp requires multiple segments?

Calculate each segment separately using its rise and run. Then document each segment’s slope and provide landings between segments as required by your design and local standards.

7) How do the CSV and PDF downloads help?

CSV supports scenario comparison in spreadsheets, while PDF is useful for sharing in submittals and site packs. Both capture the computed geometry and your target-check outcomes for traceable decisions.

Build safer access routes with accurate ramp slope checks.

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