Reduced Level From Staff Reading Calculator

Work out reduced level from staff reading instantly with clear inputs, formula shown and shareable results.

About Reduced Level From Staff Reading Calculator

With the height of collimation known, every reduced level is simply that height less the staff reading. Comparing the result with the design level gives the cut or fill, and the staff reading that would indicate exactly design level is the height of collimation less the design level, which is the number the setting-out crew actually works to.

Formulas

Reduced level

RL = height of collimation - staff reading

Setting out

Target staff reading = height of collimation - design level

Worked example

With the default values below, Reduced Level From Staff Reading Calculator returns Reduced level of the point of 99.3600. Change any input above and every figure here is recalculated in your browser.

Inputs used

Height of collimation: 101.235 m
Staff readingminimum 0 m: 1.875 m
Design level at the point: 99.5 m

Results

Reduced level of the point: 99.3600 m
Cut or fill against the design level: -0.1400 m
Staff reading for the design level: 1.7350 m
Instruction to the operator: Fill 140 mm

Step by step

1Values used
2Reduced level
3Setting out
4Reduced level of the point= 99.3600 m
5Cut or fill against the design level= -0.1400 m
6Staff reading for the design level= 1.7350 m
7Instruction to the operator= Fill 140 mm

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Reduced Level From Staff Reading figure worked out?

RL = height of collimation - staff reading. With the height of collimation known, every reduced level is simply that height less the staff reading.

Why work to a target staff reading?

It removes arithmetic from the field. The operator raises or lowers the surface until the staff reads the target, with no calculation per point and therefore no mistakes.

What values do I need to enter?

This calculator takes 3 inputs: Height of collimation, Staff reading, Design level at the point. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.