Weighted Average RL Calculator
Computes a weighted mean reduced level from levelling observations and their assigned weights.
Reduced levels & weights
| Reduced level (m) | Weight | |
|---|---|---|
Weights are usually the number of observations, or the inverse of each value’s variance. Runs in your browser.
Result
Weighted mean = Σ(weight × RL) ÷ Σweight. It pulls toward the readings you trust most (highest weight).
How to use this calculator
- Enter each reduced level and its weight (e.g. the number of observations behind it).
- Add or remove rows to match your readings.
- Read the weighted mean, with the simple mean for comparison.
How it works
A weighted mean trusts some readings more than others: weighted mean = Σ(weight × RL) ÷ Σweight. Weights are usually the number of observations, or the inverse of each value's variance (more precise readings get more weight).
The simple mean treats every reading equally. When the weights differ, the two means diverge — the weighted mean is pulled toward the higher-weighted values.
Worked example
RL 10.0 (weight 3) and 11.0 (weight 1). Weighted mean = (3×10.0 + 1×11.0) ÷ 4 = 10.25, while the simple mean is 10.5 — the weighted result sits closer to the more-observed value.
Frequently asked questions
What should I use as the weight?
Most often the number of observations that produced each reading, or the inverse of its variance (1/σ²). A reading you trust twice as much gets twice the weight.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
Related tools
- Repeated Observation Mean and Spread Calculator
- Standard Error of the Mean Calculator
- Bearing Mean Circular Statistics Calculator
- Closed Level Loop Adjustment Allocator
- Height of Collimation Worksheet
- Rise and Fall Levelling Worksheet
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Cite this tool
Zerdly. (2026). Weighted Average RL Calculator. Retrieved from https://www.zerdly.com/tools/weighted-average-rl-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.