Soil Moisture Converter

🌱 Volumetric to gravimetric moisture, saturation percent, and related soil units—free and instant. For irrigation, agronomy, geoscience, and environmental monitoring. No sign-up required.

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Common Conversions
Quick access to frequently used conversions
Unit Information

Scientific Units

Scientific and technical measurements

θv
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Volumetric Moisture Content
Volume of water per unit volume of soil (m³/m³)
%
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Volumetric Moisture (%)
Volumetric moisture content as percentage
cm³/cm³
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cm³/cm³
Cubic centimeters of water per cubic centimeter of soil
mm/m
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mm/m
Millimeters of water per meter of soil depth
in/ft
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inch/ft
Inches of water per foot of soil depth
θg
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Gravimetric Moisture Content
Mass of water per unit mass of dry soil (kg/kg)
%
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Gravimetric Moisture (%)
Gravimetric moisture content as percentage
g/g
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g/g
Grams of water per gram of dry soil
lb/lb
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lb/lb
Pounds of water per pound of dry soil
S%
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Saturation (%)
Degree of saturation as percentage of total pore space
S
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Saturation (decimal)
Degree of saturation as decimal (0 to 1)
mm
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Water Depth (mm)
Depth of water in millimeters
cm
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Water Depth (cm)
Depth of water in centimeters
in
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Water Depth (inch)
Depth of water in inches
FC
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Field Capacity
Soil moisture content at field capacity (volumetric)
WP
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Wilting Point
Soil moisture content at permanent wilting point (volumetric)
AW
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Available Water
Available water capacity (field capacity - wilting point)
Preferences

Understanding soil moisture

Soil moisture describes how much water is held in the soil. Farmers, hydrologists, and environmental scientists measure it in different ways; this page helps you translate between those measurements.

Volumetric water content answers: "What fraction of a chunk of soil is water by volume?" Think of it as how full the soil pores are with water, expressed per unit volume of soil. Field sensors and irrigation models often use this view.

Gravimetric moisture answers: "How much water mass compared to the mass of dry soil?" Labs often dry a soil sample and weigh it before and after to get this ratio—useful when you care about mass balance or chemistry.

Saturation compares current moisture to the maximum the soil could hold when all pores are full of water. It is useful for knowing how close soil is to being waterlogged or how much room is left to absorb rain.

The converter and the technical section below use standard symbols (for example volumetric and gravimetric ratios) so you can match textbooks and data sheets after you read the ideas here.

Common Soil Moisture Conversions

Agriculture

Convert between different soil moisture measurement methods for crop irrigation planning and soil health assessment.

Geoscience

Analyze soil moisture data for hydrological studies, climate research, and environmental monitoring applications.

Soil Science

Convert between laboratory and field measurements for comprehensive soil moisture analysis and research.

Soil Moisture Unit Categories

Volumetric Units

Volume of water per unit volume of soil, most commonly used in field measurements.

  • • θv (m³/m³) - standard volumetric
  • • % - volumetric percentage
  • • cm³/cm³ - cubic centimeters
  • • mm/m - depth-based volumetric
  • • in/ft - imperial depth-based

Gravimetric Units

Mass of water per unit mass of dry soil, commonly used in laboratory analysis.

  • • θg (kg/kg) - standard gravimetric
  • • % - gravimetric percentage
  • • g/g - grams per gram
  • • lb/lb - pounds per pound
  • • Laboratory standard method

Saturation & Depth Units

Degree of saturation and depth-based water measurements for practical applications.

  • • S% - saturation percentage
  • • S - saturation decimal (0-1)
  • • mm, cm, in - water depth
  • • FC - field capacity
  • • WP - wilting point

Technical Information

Unit Relationships

Understanding the relationships between different soil moisture measurement methods is crucial for accurate soil analysis and agricultural planning.

Key Conversion Factors:

  • • θv = θg × ρb/ρw (volumetric to gravimetric)
  • • θg = θv × ρw/ρb (gravimetric to volumetric)
  • • ρb = bulk density of soil (g/cm³)
  • • ρw = density of water (1 g/cm³)
  • • S = θv/θs (saturation ratio)
  • • θs = total porosity of soil

Practical Applications

Soil moisture measurements are fundamental to understanding soil-water relationships and optimizing agricultural practices.

Common Reference Values:

  • • Field Capacity: 0.25-0.35 m³/m³ (sandy soils)
  • • Field Capacity: 0.35-0.45 m³/m³ (clay soils)
  • • Wilting Point: 0.05-0.15 m³/m³ (sandy soils)
  • • Wilting Point: 0.15-0.25 m³/m³ (clay soils)
  • • Available Water: 0.15-0.25 m³/m³ (most soils)
  • • Saturation: 0.40-0.60 m³/m³ (total porosity)