How long does a 1 in 14 ramp need to be?
Published · Updated · By Sai Nath
A 1 in 14 ramp is 14 mm long for every 1 mm of rise, so the horizontal run is the rise × 14: 150 mm of rise needs 2.1 m. The sloped surface is about 0.25% longer. A 1 in 14 gradient is 7.14% or 4.09 degrees. The gradient allowed depends on the country and the building.
How do you work out ramp length from the height?
Multiply the rise by 14. Rise and run must be in the same unit.
- Measure the rise: the vertical height from the bottom surface to the top surface, in millimetres.
- Run = rise × 14. This is the horizontal distance the ramp covers.
- Surface length = rise × 14.036. This is what a tape reads along the ramp, and what you buy timber, decking or formwork for.
Worked example: a deck 450 mm high. Run = 450 × 14 = 6300 mm (6.3 m). Surface = 450 × 14.036 = 6316 mm. The 14.036 is √(14² + 1²) = √197, from Pythagoras. The surface is only 16 mm longer than the run, so for a rough order the run will do.
The usual mistake is dividing when you should multiply. A 450 mm rise at 1 in 14 is 6300 mm of run, not 32 mm. Check it the other way: 450 ÷ 6300 = 0.0714, which is 7.14%.
How long is a 1 in 14 ramp for common heights?
The table gives the run and the sloped surface for rises from 100 mm to 1200 mm. Run = rise × 14; surface = rise × 14.036, rounded to 1 mm.
| Rise (mm) | Horizontal run (mm) | Sloped surface (mm) |
|---|---|---|
| 100 | 1400 | 1404 |
| 150 | 2100 | 2105 |
| 190 | 2660 | 2667 |
| 200 | 2800 | 2807 |
| 250 | 3500 | 3509 |
| 300 | 4200 | 4211 |
| 450 | 6300 | 6316 |
| 500 | 7000 | 7018 |
| 600 | 8400 | 8421 |
| 750 | 10500 | 10527 |
| 900 | 12600 | 12632 |
| 1000 | 14000 | 14036 |
| 1200 | 16800 | 16843 |
190 mm is a typical riser height, so a single step needs 2660 mm of run. For a rise not in the table, multiply by 14. Imperial: 6 in of rise needs 84 in (7 ft) of run, because the ratio does not depend on the unit.
How much rise can a 1 in 14 ramp cover in a given length?
Divide the run by 14. Over 4 m the ramp can rise 4000 ÷ 14 = 286 mm; over 5 m, 5000 ÷ 14 = 357 mm; over 9 m, 9000 ÷ 14 = 643 mm.
| Run available | Rise covered at 1 in 14 (mm) |
|---|---|
| 2 m | 143 |
| 4 m | 286 |
| 5 m | 357 |
| 9 m | 643 |
| 10 m | 714 |
If your run is short, a steeper ramp is not the only answer. The 450 mm deck above over 5 m of run would be 450 ÷ 5000 = 9%, or 1 in 11.1, which is steeper than 1 in 14. Options are a longer route, a turn with a landing, or a lower rise. Don’t round a 1 in 11 up to “about 1 in 14”.
What is a 1 in 14 ramp in degrees and percent?
1 in 14 is 7.14% and 4.09 degrees, or 71.4 mm of rise per metre of run (1000 ÷ 14). For a ratio 1 in N:
- Percentage = 100 ÷ N. 100 ÷ 14 = 7.14%.
- Angle = arctan(1 ÷ N). arctan(1 ÷ 14) = 4.09 degrees.
- Millimetres of rise per metre = 1000 ÷ N. 1000 ÷ 14 = 71.4 mm.
| Ratio | Slope (%) | Angle (°) | Rise per metre (mm) |
|---|---|---|---|
| 1 in 8 | 12.50 | 7.13 | 125.0 |
| 1 in 10 | 10.00 | 5.71 | 100.0 |
| 1 in 12 | 8.33 | 4.76 | 83.3 |
| 1 in 14 | 7.14 | 4.09 | 71.4 |
| 1 in 15 | 6.67 | 3.81 | 66.7 |
| 1 in 20 | 5.00 | 2.86 | 50.0 |
More conversions are in slope percentage to degrees. The same sum for drainage falls, where the ratios are much flatter, is in how to calculate fall.
Is a 1 in 14 ramp allowed?
1 in 14 is a ratio, and only sometimes a rule. In Australia it is the steepest gradient allowed on the step-free access path to a house built to the ABCB Standard for Livable Housing Design, and in England, for buildings other than dwellings, Approved Document M gives it by interpolation for a 4 m going. Otherwise the limit depends on the country, the type of building and how long the ramp is. Ask your certifier or council before you build. The figures below are from official documents.
Checked on 28 October 2026.
England
Approved Document M sets gradient limits by the length of the flight, and says gradients should be as shallow as practicable. 1 in 14 appears only by interpolation.
| Building | Rule | Source |
|---|---|---|
| Buildings other than dwellings | Going of 10 m: maximum 1:20, rise 500 mm. Going of 5 m: 1:15, rise 333 mm. Going of 2 m: 1:12, rise 166 mm. No flight over 10 m or 500 mm of rise. Between 2 m and 10 m it is acceptable to interpolate, “1:14 for a 4m going or 1:19 for a 9m going”. | Approved Document M Volume 2 (2024 amendments), paragraph 1.26 and Table 1 |
| Dwellings, external ramp (M4(1)) | Flights up to 1:15 not more than 10 m long; up to 1:12 not more than 5 m long. Clear width 900 mm, with top and bottom landings. | Approved Document M Volume 1 (2015 edition, 2016 amendments), paragraph 1.7 |
| Dwellings, M4(2) | Gradient between 1:20 and 1:12. Flight length from Diagram 2.1: at 1:14 a flight may rise 286 mm, about 4 m long. Clear width 900 mm (private) or 1200 mm (communal). | Same Volume 1, paragraph 2.10 and Diagram 2.1 |
| Dwellings, M4(3) | Gradient between 1:20 and 1:15. Clear width 1200 mm, landings at top and bottom and between flights. | Same Volume 1, paragraph 3.10 |
The 286 mm in the M4(2) diagram matches the table above: 4000 ÷ 14 = 286. Government page for the document: Approved Document M on GOV.UK.
Australia
For a house, the NCC 2022 Housing Provisions give a general ramp rule, and it is not an accessible-ramp rule.
- Housing, general: an external ramp to a doorway, or a ramp within a building, must have a gradient not steeper than 1:8, with landings at the top and bottom and at intervals not greater than 15 m (clause 11.2.3). A landing must be at least 750 mm long and not steeper than 1:50 (clause 11.2.5). Source: NCC 2022 Housing Provisions, Part 11.2. The same page notes that where a ramp is provided to meet the ABCB Standard for Livable Housing Design, that standard applies.
- Livable housing: for a house (Class 1a) built to the ABCB Standard for Livable Housing Design, the step-free access path to an entrance door must be no steeper than 1:14 (clause 1.1(2)(a)(ii)). Ramping on that path may total no more than 9 m at 1:14 or 15 m at 1:20, and each end of a ramp needs a landing at least 1200 mm long (clause 1.1(4)). State variations apply, so check whether your state applies the Standard. Source: NCC 2025 Livable Housing Design, Part 1.
- Accessible ramps in buildings: in a building required to be accessible, a ramp (other than a fire-isolated ramp) must comply with clause 10 of AS 1428.1, and a series of connected ramps must not rise more than 3.6 m in total (clauses D4D4 and D4D12). Source: NCC 2022 Volume One, Part D4.
The NCC pages above do not give the accessible gradient itself. That is in AS 1428.1, which is sold by Standards Australia, and this page does not quote its gradient, flight length or landing sizes. You will often see “1 in 14” quoted for accessible ramps in other buildings too; for those, check it against AS 1428.1 or ask your certifier. Don’t take 1:8 from the housing rule as a ramp for wheelchairs.
New Zealand and elsewhere
Acceptable Solution D1/AS1, Table 3, gives these maximum slopes: 1:12 for an accessible ramp, 1:10 for a common ramp subject to wetting, 1:8 for a common ramp normally dry, and 1:3 for a service ramp. D1/AS1 is one way to meet Building Code clause D1, and your council decides what it accepts. Source: D1/AS1 Access Routes, Amendment 6 (PDF). Figures for anywhere else are not covered here.
What gradient should a wheelchair ramp be?
As shallow as the site allows. Approved Document M says gradients should be as shallow as practicable, because steep ones are hard for people who lack the strength to propel themselves up or to slow down when going down. England’s tables run from 1:20 for long flights to 1:12 for short ones, as above, and New Zealand’s D1/AS1 gives 1:12 for an accessible ramp. For an Australian house built to the Livable Housing Design Standard the access path is 1:14 at most; for accessible ramps in other buildings, the number is in AS 1428.1. Either way, the official limit is a maximum, not a target.
What about landings, width and handrails?
The ramp’s length is only part of it. In England, for buildings other than dwellings, Approved Document M Volume 2 paragraph 1.26 also asks for a surface width of at least 1.5 m between walls, upstands or kerbs, a landing of at least 1.2 m long at the foot and head clear of door swings, and intermediate landings at least 1.5 m long. It also asks for an alternative means of access, such as a lift, where the total rise is over 2 m. Australian housing landings are in the NCC clause quoted above. MeisterCalc does not plan landings, width, handrails or edge protection, so add each landing’s length to the run separately. For the 450 mm deck with a 1200 mm landing at each end, that is 6300 + 1200 + 1200 = 8700 mm of overall length along the route.
If the ramp meets a stair at the top or bottom, the going and rise rules are different: see stair rules in Australia.
How do you set out a ramp on site?
- Measure the rise from the lower finished surface to the top finished surface. Use a level and a straight edge, or a dumpy level if the ground is uneven; the sums are in how to use a dumpy level.
- Run = rise × 14. Mark that distance out from the top edge, along the line the ramp will take.
- Pull a string line from the top edge to the mark and make it level at the top.
- Check the drop at the bottom mark against the rise. It should equal the rise you measured. Check halfway: it should be half the rise below the top.
- Cut timber or decking to the sloped surface length (rise × 14.036), not the run. Add the length of any landing separately.
How do you do it in MeisterCalc?
The app has no “1 in N” field. Use the Pitch calculator, which solves rise, run, angle, % grade and hypotenuse from any two inputs. The hypotenuse is the true sloped length: what a tape reads along the surface.
- Open MeisterCalc and tap Pitch on the home screen, then choose the Rise + Run mode.
- Enter the Rise: 450 mm. Enter the Run: 6300 mm.
- The Angle shows 4.09°, the % Grade 7.14%, the Slope Ratio 0.0714 and the Hypotenuse 6316.1 mm. That confirms the ratio is 1 in 14.
To start from the gradient instead, choose Rise + Grade, enter the rise and a grade of 7.1429. The Run comes out at about 6300 mm; it is not exactly 6300 because 7.1429 is rounded. A grade of 7.1 gives about 1 in 14.08, so use the extra decimals.
What the app doesn’t do
- No “1 in N” input and no ramp calculator: Pitch gives rise, run, angle, % grade and sloped length.
- No landings, handrails, ramp width, edge protection or multi-flight planning.
- No gradient limits for any country, and no check against the NCC, AS 1428.1 or Approved Document M. Building rules are set by those documents, the NZ Building Code and your local council, not by the app.
Quick answers
What is a 1 in 14 gradient?
A rise of 1 unit for every 14 units of horizontal run: 7.14%, or 4.09 degrees.
How long is a 1 in 14 ramp in mm?
Rise × 14. A 150 mm rise is 2100 mm; a 300 mm rise is 4200 mm; a 600 mm rise is 8400 mm.
What is 1 in 14 in degrees?
4.09 degrees, from arctan(1 ÷ 14).
Is 1 in 12 steeper than 1 in 14?
Yes. 1 in 12 is 8.33% or 4.76 degrees; 1 in 14 is 7.14%. The smaller the second number, the steeper the ramp.
Try it
Pitch is among the MeisterCalc calculators that unlock with a weekly subscription that starts with a 3-day free trial, or with a one-time lifetime unlock; Google Play shows the prices in your currency. Concrete, Stairs and Check Square are free. It works offline, on Android 7.0 or later. There’s no iPhone version yet; you can join the iOS waitlist.