Geothermal Borehole Depth Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 28, 2026Geothermal Borehole Depth Calculator
Planning a ground-source geothermal heat pump installation? This calculator estimates the borehole depth needed to meet your heating capacity requirement.
Required Depth (m) = Required Capacity(W) / Heat Extraction Rate(W per meter)
Example
A 10 kW heating capacity requirement, 50 W per meter extraction rate:
Required Capacity = 10,000 W → ~200 meters of borehole depth needed
Why the Extraction Rate Reference Is Just a Starting Point
Heat extraction rate per meter of borehole varies significantly with local soil and rock thermal conductivity - moist clay soil, for instance, conducts heat quite differently than dry sandy soil or solid bedrock, all of which affects the real achievable extraction rate at a specific site.
A Professional Site Survey Is Essential
A professional geological survey and thermal conductivity test at the specific installation site gives a far more accurate depth requirement than this general reference rate - actual system design should always be based on that site-specific data before drilling begins.