Why dollars per ton mislead
Fertilizer is bought by the ton. That unit is a poor way to compare products that do not carry the same nutrients. A cheaper ton can be the expensive source once you count how many pounds of nitrogen, phosphate, potash, or sulfur are actually in it. Cost per pound of nutrient puts those products on one scale, which is the comparison that matters on a prepay sheet and at the counter.
The arithmetic is short, and the calculator above does it as you type. A ton is 2,000 pounds. The guaranteed analysis is a percent by weight. Pounds of a nutrient in a ton equal 2,000 times that percent divided by 100. Cost per pound equals the price per ton divided by those pounds. If a product is $500 a ton and 25 percent of its weight is nitrogen, a ton holds 500 pounds of nitrogen and the nitrogen costs $1.00 per pound. Change the price or the analysis and the cost per pound moves in a straight line. Use the button on the calculator if you want to see that example filled in.
Nitrogen, phosphate, potash, and sulfur
Enter the price per ton and the analysis on the label or the invoice. The same formula prices P₂O₅, K₂O, and sulfur. Leave a nutrient blank, or enter zero, when the product does not contain it. Compare straight goods on the cost per pound of the nutrient you are actually buying.
Write the price you would actually pay, with freight treated the same way on every product. Sulfur is easy to leave off a comparison and then pay for as a separate pass. Price it per pound the same way you price nitrogen, phosphate, and potash.
What this number does not do
Read the result with one limit in mind. The calculator assigns the full price per ton to each nutrient you enter. That is the right reading for a product that is basically one nutrient. When a product carries two nutrients, each line still uses the full ton price. You cannot add those lines together, and you should not treat either one as the only cost of that nutrient. A phosphate product that also contains nitrogen is the usual case. Part of the ton is paying for the nitrogen, and the rest is paying for the phosphate.
Splitting that fairly means crediting the nitrogen at the price of a straight nitrogen source, then charging what is left to the phosphate. FertCalc Pro does that residual split inside a blend, using the products and prices you actually apply. This page does not. It is the quick screen for straight goods. The fertilizer blend calculator is the full screen, once your desired analysis needs more than one product and you want the lowest-cost way to hit it.
A cost per pound does not tell you how much to apply. Rate still comes from the crop, the field, and the recommendation you will stand behind. Check the label against the invoice before a large booking. Rounding a percent will move the cost per pound enough to flip which product looks cheaper.
From one product to a blend sheet
Once you know the straight-goods prices, the next decision is usually a blend. Your desired analysis may call for nitrogen, phosphate, potash, and sulfur together. Several mixes can hit that analysis. The lowest-cost mix depends on the prices that day, including products that carry more than one nutrient. The blend calculator takes your desired analysis, your acres, and your product prices and returns rates, a cost per acre, and a quote.
From the same rates you can print a blend sheet. You set the desired number of batches. Batches are 15,000 lb or less, with a scale reading the plant can follow and a tonnage total for the order. The dry fertilizer blend sheet page describes that loading sequence. Liquid products use the same analysis language, percent by weight, but many of them are bought and applied by the gallon. To put a liquid on this calculator, start from a price per ton, or convert a price per gallon with the product's pounds per gallon: price per ton equals price per gallon divided by pounds per gallon, times 2,000. If a liquid is $3.30 a gallon and weighs 11 pounds per gallon, the price per ton is $600. The liquid fertilizer blend calculator is the page to use when the whole mix is liquid and the ticket has to be in gallons.
Use the blend tool when your desired analysis needs more than one product. The 14-day free trial needs no card. Add a card before it ends to keep going at $24.99 a month or $274.99 a year.