1 in 5. That is 20%, or about 11 degrees, and it is the usual maximum for a residential driveway in Queensland.
You can go to 1 in 4 — 25%, about 14 degrees — but only if the steep section stays short and is eased in at both ends. The conditions are the part people miss.
The numbers, three ways
Builders say ratios. Homeowners and search engines say percentages. Occasionally something says degrees. Same thing.
| Ratio | Percentage | Degrees | Meaning |
|---|---|---|---|
| 1 in 4 | 25% | 14.0° | Steepest allowed, short runs only |
| 1 in 5 | 20% | 11.3° | The standard maximum |
| 1 in 6 | 16.7% | 9.5° | Comfortable |
| 1 in 8 | 12.5% | 7.1° | Transition grade |
| 1 in 20 | 5% | 2.9° | Near flat |
Divide 1 by the second number for the percentage: 1 ÷ 5 = 20%. A bigger second number means a flatter driveway.
When 1 in 4 is allowed
Queensland's rule for driveways sits in NMP 1.1 of the Queensland Development Code. It offers two acceptable solutions: a straightforward 1 in 5 maximum, or 1 in 4 subject to conditions.
Those conditions are where drawings get knocked back:
- The length steeper than 1 in 5 must not exceed 6 metres.
- There must be a transition at each end of the steep section.
- Each transition must be at least 1 metre long and no steeper than 1 in 8.
A 7-metre run at 1 in 4 does not comply however gentle its transitions. An 800 mm transition does not comply however shallow its grade. On a short block those two conditions bind long before the maximum gradient does.
The maximum is rarely the problem
A driveway can sit under every limit and still ground a car. What does the damage is how *abruptly* the slope changes, not how steep it gets.
Leaving a flat street onto a 1 in 4 driveway at a single sharp break drops the front bumper toward the ground while the rear wheels are still level. Spread that same change over a metre or more and the car rides through untouched.
That is what the transition rule exists for, and it is why rate of grade change matters more than the headline number.
Checking your own
- Measure the height difference between the street boundary and the garage floor.
- Divide it by the driveway length. A 1.5 m rise over 8 m is 1 in 5.3.
- Find the steepest section, not the average — that is the number that governs.
- If any part exceeds 1 in 5, measure how long that run is. Over 6 m and it does not meet the concession.
- Check both ends of the steep part for at least 1 m of easing.
For the full picture, including how councils and AS 2890.1 fit in, see driveway gradients in Queensland.
Disclaimer
General information, not advice. This summarises QDC NMP 1.1 as published rather than reproducing it. NMP 1.1 is a non-mandatory part of the code, and local planning schemes, council standard drawings and conditions on individual approvals may require something different. Confirm with your council or a qualified certifier.
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