How to use the HI calculator?

Input RL and BS to get HI automatically. Then enter FS to get RL. Add rows as needed and export to CSV.

Height of Instrument (HI) Calculator

📐 Height of Instrument (HI) Calculator

Q: What is Height of Instrument (HI) in surveying?

Height of Instrument (HI) is calculated using the formula HI = RL + BS.

Q: How to calculate Reduced Level (RL)?

Reduced Level (RL) is calculated using RL = HI − FS.

Q: What do BS, IS, and FS mean?

BS is Backsight, IS is Intermediate Sight, and FS is Foresight.

Station	Distance	BS	IS	FS	HI	RL	Remarks	Action

Σ BS = 0

Σ FS = 0

🔍 Height of Instrument (HI) Calculator — FAQ

What is Height of Instrument (HI) in surveying?

Height of Instrument (HI) refers to the elevation of the line of sight of the leveling instrument.

Formula: HI = RL + BS

How to calculate Reduced Level (RL)?

After calculating HI, you can get the RL using:

RL = HI − FS

What do BS, IS, and FS mean?

BS (Backsight): Reading on a known RL point.
IS (Intermediate Sight): Readings on details where RL is needed.
FS (Foresight): Reading taken before shifting the instrument.

How to use this HI Calculator?

1. Enter a known RL in the first row.
2. Enter BS → HI calculates automatically.
3. Enter IS/FS → RL updates automatically.
4. Add more rows for each instrument shift or station.
5. Export data using the CSV button.

Example Calculation

Given:
RL = 520.50
BS = 0.585

HI = 520.50 + 0.585 = 521.085

If FS = 1.234
New RL = 521.085 − 1.234 = 519.851