If you know current pH and target pH, you can still get a working estimate even when soil type is uncertain.
Soil pH Lime Calculator (Current pH to Target pH by Soil Type)
Estimate a practical lime application range from current pH, target pH, and soil type.
This is a quick estimate for cases where a full soil test is not available. Treat the result as a range and use it to avoid over-application, not as an exact prescription.
Works with the shortest three inputs
Shows kg/10a, kg/ha, t/ha, and lb/acre together
Adjusts for till depth and neutralizing value
Supports copy, share URL, and recent restores
What This Tool Shows
The main result is always a range, not a single point, so the uncertainty stays visible.
You can adapt the result for dolomitic lime, hydrated lime, or other materials by entering the neutralizing value on the bag label.
How to Use
- Enter current pH and target pH.
- Choose a soil type. If you are unsure, you can leave it on “Unknown.”
- Open advanced settings only if you want to refine texture, till depth, material type, or neutralizing value.
- Review the range, unit conversions, breakdown, and short notes in the result panel.
- Reuse the same condition with result copy, share URL, or recent calculations.
Examples
Loam, mixed to 15 cm, from pH 5.5 to 6.0
Input
Current pH 5.5, target pH 6.0, soil type Loam, depth 15 cm, material Calcitic lime, neutralizing value 100%
Output
1.3-1.9 t/ha, 127-191 kg/10a, 1,270-1,905 kg/ha, 1,133-1,700 lb/acre
Clay-heavy soil, mixed to 20 cm, from pH 5.2 to 6.5
Input
Current pH 5.2, target pH 6.5, soil type Clay-heavy, depth 20 cm, material Dolomitic lime, neutralizing value 80%
Output
7.1-10.7 t/ha, 715-1,072 kg/10a, 7,149-10,723 kg/ha, 6,378-9,567 lb/acre
Basis and Assumptions
- Soil pH alone does not tell you the buffering capacity, so this tool returns a range instead of a point estimate.
- The base requirement is estimated from texture-based coefficients and a two-band interpolation split at pH 5.5.
- A deeper incorporation depth increases the requirement, and a lower neutralizing value increases the required amount.
- The “Unknown” option uses an average mineral-soil coefficient and a wider uncertainty band.
Glossary
Neutralizing value (CCE/ECCE)
This is the acid-neutralizing strength relative to pure CaCO3 = 100. ECCE also reflects fineness and practical reactivity.
Till depth
This is the depth at which the material will be incorporated. A deeper layer requires more amendment.
Buffering capacity
This is how strongly the soil resists pH change. It is influenced by CEC, organic matter, and clay minerals.
CaCO3 basis
This means the requirement is expressed as an equivalent amount of calcium carbonate so different lime materials can be compared.
Formulas
Base = coeff_low × ΔpH_low + coeff_high × ΔpH_highDepthAdjusted = Base × (depth cm / 18)Adjusted = DepthAdjusted × (100 / neutralizing value %)Min = Adjusted × (1 - uncertainty)Max = Adjusted × (1 + uncertainty)
Frequently Asked Questions
I only know the pH value and do not have a full soil test.
You can still calculate a quick estimate, but pH alone does not show buffering capacity. Use this result as a starting draft and rely on a soil test with buffer pH or lime requirement if you can get one.
Can I use this for dolomitic lime or hydrated lime?
Yes. Pick the material type to load a reasonable starting neutralizing value, then adjust the value to match the bag label if needed.
Which units are included?
The result always shows kg/10a, kg/ha, t/ha, and lb/acre. The primary display can switch between Metric and US.
What happens if the target pH is lower than the current pH?
The tool shows “No lime needed.” If you need to lower pH, you should consider sulfur or another acidifying amendment instead.
Is it okay to choose “Unknown” for soil type?
Yes. The calculator uses an average coefficient and a wider uncertainty band. If you know the detailed texture later, you can override it in advanced settings.
Notes
- This is a simplified estimate from soil pH and soil type. The actual requirement can change substantially with CEC, organic matter, and clay mineralogy.
- If possible, prioritize a soil test that includes buffer pH or lime requirement.
- After application, incorporate the material and retest the soil to confirm progress toward the target pH.
- The best target pH depends on crop, region, and field condition, so consult a local advisor when needed.