Retaining Wall Pressure Calculator
Calculate lateral earth pressure on a retaining wall using Rankine theory. Get the active, at-rest or passive coefficient, the pressure at the base, the total thrust per unit length, where it acts and the overturning moment — with optional backfill slope and surcharge, in metric or imperial units.
Input
Height of retained soil, measured from the base of the wall.
kN/m³ in metric, pcf in imperial. Typical granular fill: 17–20 kN/m³ (110–125 pcf).
Slope of the ground behind the wall. Ignored for at-rest pressure.
Load on the ground surface behind the wall: kPa in metric, psf in imperial.
Output
| Property | Value |
|---|---|
| No data yet | |
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/retaining-wall-pressure-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"units": "metric",
"state": "active",
"height": "4",
"unitWeight": "18",
"frictionAngle": "30",
"backfillSlope": "0",
"surcharge": "10"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `retaining-wall-pressure-calculator` tool (Retaining Wall Pressure Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
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<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
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Guides
A retaining wall holds back soil, and that soil pushes sideways. How hard depends on the soil's weight and friction angle, the wall's height, and whether the wall is free to move. This calculator uses Rankine earth-pressure theory to give you the pressure coefficient, the pressure at the base, the total thrust per metre (or foot) of wall, the height at which it acts, and the overturning moment about the base.
How to use it
- Pick a unit system — metric (m, kN/m³, kPa) or imperial (ft, pcf, psf).
- Choose the earth pressure state: active if the wall can tilt or slide slightly away from the soil (the usual design case for gravity and cantilever walls), at-rest for rigid walls that cannot move such as basement walls, or passive for soil in front of a wall resisting movement.
- Enter the wall height, the soil unit weight and the friction angle φ.
- Optionally add a backfill slope and a uniform surcharge (traffic, stored material, a building nearby).
The formulas
- Active: Ka = tan²(45° − φ/2) for level ground. Passive: Kp = tan²(45° + φ/2).
- At-rest: K₀ = 1 − sin φ (Jaky).
- Sloping backfill uses the Rankine expressions with cos β; the slope cannot exceed φ.
- Soil thrust P = ½ K γ H², acting at H/3 above the base. Surcharge thrust = K q H, acting at H/2. The tool combines both into one resultant and moment.
Limits worth knowing
This is a cohesionless, dry-soil model. It ignores cohesion, groundwater and wall friction. A water table behind the wall adds hydrostatic pressure and can double the load, so treat the result as a first estimate, not a stamped design. For sloped backfill, the thrust acts parallel to the slope; horizontal and vertical components are listed.
Privacy
All calculations run in your browser. Nothing is sent anywhere.
Related tools
Working with soil or foundation quantities? Convert kN, kPa and psf with the Pressure Converter or the Unit Converter.