Tools you might need next
Calculate optimal seed spacing, plants per row, and rows per bed for vegetable garden planning and efficient seed placement.
Calculate cubic feet and cubic yards of soil mix needed to fill your raised garden beds from length, width, and fill depth.
Calculate carbon-to-nitrogen ratio for compost piles using brown and green material weights to balance decomposition speed.
The three numbers show percent by weight of nitrogen (N), phosphorus (P₂O₅), and potassium (K₂O) in the bag.
nutrient lbs = fertilizer lbs × (NPK percent / 100)Divide total fertilizer needed by bed or lawn area to get rate per square foot, then scale to your space.
Start from a recommended nitrogen or phosphorus rate for your crop, then solve for how much of your specific blend to apply.
Updated: July 2026
Calculate how much 10-10-10 to spread on a 100 sq ft bed without exceeding nitrogen limits for leafy crops.
See which 15-0-15 or 24-0-8 product delivers your target nitrogen with less total material.
Convert a pounds-per-100-feet recommendation into per-square-foot rate for raised rows.
Fertilizer rates are based on weight and NPK percent. A scoop of pellet and a scoop of granular blend can differ greatly.
Rate is per unit area. Double the square footage means double total product, not double the percent on the label.
Translate bag labels into actual pounds or ounces per area. Enter NPK numbers, target nutrient rate, and bed size to get a practical application amount.