Concrete Ramp Calculator
Estimate concrete volume, ramp slope, surface length, wastage and indicative material cost for a concrete ramp.
- Rise is taken from the vertical height entered.
- Width is taken from the clear ramp width entered.
- Run is taken from the horizontal ramp length entered or calculated from the target slope.
- Ramp volume includes any thin-end thickness entered.
- Wastage allowance: 10%
- Slope check compares the calculated slope against the maximum desired slope.
- Landings use the recommended concrete thickness.
- Ramp purpose is used to recommend concrete thickness, sub-base and reinforcement.
- Sub-base depth defaults to the recommended depth unless changed in Advanced.
- Results are for planning and material estimation only.
Use this Concrete Ramp Calculator to estimate the amount of concrete required for a ramp, calculate slope ratios, check accessibility gradients, estimate material costs and determine sub-base requirements.
Whether you’re building a wheelchair access ramp, garage ramp, garden ramp or commercial concrete access route, this calculator helps estimate concrete volumes, wastage allowances and ordering quantities before construction begins.
The calculator supports both metric and imperial measurements and includes advanced recommendations for concrete thickness, MOT Type 1 sub-base depth, reinforcement mesh requirements, excavation depth, landings and slope compliance checks.
PRO TIP: For wheelchair ramps and accessibility projects, check current UK Building Regulations and accessibility guidance before construction. A ramp that meets volume requirements may still be too steep for safe use.
How to Use this Concrete Ramp Calculator
Step 1: Enter Ramp Dimensions
Input:
- Ramp rise (vertical height)
- Ramp width
- Ramp run
Alternatively, select Target Slope Ratio and choose:
- 1:12 Accessibility Ramp
- 1:15 Gentler Ramp
- 1:20 Very Gentle Ramp
- Custom Ratio
The calculator will determine the required horizontal run automatically.
Step 2: Define Concrete Profile
Enter the thin-end thickness if the ramp starts on an existing slab or base.
For a standard wedge-shaped ramp, leave this value at zero.
Step 3: Add Wastage
Enter a wastage percentage to allow for:
- Spillage
- Over-ordering
- Uneven ground
- Site adjustments
A 10% allowance is commonly used for concrete projects.
Step 4: Add Material Costs
Optional cost inputs include:
- Concrete cost per m³
- Sub-base cost
- Reinforcement or mesh cost
This provides a project material estimate.
Step 5: Use Advanced Options
Advanced mode includes:
- Top landing length
- Bottom landing length
- Custom sub-base depth
- Reinforcement area calculations
- Excavation calculations
- Order quantity rounding
- Maximum slope compliance checks
Step 6: Review Results
The calculator displays:
- Ramp run
- Surface length
- Slope ratio
- Grade percentage
- Ramp angle
- Concrete volume
- Wastage volume
- Total concrete required
- Sub-base quantities
- Reinforcement area
- Estimated material costs
Results Explanation
Ramp Run
The horizontal distance covered by the ramp from start to finish.
Surface Length
The actual distance travelled along the ramp surface. This is always slightly longer than the horizontal run because it follows the slope.
Slope Ratio
The ramp gradient is expressed as:
1:X
For example:
1:12 means the ramp rises 1 metre vertically for every 12 metres of horizontal run.
Grade Percentage
The ramp slope is expressed as a percentage.
This is calculated by dividing the rise by the run and multiplying by 100.
Ramp Angle
The angle of incline is measured in degrees.
Steeper ramps produce larger angles.
Ramp Volume Before Wastage
The calculated concrete volume required for the ramp section only, excluding any landings and wastage allowance.
Landing Volume
Additional concrete volume required for any top or bottom landings entered in Advanced Mode.
Concrete Before Wastage
The combined concrete volume for the ramp and any landings before wastage is added.
Concrete With Wastage
The final concrete quantity after applying the selected wastage allowance.
This is typically the volume used when ordering ready-mix concrete.
Wastage Added
The additional concrete volume included to account for spillage, uneven ground, over-excavation and site adjustments.
Recommended MOT Type 1
The estimated quantity of MOT Type 1 aggregate required beneath the ramp is based on the ramp footprint and sub-base depth used in the calculation.
Mesh Required
The approximate reinforcement mesh coverage area required for the ramp and any landings.
This figure represents the coverage area rather than the number of mesh sheets required.
Recommended Concrete Thickness
The suggested concrete thickness is based on the selected ramp purpose.
Vehicle and commercial ramps generally require thicker concrete than pedestrian and wheelchair ramps.
Recommended Sub-base Depth
The suggested compacted MOT Type 1 depth for the selected ramp purpose.
Different ramp types require different levels of support depending on expected loading.
Sub-base Depth Used
The actual sub-base depth used in the calculations.
If a custom depth is entered in Advanced Mode, this may differ from the recommended depth.
Reinforcement Recommendation
A guidance recommendation based on the selected ramp purpose.
Some ramps may not require reinforcement, while vehicle and commercial ramps typically benefit from reinforcement mesh.
Excavation Depth
The total construction depth is calculated from the concrete thickness and sub-base depth.
This helps estimate how deep the ground may need to be excavated before construction.
Excavation Volume
The estimated volume of material that may need to be excavated to install the ramp and supporting layers.
This can be useful when estimating spoil removal and groundworks.
Material Cost
The estimated total material cost is based on any concrete, sub-base and reinforcement prices entered into the calculator.
Estimated Bags
The approximate number of 25kg concrete bags required when using bagged concrete instead of ready-mix.
Bag estimates are rounded up to ensure sufficient material is available on site.
UK Wheelchair Ramp Gradient Guidance
For wheelchair access ramps, the concrete volume is only part of the design. The ramp also needs to be shallow enough to use safely, with suitable landings, surface finish and construction depth.
In England, Approved Document M gives guidance on access to and use of buildings. For ramped access, the maximum gradient depends on the horizontal slope of each ramp flight. A shorter ramp may be steeper, but longer ramps should be gentler. Approved Document M lists the following limits:
| Ramp Going | Maximum Gradient | Maximum Rise |
|---|---|---|
| 10m | 1:20 | 500mm |
| 5m | 1:15 | 333mm |
| 2m | 1:12 | 166mm |
For ramp lengths between these values, the guidance allows interpolation. For example, a ramp with a 4m going may use a gradient around 1:14, while a 9m going may use a gradient around 1:19. Steeper gradients can make wheelchair access more difficult and may not meet accessibility requirements.
What do 1:12, 1:15 and 1:20 mean?
A ramp gradient of 1:12 means the ramp rises 1 unit vertically for every 12 units of horizontal run. For example, a 300mm rise would need a 3.6m run at 1:12.
- 1:12 – Steepest commonly referenced wheelchair ramp gradient, usually only suitable for short rises.
- 1:15 – Gentler and often more practical where space allows.
- 1:20 – Very gentle; generally easier to use and often treated more like a sloped approach than a steep ramp.
When are landings needed?
Level landings should normally be provided at the top and bottom of a ramp, and between ramp flights where the total rise or ramp length requires a break. Landings give wheelchair users, mobility scooter users and pedestrians a safe resting and turning area.
As a practical rule, avoid designing one long continuous ramp without rest points. If the ramp has a high total rise, multiple flights with intermediate landings may be needed. For public, commercial or regulated access routes, confirm the required landing sizes, handrails, edge protection and surface finish against the current Building Regulations and project-specific access requirements.
Building Regulations and accessibility checks
This calculator can estimate ramp run, slope ratio, gradient percentage, ramp angle, concrete volume and material quantities, but it does not replace a compliant access design. For wheelchair access, check the latest Approved Document M guidance, any relevant local Building Control requirements and the specific needs of the building users before construction.
Concrete ramps should also be designed with suitable sub-base support, reinforcement where required, drainage, slip-resistant surface finish and edge protection. A brushed concrete finish is commonly used to improve grip, especially outdoors.
Important: If the ramp is for a public building, commercial premises, rented property, workplace or formal disabled access route, get the design checked by a competent professional or Building Control before pouring concrete.
How the Maths Works
1. Calculate Ramp Run
When using a target slope ratio:
Run = Rise × Slope Ratio
Example:
0.5m rise with a 1:12 slope:
0.5 × 12 = 6m run
2. Calculate Surface Length
Using Pythagoras:
Surface Length = √(Run² + Rise²)
3. Calculate Average Concrete Depth
Average Depth = Thin End Thickness + (Rise ÷ 2)
4. Calculate Ramp Volume
Ramp Volume = Run × Width × Average Depth
This treats the ramp as a wedge-shaped prism.
5. Calculate Landing Volume
Landing Volume = Landing Area × Recommended Concrete Thickness
6. Apply Wastage
Total Concrete = Concrete Volume × (1 + Wastage %)
7. Calculate Grade
Grade (%) = (Rise ÷ Run) × 100
8. Calculate Angle
Angle = arctangent(Rise ÷ Run)
9. Calculate Sub-base Quantity
Sub-base Volume = Area × Depth
The calculator assumes a sub-base density of approximately:
1.7 tonnes per m³
10. Estimate Concrete Bags
The calculator assumes a 25kg bag yields approximately:
0.0125m³ of concrete
Required bags:
Total Volume ÷ Bag Yield
Rounded up to the next whole bag.
Common Mistakes to Avoid
- Confusing rise with surface length
- Measuring the slope instead of the horizontal run
- Forgetting to include landings
- Using no wastage allowance
- Ignoring sub-base requirements
- Ordering exact quantities with no contingency
- Failing accessibility slope requirements
- Omitting reinforcement where ground conditions require it
FAQs
How much concrete do I need for a ramp?
The required volume depends on the ramp rise, width, run length and any landings. This calculator estimates the total concrete volume automatically.
What is the recommended slope for a wheelchair ramp?
A 1:12 slope is commonly used for accessibility ramps, although project-specific requirements may vary.
How thick should a concrete ramp be?
Domestic pedestrian and wheelchair ramps commonly use around 100mm of concrete. Mobility scooter ramps often use around 125mm, while vehicle and commercial ramps typically use around 150mm or more. Actual requirements depend on loading, ground conditions and local regulations.
Do I need reinforcement mesh?
Many ramps benefit from reinforcement to help reduce cracking and improve durability.
What sub-base depth should I use?
A typical sub-base depth is around 100mm, although heavier loads may require deeper construction.
What happens if my ramp is too steep?
The advanced slope check highlights whether the calculated ramp exceeds your selected maximum slope ratio.
How much MOT Type 1 do I need under a concrete ramp?
Most residential concrete ramps require a compacted MOT Type 1 sub-base beneath the concrete. The calculator estimates the quantity required based on the ramp footprint and selected construction depth.
What concrete thickness should I use for a ramp?
Typical residential pedestrian and wheelchair ramps often use around 100mm of concrete, while vehicle ramps commonly require around 150mm. Actual requirements depend on loading, ground conditions and local regulations.
Why does the calculator show excavation depth?
Excavation depth helps estimate how much ground must be removed before installing the sub-base and concrete layers. This is useful when planning labour, spoil removal and overall project costs.
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Disclaimer
- Results are intended for planning and estimating purposes only.
- Site conditions may affect actual material requirements.
- Concrete yields vary by mix design and supplier.
- Accessibility requirements should be verified against current regulations.
- Structural projects may require professional design and approval.
- Always confirm quantities with suppliers before ordering.