Braillito Maps · Calculator
ADA ramp calculator
Enter the height the ramp has to rise and pick a standard: the calculator gives the minimum length, the steepest slope allowed, how many runs and landings it needs, the minimum width and whether it needs handrails, with the section each figure comes from. It covers the 2010 ADA Standards, and the codes of Spain, Argentina, Chile and Peru.
This calculator is a guide: it does the arithmetic with the figures of the standard you pick and shows where each one comes from. It does not replace the standard or a design. The code in force where you build and the professional in charge of the work make the call.
Size your ramp
The calculator needs JavaScript. Without it, the tables of each standard are below, under “Every standard in one table”.
ADA ramp length by rise
The minimum length for common rises, landings between runs included. The existing-building column applies only where there is no room for 1:12.
| Rise | New construction (1:12) | Existing building (Table 405.2) |
|---|---|---|
| 3 in | 3 ft (0.92 m) at 1:12 (8.33 %) | 2 ft (0.61 m) at 1:8 (12.5 %) |
| 6 in | 6 ft (1.83 m) at 1:12 (8.33 %) | 5 ft (1.53 m) at 1:10 (10 %) |
| 12 in | 12 ft (3.66 m) at 1:12 (8.33 %) | same as new construction |
| 18 in | 18 ft (5.49 m) at 1:12 (8.33 %) | same as new construction |
| 24 in | 24 ft (7.32 m) at 1:12 (8.33 %) | same as new construction |
| 30 in | 30 ft (9.15 m) at 1:12 (8.33 %) | same as new construction |
| 36 in | 41 ft (12.50 m), 2 runs at 1:12 (8.33 %) | same as new construction |
| 48 in | 53 ft (16.16 m), 2 runs at 1:12 (8.33 %) | same as new construction |
How the calculator works
A ramp’s length is its rise divided by its slope: at 1:12, every inch of rise takes 12 inches of run. What changes from one standard to another is how steep it can be, whether that depends on the rise or on the length, and how often it needs a landing. The calculator measures everything horizontally, splits the rise into equal runs and adds the landings between runs.
- ADA. Every run is 1:12 at most and rises 30 inches (760 mm) at most, with a landing at least 60 inches (1525 mm) long at the top and bottom of each run (2010 ADA Standards, 405.2, 405.6 and 405.7). So a ramp needs 12 inches of run per inch of rise, and one more landing for every 30 inches. In existing buildings without room, Table 405.2 allows steeper ramps for rises up to 6 inches (150 mm). The standard is written in inches, so the calculator works in inches and converts with 1 in = 25.4 mm.
- Spain. The slope depends on the length of each run: 10 % under 3 m, 8 % under 6 m and 6 % otherwise, with runs of 9 m at most (CTE DB SUA, SUA 1, 4.3.1 and 4.3.2); the Ministry’s comments make clear these lengths are per run, in horizontal projection (DB SUA with the Ministry’s comments, SUA 1, 4.3.1). The calculator tries equal splits, with 1.50 m landings between runs (CTE DB SUA, SUA 1, 4.3.3), and keeps the shortest; if one with fewer, gentler runs also complies, it shows that too.
- Argentina. The slope comes from the rise, with one table for indoor ramps and another for outdoor ones, and no run is longer than 6.00 m without a 1.50 m landing (Decreto 914/1997, A.1.4.2.2.1 to A.1.4.2.2.3). The published text lost the sign before each lower bound (“0,075 < 0,200”): the calculator takes each bound as the start of the next range, and uses the percent column, the gentler one where it differs from the ratio (8.33 % against 1:12).
- Chile. The slope is 8 % up to 9 m long and rises to 12 % for 1.5 m, following i % = 12.8 − 0.5333 L (OGUC, article 4.1.7, item 2). The calculator finds the shortest length that meets the formula; past 9 m it uses 8 % and splits the ramp into runs of similar length, as the same item asks.
- Peru. The slope comes from the difference in level: 10 % up to 0.30 m and 8 % from 0.31 m to 0.72 m, on ramps 9.00 m long at most followed by a 1.50 m landing (Norma A.120, article 6). The table stops at 0.72 m; above that, the calculator keeps 8 % and says so in the result.
Lengths are rounded up, to the tenth of an inch and to the centimeter, because they are minimums.
For Mexico, the maximum slope by ramp length is in the Spanish guide to NMX-R-050, with its clause, whether it is mandatory and what we know of its status. In Colombia, the ramp dimensions for buildings open to the public are in the technical standard NTC 4143, which Decreto 1538 de 2005, article 9, paragraph makes mandatory but which is not publicly available; what it is and where it fits is in the Spanish guide to NTC 6047.
Every standard in one table
What each standard says about an accessible ramp, with the section for every figure. The calculator works with these rules.
US: 2010 ADA Standards for Accessible Design
| Requirement | What the standard says |
|---|---|
| Steepest slope | 1:12 at most on every run (2010 ADA Standards, 405.2); cross slope 1:48 at most (2010 ADA Standards, 405.3). In existing buildings without room: up to 1:10 for a rise of 6 inches (150 mm) and up to 1:8 for 3 inches (75 mm); never steeper than 1:8 (2010 ADA Standards, Table 405.2). |
| Runs and landings | Each run rises 30 inches (760 mm) at most, with a landing at the top and bottom of every run, at least 60 inches (1525 mm) long and as wide as the widest run (2010 ADA Standards, 405.6 and 405.7). |
| Bottom and top | A landing 60 inches (1525 mm) long at the bottom and the top; where the ramp changes direction, 60 by 60 inches (1525 × 1525 mm) (2010 ADA Standards, 405.7.3 and 405.7.4). |
| Minimum width | 36 inches (915 mm) of clear width, measured between handrails where there are handrails (2010 ADA Standards, 405.5). |
| Handrails | On runs that rise more than 6 inches (150 mm) (2010 ADA Standards, 405.8), on both sides (2010 ADA Standards, 505.2), with the top of the gripping surface 34 to 38 inches (865–965 mm) high (2010 ADA Standards, 505.4) and extending 12 inches (305 mm) beyond the top and bottom of each run (2010 ADA Standards, 505.10.1). |
Spain: Building Code (CTE DB SUA)
| Requirement | What the standard says |
|---|---|
| Steepest slope | On accessible routes, 10 % when the run is under 3 m long, 8 % when it is under 6 m and 6 % otherwise (CTE DB SUA, SUA 1, 4.3.1); the length is that of each run, in horizontal projection (DB SUA with the Ministry’s comments, SUA 1, 4.3.1). Cross slope 2 % at most (CTE DB SUA, SUA 1, 4.3.1). |
| Runs and landings | Runs are 9 m long at most, and between two runs in the same direction there is a landing at least 1.50 m long and as wide as the ramp (CTE DB SUA, SUA 1, 4.3.2 and 4.3.3). |
| Bottom and top | A level surface at least 1.20 m long at the start and end of every run; no door, and no corridor narrower than 1.20 m, within 1.50 m of the start of a run (CTE DB SUA, SUA 1, 4.3.2 and 4.3.3). |
| Minimum width | 1.20 m at least on an accessible route, and more where the building’s evacuation requires it (CTE DB SUA, SUA 1, 4.3.2). |
| Handrails | On both sides and continuous, landings included, when the slope is 6 % or more and the ramp rises more than 18.5 cm; one at 90–110 cm and another at 65–75 cm, extending 30 cm when the run is longer than 3 m, and a 10 cm kerb on open edges (CTE DB SUA, SUA 1, 4.3.4). |
Argentina: Decreto 914/1997
In Argentina, the slope comes from a table, by rise and by whether the ramp is indoors or outdoors (Decreto 914/1997, A.1.4.2.2.1 and A.1.4.2.2.2):
| Rise | Indoor ramp | Outdoor ramp | Landing, per the table |
|---|---|---|---|
| under 0.075 m | 1:5 (20 %) | 1:8 (12.5 %) | no landing |
| 0.075 m to under 0.200 m | 1:8 (12.5 %) | 1:10 (10 %) | no landing |
| 0.200 m to under 0.300 m | 1:10 (10 %) | 1:12 (8.33 %) | no landing |
| 0.300 m to under 0.500 m | 1:12 (8.33 %) | 1:12.5 (8 %) | no landing |
| 0.500 m to under 0.750 m | 1:12.5 (8 %) | 1:16 (6.25 %) | with landing |
| 0.750 m to under 1.000 m | 1:16 (6.25 %) | 1:16.6 (6 %) | with landing |
| 1.000 m to under 1.400 m | 1:16.6 (6 %) | 1:20 (5 %) | with landing |
| 1.400 m or more | 1:20 (5 %) | 1:25 (4 %) | with landing |
| Requirement | What the standard says |
|---|---|
| Runs and landings | No sloped run longer than 6.00 m in horizontal projection without a level landing at least 1.50 m long and as wide as the ramp (Decreto 914/1997, A.1.4.2.2.3). |
| Bottom and top | At the start and end, room for a 1.50 m circle, clear of obstacles and door swings; and where each run starts and ends, a strip of different texture and colour 0.60 m long (Decreto 914/1997, A.1.4.2.2.3). |
| Minimum width | Between 1.10 m and 1.30 m clear, measured between kerbs; wider, with middle handrails where people pass both ways (Decreto 914/1997, A.1.4.2.2.3). |
| Handrails | On both sides, double and continuous: the upper one at 0.90 m and the lower one at 0.75 m, 0.15 m apart, extending 0.30 m at the start and end (Decreto 914/1997, A.1.4.2.2.4); 0.10 m kerbs on both sides (Decreto 914/1997, A.1.4.2.2.3). |
Chile: General Ordinance of Urban Planning and Construction (OGUC)
| Requirement | What the standard says |
|---|---|
| Steepest slope | 8 % up to 9 m long; for a length of 1.5 m it can rise to 12 % at most, following i % = 12.8 − 0.5333 L, where L is the length of the ramp. Slopes under 5 % count as inclined planes (OGUC, article 4.1.7, item 2). |
| Runs and landings | Longer than 9 m, the ramp is split into runs of similar length, with landings at least 1.5 m long and as wide as the ramp; where it turns, the landing fits a 1.50 m circle (OGUC, article 4.1.7, item 2). |
| Bottom and top | It starts and ends on a level surface as wide as the ramp and at least 1.50 m long, outside the door swing, with no change in level where it meets the floor (OGUC, article 4.1.7, item 2). |
| Minimum width | That of the escape route it faces or belongs to; 0.90 m at least where it is not part of one (OGUC, article 4.1.7, item 2). |
| Handrails | On both sides when the ramp is longer than 1.50 m: continuous, at 0.95 m and 0.70 m, extending 0.20 m at the entry and exit; up to 1.50 m, an edge kerb of at least 0.10 m or a railing at least 0.95 m high (OGUC, article 4.1.7, item 2). |
Peru: Technical Standard A.120
| Requirement | What the standard says |
|---|---|
| Steepest slope | 10 % for a difference in level of up to 0.30 m; 8 % from 0.31 m to 0.72 m; cross slope under 2 % (Norma A.120, article 6). |
| Runs and landings | A ramp is 9.00 m long at most, followed by a 1.50 m landing (Norma A.120, article 6). |
| Bottom and top | Start and end are flat and level; landings leave a 1.50 × 1.50 m turning space when the building holds more than 500 people, or a 1.20 m circle otherwise; and tactile warning paving marks the start and end (Norma A.120, article 6). |
| Minimum width | 1.00 m at least, handrails and railings included (Norma A.120, article 6). |
| Handrails | Double handrails, one at 0.85–0.90 m and the other 0.25 m lower, continuous and extending 0.20 m at the start and end (Norma A.120, article 7); on ramps longer than 3.00 m, parapets or railings on open sides (Norma A.120, article 6). |
Frequently asked questions
How do I use the ramp calculator?
Type the rise, the height from the lower floor to the upper one; choose inches or centimeters and a standard, and press Calculate. The answer gives the minimum length, the steepest slope, how many runs and landings, the minimum width and whether handrails are required, each with the section it comes from. What each ADA rule means is explained in the ADA ramp slope guide.
How long does a ramp need to be for a 24-inch rise?
At least 24 ft (7.32 m) of run, in a single run, since 24 inches is under the 30-inch limit per run. It needs handrails, because the run rises more than 6 inches, and a 60-inch landing at the top and bottom (2010 ADA Standards, 405.2, 405.6, 405.7 and 405.8).
How long is an ADA ramp for a 36-inch rise?
At least 41 ft (12.50 m): two runs of 18 inches of rise and 18 feet each, plus a 60-inch (1525 mm) landing between them, because no run may rise more than 30 inches (2010 ADA Standards, 405.2, 405.6 and 405.7). That is why the result is longer than 36 × 12 inches: it counts the landings between runs, but not the ones at the bottom and top.
What ramp length do I need for a 60 cm rise?
Switch the unit to centimeters and type 60. Under the ADA, at least 7.20 m (23 ft 7.5 in) in a single run at 1:12, because 60 cm is about 23.6 inches, under the 30-inch limit per run (2010 ADA Standards, 405.2 and 405.6). Under Spain’s code the same rise takes 9.00 m (29 ft 6.4 in), in 2 runs at 8 % with a landing between them (CTE DB SUA, SUA 1, 4.3.1 to 4.3.3).
What if the ramp does not fit?
In an existing building without room for 1:12, choose “US, existing building (ADA)”: a rise of up to 6 inches (150 mm) may be as steep as 1:10, and up to 3 inches (75 mm) as steep as 1:8 (2010 ADA Standards, Table 405.2), so a 4-inch rise takes 3 ft 4 in (1.02 m) instead of 4 ft (1.22 m). A longer ramp can double back: the length is the same but takes less depth, with a landing at least 60 by 60 inches (1525 × 1525 mm) where it turns (2010 ADA Standards, 405.7.4). An accessible route can also use an elevator or a platform lift instead of a ramp (2010 ADA Standards, 402.2).
Can I enter the rise in centimeters?
Yes: change the unit. The ADA is written in inches, so the calculator works in inches and converts at 1 in = 25.4 mm; the codes of Spain, Argentina, Chile and Peru are in meters. Every length comes in both systems, rounded up to the tenth of an inch and to the centimeter, because they are minimums.
Can I compare the ADA with other countries’ codes?
Yes: keep the rise and change the standard. The menu has the ADA for new construction and for existing buildings, Spain’s Building Code (CTE), Argentina’s Decreto 914/1997 for indoor and outdoor ramps, Chile’s OGUC and Peru’s Norma A.120. For a 36-inch rise, the ADA asks for 41 ft (12.50 m) and Spain’s code 42 ft 5.1 in (12.93 m); the tables further down this page set the rules side by side.
More accessibility guides
- ADA ramp slope: the 1:12 rule, width, landings, handrails and edge protection.
- ADA compliance: a checklist for small businesses, with the 2010 Standards section behind each item.
- ADA door width: 32 inches of clear width, maneuvering space, thresholds, hardware and opening force.
- Accessible parking: ADA parking requirements: how many spaces, how wide, the access aisle and the sign.
- All accessibility guides
Sources
Every figure in this guide comes from one of these official texts, which we read in October 2026.
- 2010 ADA Standards for Accessible Design. U.S. Department of Justice, published September 15, 2010; required for new work since March 15, 2012.
- Código Técnico de la Edificación, Documento Básico SUA (Seguridad de utilización y accesibilidad). Ministerio de Transportes, Movilidad y Agenda Urbana (España), version with the amendments of Real Decreto 450/2022.
- Documento Básico SUA con comentarios del Ministerio. Ministerio de Vivienda y Agenda Urbana (España), articles of June 14, 2022, comments of July 15, 2024.
- Decreto 914/1997, reglamentación de los artículos 20, 21 y 22 de la Ley 22.431 (modificados por la Ley 24.314). Presidencia de la Nación (Argentina), original text of 1997.
- Ordenanza General de Urbanismo y Construcciones (OGUC), Decreto 47 de 1992 del Ministerio de Vivienda y Urbanismo. Biblioteca del Congreso Nacional de Chile, latest version, in force since October 2, 2026.
- Norma Técnica A.120 «Accesibilidad universal en edificaciones» del Reglamento Nacional de Edificaciones. Ministerio de Vivienda, Construcción y Saneamiento (Perú), Resolución Ministerial 075-2023-VIVIENDA, El Peruano, February 17, 2023.
- Decreto 1538 de 2005, accesibilidad al medio físico (compilado en el Decreto 1077 de 2015). Diario Oficial 45.913 (Colombia), en el normograma del Ministerio TIC, 17 de mayo de 2005.
Braillito Maps
Find places with ramps, accessible toilets or tactile paving near you in Braillito Maps
In Braillito Maps, every place answers ten questions. One is the ramp: whether you can get in without steps, by ramp or at street level. It is built by the people who need it, and every place gets a score out of ten.
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