I've a fertilizer that has this as NPK specification

NPK 6,1-4-5,6

I've understood till now the number should be three, one for each component NPK, what the other numbers means there? Here below the label. enter image description here

  • The first 6 is for Nitrogen, and the last 6 for Kalium (Potassium). The three numbers in the center are for Phosphorus and probably Calcium and Magnesium, but we will need a photo of the label to be sure.
    – Gyrfalcon
    Commented Aug 28, 2022 at 16:08
  • What make is the product? NPK should just show Nitrogen, Phosphorus and Potassium, ie, 3 figures as you say- any other ingredients are usually listed separately, so not sure what that means, though a photo of the total ingredients might help
    – Bamboo
    Commented Aug 28, 2022 at 16:47

1 Answer 1


Probably using the , for decimal point. Common in some parts of the world, uncommon in others. So still just 3 numbers, but more precise:

6.1 - 4.0 - 5.6

  • That could make sense becaouse actually in my part of the world decimal separator is comma ( generally speaking, we expect to find . without too many surprise ) the formatting in the label is, if you are right, a little confusing btw. Commented Aug 28, 2022 at 17:25
  • 1
    While 6,1 - 4,0 - 5,6 would certainly be clearer than 6,1-4-5,6, few companies bother to employ people who will consider such subtleties. So they got the data on the label, and called it a day.
    – Ecnerwal
    Commented Aug 28, 2022 at 19:15
  • 1
    If you look at the detailed list of ingredients, there are four sources of nitrogen, contributing 0.5%, 1.6%, 1.6%, and 2.4%, respectively, for total nitrogen of 6.1%, which means the "probably" in the answer should be "definitely". The detailed list likewise shows phosphorus pentoxide (P₂O₅) at 4% and potassium oxide (K₂O) at 5.6%.
    – njuffa
    Commented Aug 29, 2022 at 1:40

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