Two-Peg Test Calculator
Computes level collimation error from two-peg test readings for instrument calibration.
Enter Values
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
- Enter the two midpoint staff readings (A and B).
- Enter the two near-end staff readings (A and B).
- Press Calculate for the collimation error.
How it works
From the midpoint the readings are error-free, giving the true height difference. The reading from one end reveals the collimation error — a large error means the level needs adjusting.
Worked example
Standard two-peg test. Reports the collimation error in millimetres over the peg spacing.
Frequently asked questions
How much collimation error is acceptable?
A few millimetres over the test distance is usually fine; beyond that, adjust the instrument or send it for service.
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Cite this tool
Zerdly. (2026). Two-Peg Test Calculator. Retrieved from https://www.zerdly.com/tools/two-peg-test-calculator/
Tip: Enter any known values to calculate the remaining results.
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