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USLE — Soil Loss Calculator

Enter the five USLE factors and get the predicted average annual soil loss in tons per acre per year, plus the metric equivalent in tonnes per hectare. Sheet and rill erosion only — see Topic 17 for what each factor means.

A = R · K · LS · C · P

R	rainfall–runoff erosivity factor
K	soil erodibility factor
LS	slope length/steepness factor
C	cover-management factor (0–1)
P	support-practice factor (0–1)

R — erosivity K — erodibility LS — topography C — cover (0–1) P — practice (0–1)

For study and checking only. These calculators run entirely in your browser — nothing is sent anywhere. They are meant to verify your hand calculations while you study; on the exam you will work by hand with the NCEES reference handbook. The interpretation bands below are rough study guidance, not a regulatory standard.

Worked example: USLE on a construction site

A construction site has R = 250, K = 0.32, LS = 1.4. With straw mulch and contouring: C = 0.10, P = 0.75. Without controls: C = 1.0, P = 1.0.

With controls: A = 250 × 0.32 × 1.4 × 0.10 × 0.75 = 8.4 tons/acre/yr (≈ 18.8 tonnes/ha/yr)
Without controls: A = 250 × 0.32 × 1.4 = 112 tons/acre/yr
The two management factors (C and P) cut predicted loss by a factor of 112/8.4 ≈ 13 — exactly what C and P are for

Exam tip: the USLE estimates sheet and rill erosion only — gully, streambank, and wind erosion are outside it.

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Preparing for exam day? The 110-question FE Civil practice exam is a full 5-hour-20-minute rehearsal with detailed solutions.