Convert K to K₂O


What is K?

  • K stands for Potassium, an important nutrient for plants. It helps with water regulation, disease resistance, and overall growth.

What is K₂O?

  • K₂O (potassium oxide) is the form of potassium usually mentioned on fertilizer labels. It’s a standard way to express the amount of potassium in fertilizers.

Why convert K to K₂O?

  • When you test soil or plant tissue, potassium content is often given as elemental K.
  • Fertilizers show potassium content as K₂O.
  • To figure out how much fertilizer to apply based on potassium needs, you need to convert K (elemental) into K₂O.

Conversion factor:

  • Molecular weight of K = 39.1
  • Molecular weight of K₂O = (2 × 39.1) + 16 = 94.2

Formula:

K₂O=K×1.204

How to use the calculator:

  1. Enter the amount of potassium (K) from your soil test or recommendation.
  2. The calculator multiplies it by 1.204.
  3. The result is the amount of potassium expressed as K₂O, which you can compare directly to fertilizer labels.

Example:

  • If your soil test shows 100 kg/ha of K:

    K₂O=100×1.204=120.4 kg/ha

  • So, you need fertilizer that provides about 120.4 kg/ha of K₂O to meet the potassium requirement.

You can find more agriculture conversion calculators here.