Driveway slope calculator
Driveway grade is rise ÷ horizontal run × 100. A 3 ft rise over 30 ft is a 10% grade, or 5.7°. How steep is too steep? The answer depends on local limits, traction, drainage, and the transitions your car has to cross.
5.7° incline · 1 ft of rise per 10 ft of horizontal run
This is an average between two points. Check the steeper sections and the street and garage transitions separately.
What is the maximum driveway slope?
There is no single maximum that applies to every residential driveway. Your jurisdiction may regulate the apron, the full driveway, pedestrian crossings, and changes in grade differently. A permitted grade also does not guarantee your particular vehicle will clear it.
For a concrete example, Tennessee's April 2026 state highway access manual recommends 10% and sets a 15% limit for certain residential driveway portions within the right-of-way on roads without curb and gutter. It also places separate limits on grade changes. Those rules are specific to that setting, not a national residential standard. Read TDOT's criteria, page 3-51.
| Grade | Rise over 20 ft | Angle | What the number tells you |
|---|---|---|---|
| 2% | 0.4 ft / 4.8 in | 1.1° | A small fall. Local depressions can still hold water. |
| 5% | 1 ft | 2.9° | Check where runoff goes and how the apron joins the street. |
| 10% | 2 ft | 5.7° | Assess traction and the entry and exit transitions. |
| 15% | 3 ft | 8.5° | A steep layout that warrants a site-specific design review. |
| 20% | 4 ft | 11.3° | Do not assume this is permissible or usable for your vehicle. |
How steep is too steep for your driveway?
Your car scrapes
A short, sharp entry can catch a low front spoiler even on a modest average grade. Check the front lip and overhang with the vehicle clearance calculator. Underbody contact at a crest needs a separate check.
Water runs toward the garage
Measure the final section separately. Ask a contractor where the water will discharge and whether a drain or a revised profile is needed.
Traction is unreliable
Wet leaves, ice, surface finish, and tires matter alongside grade. Explain your winter conditions and vehicle use before choosing a paving specification.
Measure the part that causes the problem
- For an overall grade: measure the elevation difference between two points and their horizontal separation. A level and tape can cover short sections; a survey provides a site profile.
- For a steep patch: repeat over that section. A driveway that rises and then falls can have a zero net grade and still contain steep sections.
- For scraping: measure the grade on each side of the transition. Overall rise and run cannot describe a curb lip or a sharp crest.
The main satellite estimator can help measure area and show a terrain-based grade estimate. Elevation data may miss short transitions and surface details. Use on-site measurements for clearance decisions or a grading plan.
Driveway grade questions
Is a 10% driveway slope the same as 10 degrees?
No. A 10% grade is about 5.7°. A 10° incline is about 17.6%. Convert grade to degrees with arctan(grade ÷ 100); convert degrees to grade with tan(angle) × 100.
Is a 15% driveway too steep?
It is steep enough to check local requirements, vehicle transitions, drainage, and traction before relying on it. Fifteen percent is not a universal approval threshold or a guarantee that a low car can enter.
What is the minimum driveway slope for drainage?
There is no single number that resolves drainage for every surface and site. The finished profile must carry water to an appropriate outlet without trapping it in low spots. An average grade alone does not show cross-slope or depressions.
Does a steeper driveway cost more to pave?
It can if it needs regrading, drainage, retaining work, or difficult equipment access. Start with the asphalt cost calculator, then ask a contractor to price those items separately.
Want local contractors to price the work?
Measure your driveway in the main estimator and get a planning budget first. On the results screen, choose “Email me contractor options” if you want help finding someone. We check availability in your area; sending a request is optional.
Method: rise/run geometry. Content reviewed September 12, 2026. Calculated grades describe your inputs, not a site inspection.