Zerdly

Batter Ratio Calculator

Convert a batter ratio written as nH:1V into the slope angle, and get the horizontal run, setback and sloping face length for a given vertical height. A batter-design tool for earthworks, cut/fill slopes, embankments and drains.

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How to use this calculator

Enter Values

Enter your values and press Calculate to see results.

Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.

How to use this calculator

  1. Enter the batter ratio as n — the horizontal metres per 1 metre vertical (e.g. 1.5 for 1.5H:1V).
  2. Enter the vertical height Hv of the batter in metres.
  3. Read the slope angle, horizontal run/setback, batter face length and grade.

How it works

A batter ratio nH:1V means the slope runs n metres horizontally for every 1 metre of rise. The slope angle from horizontal is atan(1/n), and the grade is 100/n percent.

Over a vertical height Hv the batter sets back a horizontal distance of n·Hv, and the sloping face measures Hv·√(1+n²). A larger n gives a flatter, more stable batter with a bigger footprint.

Worked example

A 1.5H:1V batter, 4 m high. Slope angle = atan(1/1.5) = 33.7°. Horizontal run/setback = 1.5×4 = 6 m. Face length = 4×√(1+1.5²) = 7.21 m. Grade = 100/1.5 = 66.7%.

Common mistakes

  • Writing the ratio the wrong way round — nH:1V is horizontal-to-vertical, so n is the horizontal number.
  • Confusing grade (100/n %) with the slope angle in degrees (atan(1/n)).
  • Using the sloping face length where the horizontal setback is needed for pegging out.

Frequently asked questions

What does 1.5H:1V mean?

1.5 metres horizontal for every 1 metre vertical. That is a slope angle of atan(1/1.5) ≈ 33.7° and a grade of about 66.7%.

How do I convert a batter ratio to an angle?

Slope angle from horizontal = atan(1/n) where n is the horizontal-per-vertical figure. A 2H:1V batter is atan(1/2) ≈ 26.6°.

How is this different from the Grade & Fall Calculator?

The Grade & Fall Calculator converts between grade, ratio and angle. This tool adds the design outputs — horizontal run, setback and sloping face length for a chosen height.

What is the face length of a batter?

The length measured up the sloping face: Hv·√(1+n²). For a 4 m high 1.5H:1V batter it is about 7.21 m.

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