Calculate planting population, seed spacing, and sacks to order for corn, soybeans, dry beans, wheat, sunflowers, and other row crops. The Potato Seed tab handles seed piece weight, chip loss, and full cost estimation. Fully reversible — enter population to calculate spacing, or enter spacing to calculate population.
Calculate planting population, seed spacing, and the number of seed bags needed to order for any field size. Supports corn, soybeans, wheat, canola, and other row and small-grain crops. Enter your target seeds per acre, expected germination rate, row spacing, and field size — get seeds per foot of row, bags required, and total seed cost. Useful for seed ordering, planting population audits, and agronomic planning. Works in acres and hectares.
Population ↔ spacing ↔ sacks to order. Switch tabs for grain seed or potato seed.
Fill in the fields to see your results.
📊 Related calculators: Fertilizer Rate — calculate starter fertilizer rates alongside your seeding pass. | GDD Tracker — track heat unit accumulation from your planting date automatically. | Crop Yield — project revenue at expected yield and price.
Seeding rate is the number of seeds planted per unit of land area — typically expressed as seeds per acre or seeds per hectare. It's distinct from the seed bag label's "seeds per pound" or "seeds per unit." The optimal seeding rate depends on the crop, target plant population, expected germination rate, and row spacing. Planting too few seeds reduces yield; planting too many wastes seed cost without yield benefit. This calculator converts between seeding rate, field size, and the number of seed bags needed to order.
Seeds per acre = (lbs/acre seed rate × seeds/lb). For corn at 34,000 plants/acre with 94% germination, you need 34,000 ÷ 0.94 = 36,170 seeds/acre. At 80,000 seeds/unit, that is 36,170 ÷ 80,000 = 0.452 units/acre. The seed rate calculator handles this conversion automatically for corn, soybeans, wheat, and other crops.
Corn seeding rates typically run 30,000–36,000 seeds/acre for dryland and 32,000–38,000 seeds/acre for irrigated production, adjusted for hybrid, soil, and irrigation capability. Higher plant populations (38,000+) are sometimes used on high-yield irrigated ground but require careful hybrid selection to avoid barrenness and stalk rot.
CWT of seed potato per acre depends on your target plant population, in-row spacing, and seed piece weight. As a general rule, russet varieties in the Columbia Basin planted at 34-inch rows and 9–11 inch in-row spacing with 2.0 oz seed pieces require approximately 18–22 CWT (1,800–2,200 lbs) of seed per acre. Use the Potato Seed tab above: enter your row spacing, in-row spacing, and seed piece weight — the calculator shows total pounds, CWT, and number of 100-lb sacks needed for your acreage.
The standard seed piece weight for Russet Burbank is 1.5–2.5 oz per piece, with 2.0 oz being the most common target in Columbia Basin production. Seed pieces should have at least one eye each. Pieces under 1.5 oz tend to produce weaker plants; pieces over 3.0 oz add unnecessary seed cost without proportional yield benefit. For certified seed, whole tubers are typically sized at 3–4 oz (A-size seed), 4–6 oz (B-size), or 6–8 oz (C-size) before cutting.
Multiply your total pounds of seed needed by the number of acres, then divide by 50. For example: 34-inch rows, 10-inch in-row spacing, 2.0 oz seed pieces, 100 acres. Plants per acre = (43,560 sq ft/ac) ÷ (2.83 ft row spacing × 0.833 ft in-row spacing) = 18,484 plants/ac. Total seed weight = 18,484 × 2.0 oz ÷ 16 oz/lb = 2,311 lbs/ac × 100 ac = 231,100 lbs ÷ 50 = 4,622 sacks. The Potato Seed tab calculates this automatically — enter your spacing, seed piece weight, and acres.