Two-Peg Test Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserIntermediate
Enter Values
Enter your values and press Calculate to see results.
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.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.