Soil Erosion Rate Calculator

Reviewed by the CalculatorHub team, edited by James Graham. Uses the USDA Universal Soil Loss Equation (USLE/RUSLE). Last verified 14 June 2026.

This calculator uses the Universal Soil Loss Equation (USLE), A = R x K x LS x C x P, developed by the USDA Agricultural Research Service (Wischmeier and Smith, 1978). It estimates average annual sheet and rill erosion in tons per acre per year. The equation is the basis of the Revised USLE (RUSLE, USDA Agricultural Handbook 703, 1997) used in conservation planning across the United States and internationally.

R Factor (Rainfall Erosivity) Annual rainfall erosivity index (typical US range: 20-600). See USDA NRCS R factor maps.

K Factor (Soil Erodibility) Soil erodibility factor (typical range: 0.02-0.69). Found in soil survey data.

LS Factor (Slope Length-Gradient) Combined slope length and steepness factor (1.0 = standard 9% slope, 72.6 ft). Computed from topography.

C Factor (Cover Management) Cover factor: 1.0 = bare tilled soil; 0.001 = mature undisturbed forest; cropland typically 0.1-0.5.

P Factor (Support Practice) Conservation practice factor: 1.0 = no practice; contouring/terracing reduces this to 0.1-0.6.

Annual Soil Loss (tons/acre/yr)

Annual Soil Loss (t/ha/yr)

Erosion Severity Class

USLE formula

A = R x K x LS x C x P

Where A = average annual soil loss (tons/acre/year), R = rainfall erosivity factor, K = soil erodibility factor, LS = slope length-gradient factor, C = cover-management factor, P = support practice factor. Source: Wischmeier, W.H. and Smith, D.D. (1978), USDA Agricultural Handbook No. 537.

Erosion severity classes (USDA)

Soil Loss (t/ha/yr)	Class	Description
0-5	None to slight	Tolerable rate
5-11	Moderate	Some management needed
11-22	High	Significant productivity impact
22-33	Very high	Severe management required
33+	Extremely high	Emergency conservation measures

Soil erosion rate calculator: frequently asked questions

What is the Universal Soil Loss Equation (USLE)?

The USLE is an empirical erosion model developed by the USDA Agricultural Research Service. The equation is A = R x K x LS x C x P, where A is average annual soil loss in tons per acre per year. It was developed by Wischmeier and Smith (1978) and is the standard method for predicting sheet and rill erosion.

What is the R factor (rainfall erosivity)?

The R factor is the rainfall and runoff erosivity index. It reflects the erosive energy of rainfall at a location. R values for the continental US range from about 20 in dry western states to over 600 in the southeastern US. USDA provides R factor maps and values by location.

What is the K factor (soil erodibility)?

The K factor measures how susceptible a soil is to erosion by water. It ranges from 0.02 for very resistant soils (coarse sands) to 0.69 for highly erodible silty loam soils. K values are determined from soil texture, organic matter, structure, and permeability.

What are the LS, C, and P factors?

LS is the slope length-gradient factor (steeper and longer slopes increase erosion). C is the cover-management factor (bare soil = 1.0; dense cover = near 0). P is the support practice factor (terracing, contouring; no practice = 1.0, best practice approaches 0.1).

Is USLE the same as RUSLE?

The Revised Universal Soil Loss Equation (RUSLE) is an updated version published by the USDA in 1997 with improved factor estimation methods. The same A = R x K x LS x C x P equation structure applies. RUSLE is preferred for most current applications.

Official sources

USDA Agricultural Research Service: RUSLE2 Documentation.
USDA NRCS: NRCS Technical Tools.
Wischmeier, W.H. and Smith, D.D. (1978), USDA Agricultural Handbook No. 537: Predicting Rainfall Erosion Losses.

Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.