What This Calculator Does Calculates seed quantity based on your field area in acres or hectares Adjusts for seed germination percentage so low-viability seed is never underestimated Adjusts for seed purity so inert material and non-seed content are accounted for Estimates total bags of seed needed for any field size Works for hybrid maize, OPV
What This Calculator Does
- Calculates seed quantity based on your field area in acres or hectares
- Adjusts for seed germination percentage so low-viability seed is never underestimated
- Adjusts for seed purity so inert material and non-seed content are accounted for
- Estimates total bags of seed needed for any field size
Works for hybrid maize, OPV maize, sweet corn, and fodder varieties
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About This Seed Rate Calculator
The Seed Rate Calculator helps farmers and growers determine exactly how much seed is needed for a given field area. It accounts for the crop’s standard seeding rate, your actual field size, germination percentage, and seed purity — preventing costly over-seeding or poor stands from under-seeding. Accurate seed rate planning is one of the highest-return inputs in crop establishment.
Formula Used
Seed Required = (Field Area × Standard Seeding Rate) ÷ (Germination% ÷ 100) ÷ (Purity% ÷ 100). When germination and purity are not entered, they default to 100%, giving the base agronomic rate for the chosen crop.
Usage Tip
Always verify the germination percentage on your seed bag certificate — even certified seed can vary by 5–10%, which meaningfully affects final plant populations on large fields.
Most farmers only need three numbers to estimate maize seed requirements accurately: field area, germination percentage, and seed purity percentage. This maize seed rate calculator guide covers the formula, worked examples, seed count tables, bag quantity estimates, regional considerations, and the cost math that rarely appears in standard seed guides.
Quick Answer
| Question | Answer |
| Standard maize seed rate | 8–10 kg per acre |
| 1 acre seed requirement | ~9 kg (certified hybrid) |
| 1 hectare seed requirement | 20–25 kg |
| Target plant population | 27,000–33,000 plants per acre |
| Typical 10 kg bags needed | 1 bag per acre (certified seed) |
Key Takeaways
Germination below 90% requires noticeably more seed per acre
Purity below 98% increases seed requirement even with good germination
One kg of hybrid maize seed contains roughly 2,200 to 3,500 seeds (depends on TKW)
Farm-saved hybrid seed typically requires 20 to 30% more seed per acre than certified
What Is the Recommended Maize Seed Rate Per Acre?
For hybrid maize under standard field conditions, 8 to 10 kg per acre is the established recommendation. That assumes certified seed with at least 90% germination and 97% or higher purity, planted at 75 x 25 cm or 60 x 25 cm spacing.
Open-pollinated varieties (OPVs) typically run 10 to 12 kg per acre. Baby corn and fodder maize are intentional outliers at 20 to 30 kg per acre because dense planting is the production goal for those types.
| Maize Type | Seed Rate / Acre | Target Plants / Acre |
| Hybrid (single-cross) | 8–10 kg | 27,000–33,000 |
| Hybrid (double-cross) | 9–11 kg | 25,000–30,000 |
| High-density hybrid | 10–12 kg | 33,000–40,000 |
| Open-Pollinated (OPV) | 10–12 kg | 25,000–30,000 |
| Sweet Corn | 8–10 kg | 20,000–25,000 |
| Baby Corn | 20–25 kg | 80,000–100,000 |
| Fodder / Silage | 25–30 kg | 100,000+ |
Maize Seed Rate Calculator Formula
Farmers usually buy seed by weight, but crop establishment depends on the number of viable seeds that actually germinate. The formula bridges those two realities.
Formula: Adjusted Seed Rate (kg/acre) = Base Seed Rate / (Germination% x Purity%)
Example: Base rate 8 kg, germination 90%, purity 98% = 8 / (0.90 x 0.98) = 9.07 kg per acre
Total field requirement: Adjusted rate x total acres. Always add 5 to 10% buffer for end rows, replanting gaps, and handling loss.
Use the same formula for a maize seed requirement calculator, corn seed rate calculator, or maize population calculator — the inputs and logic are identical regardless of what the tool is called.
Calculator Example Scenarios
Example 1: 1 Acre, 95% Germination, 99% Purity (Certified Hybrid)
8 / (0.95 x 0.99) = 8 / 0.9405 = 8.51 kg. Round up to 9 kg. One standard 10 kg bag covers this with buffer.
Example 2: 5 Acres, 85% Germination, 97% Purity (Stored Certified Seed)
8 / (0.85 x 0.97) = 8 / 0.8245 = 9.7 kg per acre x 5 acres = 48.5 kg. Buy five 10 kg bags plus one extra bag as buffer = 6 bags total.
Example 3: 10 Acres, Farm-Saved Seed at 82% Germination, 92% Purity
8 / (0.82 x 0.92) = 8 / 0.7544 = 10.6 kg per acre x 10 acres = 106 kg. Buy eleven 10 kg bags. Farm-saved seed typically needs 25% more than certified.
Example 4: 2 Acres, High-Density Planting, 93% Germination, 98% Purity
10 / (0.93 x 0.98) = 10 / 0.9114 = 10.97 kg per acre x 2 acres = 21.9 kg. Two 10 kg bags plus one 5 kg bag.
How Many Bags of Maize Seed Are Required Per Acre?
For certified hybrid seed, one 10 kg bag is usually enough for one acre. For stored or farm-saved seed, an extra bag may be required depending on germination and purity test results. Always confirm before buying.
| Bag Size | Seed Rate / Acre (Standard) | Bags Needed / Acre |
| 5 kg bag | ~9 kg | 2 bags (with buffer) |
| 10 kg bag | ~9 kg | 1 bag (certified seed) |
| 20 kg bag | ~9 kg | 0.5 bag (covers 2 acres) |
| 25 kg bag | ~9 kg | 1 bag covers ~2.5 acres |
| Field Size | Seed Required | 10 kg Bags Needed |
| 0.5 acre | ~4.5 kg | 1 bag |
| 1 acre | ~9 kg | 1 bag (certified) / 2 bags (farm-saved) |
| 2 acres | ~18 kg | 2 bags |
| 5 acres | ~45 kg | 5 bags |
| 10 acres | ~90 kg | 9–10 bags |
| 20 acres | ~180 kg | 18–19 bags |
| 1 hectare | ~22 kg | 3 bags (10 kg) |
How Many Maize Seeds Are Needed Per Acre?
Farmers usually buy seed by weight, but crop establishment depends on the number of viable seeds placed in the ground. A kilogram of hybrid maize seed contains between 2,200 and 3,500 seeds depending on variety and Thousand-Kernel Weight (TKW).
Use a maize stand calculator or our Plant Population Calculator to cross-check your seeding rate against your target plant count before you start planting.
| TKW (g) | Seeds Per kg | Seeds in 10 kg Bag |
| 250 g | ~4,000 | ~40,000 |
| 280 g | ~3,570 | ~35,700 |
| 300 g | ~3,333 | ~33,330 |
| 320 g | ~3,125 | ~31,250 |
| 350 g | ~2,857 | ~28,570 |
SEO File Name
Target seeds per acre: To achieve 27,000 plants per acre at 90% germination and 98% purity, place about 30,700 seeds in the ground. At TKW 300 g, that requires roughly 9.2 kg of seed.
Maize Seed Rate Per Hectare
Many agricultural extension services and corn seed rate calculator guides publish recommendations in kg per hectare. One hectare equals 2.47 acres. To convert your per-acre rate, multiply by 2.47.
| Condition | Seed Rate / Hectare | Seed Rate / Acre |
| Irrigated hybrid | 20–22 kg | 8–9 kg |
| Rainfed hybrid | 22–25 kg | 9–10 kg |
| OPV / farm-saved | 25–30 kg | 10–12 kg |
| High-density hybrid | 25–30 kg | 10–12 kg |
| Fodder / Silage | 60–75 kg | 25–30 kg |
Maize Seed Rate for Rainfed vs Irrigated Conditions
The base formula is the same everywhere. What changes is the target plant population, because soil moisture availability directly limits how many plants a field can support through to grain fill.
Farmers can use our Irrigation Water Requirement Calculator to estimate crop water needs before deciding on planting density.
| Condition | Target Pop. / Acre | Seed Rate / Acre |
| Irrigated, fertile soil | 30,000–35,000 | 9–11 kg |
| Irrigated, average soil | 27,000–30,000 | 8–10 kg |
| Rainfed, high rainfall zone | 25,000–28,000 | 8–9 kg |
| Rainfed, semi-arid zone | 20,000–25,000 | 7–8 kg |
| Drought-prone zone | 18,000–22,000 | 6–7 kg |
CIMMYT research on tropical maize production consistently recommends 20,000 to 25,000 plants per acre for low-rainfall regions. Planting above this threshold under drought stress reduces yield instead of increasing it, because moisture competition between plants outweighs any population benefit.
Maize Seed Rate Recommendations by Region
Seed rate guidance from national extension services varies by climate zone. These are general benchmarks. Always verify with your local USDA Cooperative Extension Service or country-level agricultural ministry for the most accurate regional recommendation.
| Region / Climate | Seed Rate | Notes |
| Tropical (high rainfall) | 8–10 kg/acre | 60–75 x 25 cm spacing |
| Tropical (semi-arid) | 7–9 kg/acre | Lower population, wider spacing |
| Temperate (North America) | 8–10 kg/acre | USDA-aligned, varies by state |
| Sub-Saharan Africa | 9–12 kg/acre | Often OPV or farm-saved |
| South/Southeast Asia | 8–10 kg/acre | Mixed hybrid and OPV systems |
Maize Seed Rate for High-Density Planting
High-density planting targets populations above 33,000 plants per acre. Modern single-cross hybrids bred for this have narrow leaf architecture and strong stalks that tolerate closer spacing without significant lodging.
Standard varieties planted at high-density spacing produce smaller cobs and frequently yield less overall. High-density planting only makes agronomic sense with specifically adapted varieties, reliable irrigation, and high soil fertility.
| Density Level | Plants / Acre | Seed Rate / Acre | Requirement |
| Standard | 27,000–30,000 | 8–10 kg | Rainfed or irrigated |
| High density | 33,000–38,000 | 10–12 kg | Irrigated, fertile soil |
| Ultra-high density | 40,000+ | 12–15 kg | High-input irrigated only |
Maize Seed Rate by Maturity Group
| Maturity Group | Days to Maturity | Seed Rate / Acre | Spacing |
| Early | 80–100 days | 9–11 kg | 60 x 20 cm |
| Medium | 100–120 days | 8–10 kg | 60–75 x 25 cm |
| Late | 120–150 days | 7–9 kg | 75 x 25–30 cm |
Maize Seed Rate by Plant Spacing
For precise spacing-based calculations, use our Plant Spacing Calculator to model row and plant spacing combinations before planting.
| Row x Plant Spacing | Plants / Acre | Base Seed Rate (kg) |
| 60 cm x 20 cm | ~33,000 | 9–10 kg |
| 60 cm x 25 cm | ~26,600 | 8–9 kg |
| 75 cm x 20 cm | ~26,600 | 8–9 kg |
| 75 cm x 25 cm | ~21,300 | 7–8 kg |
| 75 cm x 30 cm | ~17,800 | 6–7 kg |
Maize Seed Rate Based on Germination Percentage
Many farmers blame patchy emergence on soil conditions or rain timing. In many of those cases, the seed was already testing at 80% germination when it went in. No seedbed preparation compensates for that.
A seed germination calculator helps you quickly test different germination scenarios before settling on a seed quantity. Every 5% drop in germination adds roughly 0.5 kg per acre to the requirement.
| Germination % | Seed Rate / Acre | Extra vs 95% |
| 95% | 8.6 kg | Baseline |
| 90% | 9.1 kg | +0.5 kg |
| 85% | 9.6 kg | +1.0 kg |
| 80% | 10.2 kg | +1.6 kg |
| 75% | 10.9 kg | +2.3 kg |
| 70% | 11.7 kg | +3.1 kg |
How Seed Purity Changes Maize Seed Requirement Per Acre
Seed purity is the percentage of genuine maize seed in a lot. The rest is inert material, weed seed, broken kernels, or other crop material. None of it produces a plant. You pay for it by weight when you buy and when you sow.
Practical impact: A bag at 95% purity versus 99% purity looks like a small gap. But at 9 kg per acre across 50 acres, that 4% difference leaves you nearly 18 kg short of viable seed if you buy equal total weight.
| Purity % | Actual Seed in 10 kg | Waste Per Bag |
| 99% | 9.9 kg | 0.1 kg |
| 97% | 9.7 kg | 0.3 kg |
| 95% | 9.5 kg | 0.5 kg |
| 90% | 9.0 kg | 1.0 kg |
| 85% | 8.5 kg | 1.5 kg |
Certified vs Farm-Saved Maize Seed: Which Requires More Seed Per Acre?
Certified hybrid seed costs more per kg but you need less of it. Farm-saved hybrid seed loses genetic performance in the second generation. Germination commonly drops to 75 to 85%. Purity is harder to verify without lab testing.
| Seed Type | Germination | Purity | Rate Adjustment |
| Certified hybrid | 90–95% | 97–99% | Base rate |
| Certified OPV | 88–92% | 96–98% | +5–8% |
| Farm-saved OPV | 80–88% | 90–95% | +15–20% |
| Farm-saved hybrid | 75–85% | 88–93% | +20–30% |
For OPV varieties, farm-saving is agronomically sound and the FAO actively supports seed-saving programs in smallholder farming regions. The critical step is running a germination test before every planting season and adjusting the maize seed quantity calculator result accordingly.
Maize Seed Cost Per Acre
Before buying fertilizer or arranging irrigation, many farmers first estimate how much seed the field will require. Certified hybrid seed in most markets runs $3 to $10 per kg. At 9 kg per acre that is $27 to $90 in seed cost alone.
The cheaper-seed calculation rarely works out. A $3/kg bag at 80% germination needs 10.5 kg per acre. A $5/kg bag at 95% germination needs only 8.6 kg per acre. At scale, the $5 seed costs less per established plant.
Use our Fertilizer Calculator alongside seed cost estimates to get a full input cost picture before finalizing your cropping plan.
| Seed Price / kg | Seed Needed / Acre | Seed Cost / Acre |
| $3/kg | 10.5 kg (80% germ) | ~$31.50 |
| $5/kg | 8.6 kg (95% germ) | ~$43.00 |
| $8/kg | 9 kg (90% germ) | ~$72.00 |
| $10/kg | 9 kg (90% germ) | ~$90.00 |
5 Factors That Can Increase or Reduce Your Maize Seed Rate
| Factor | Direction | Practical Impact |
| Low germination ( | Increase | Add 10–25% more seed |
| Low purity ( | Increase | Add 3–10% more seed |
| Precision planter (>95% accuracy) | Reduce | Save 5–10% vs manual |
| Heavy or crusted soil | Increase | Add 5–10% buffer |
| High TKW seed lot | Reduce kg (not seeds) | Adjust by TKW, not kg alone |
When Should You Increase Your Maize Seed Rate?
- Germination test result below 85% on stored or farm-saved seed
- Heavy clay or crusted soil that reduces emergence even from viable seed
- Manual sowing by hand or animal-drawn planter with less placement precision
- Late planting in a shortened season where gap-filling is not practical
- History of soil pest pressure such as wireworm or cutworm in the field
- High weed pressure where seedling competition risk is elevated
When Should You Reduce Your Maize Seed Rate?
- Precision planter with singulation accuracy above 95%
- Certified seed with labeled germination of 95% or above and purity above 98%
- Fully irrigated field with reliable water supply and high soil fertility
- Wide-row system already designed for lower target populations
- Late-maturing large-frame variety that requires individual space per plant
Maize Seed Requirement Chart by Acreage
Based on hybrid seed at 90% germination and 98% purity, targeting 27,000 plants per acre at 75 x 25 cm spacing.
| Field Area | Seed Required | 10 kg Bags |
| 0.5 acre | 4.5–5 kg | 1 bag |
| 1 acre | 9–10 kg | 1–2 bags |
| 2 acres | 18–20 kg | 2 bags |
| 5 acres | 45–50 kg | 5 bags |
| 10 acres | 90–100 kg | 9–10 bags |
| 20 acres | 180–200 kg | 18–20 bags |
| 1 hectare | 20–22 kg | 3 bags |
| 5 hectares | 100–110 kg | 11 bags |
How to Test Maize Seed Germination at Home
Run this test before planting any seed stored from the previous season or sourced from an unverified channel. It takes 7 to 10 days and requires no lab equipment.
- Moisten two paper towels until damp, not dripping.
- Place 50 to 100 seeds evenly on one towel. Fold the second towel over the top.
- Roll loosely and seal in a zip-lock bag left partially open for air circulation.
- Keep at 25 to 30 degrees Celsius for 7 to 10 days.
- Count germinated seeds, divide by seeds tested, multiply by 100.
Example: 43 germinated from 50 tested = 86% germination. Enter 86 into the formula.
The Food and Agriculture Organization (FAO) recommends germination testing on all stored seed lots before field planting to prevent costly stand failures.
How the Right Maize Seed Rate Saves Money and Improves Yield
Overplanting wastes seed and creates crowding stress. Underplanting leaves yield on the field. The difference is typically 5 to 15% of total yield.
CIMMYT data shows fields 10% below optimal plant population yield 5 to 8% less under good growing conditions. At maize grain prices of $200 per metric ton, a 5% yield gap on 10 acres costs $100 to $150 in lost revenue. To estimate the financial impact of different yield levels, try our Crop Profit Calculator. The seed calculation takes under 10 minutes.
Our Crop Yield Calculator can help you model different planting population scenarios against expected yield before you commit to a seed rate.
Common Mistakes When Calculating Maize Seed Rate
- Using a flat kg per acre figure without adjusting for germination or purity
- Assuming certified seed means 95% germination without reading the bag label
- Ignoring Thousand-Kernel Weight when switching between seed varieties
- Measuring acreage inaccurately. A 10% acreage error creates the same error in total seed requirement
- Buying exactly the calculated amount with no buffer for end rows or replanting
- Treating hybrid seed and OPV seed as interchangeable in the maize seed requirement calculator
Frequently Asked Questions
How much maize seed is required for 1 acre?
Most hybrid maize varieties require 8 to 10 kg per acre under standard conditions. Seed below 90% germination or below 97% purity may need 10 to 12 kg to reach the same plant stand.
How many maize seed bags are needed for 1 acre?
For certified hybrid seed, one 10 kg bag is usually enough for one acre. For stored or farm-saved seed, an extra bag may be required depending on germination and purity test results. Always test before buying.
What is the difference between maize seed rate and plant population?
Seed rate is how many kilograms of seed you sow per acre. Plant population is how many living plants actually establish in the field. Seed rate is an input decision; plant population is the field outcome. A 9 kg seed rate does not guarantee 27,000 plants if germination is 80%. That gap is exactly what the adjustment formula corrects for.
Can maize seed rate be calculated without germination percentage?
Yes, but the result will likely be inaccurate. Without germination data, most calculators default to 90% or 95%. If your actual seed tests lower, you will plant too little and miss your target population. For certified seed with a labeled germination figure, you can use the default. For any stored or farm-saved seed, always test germination first.
How many maize seeds are in 1 kg?
Between 2,200 and 3,500 seeds per kg depending on variety and Thousand-Kernel Weight (TKW). A TKW of 300 grams gives roughly 3,333 seeds per kg. Check the seed bag label if TKW is listed.
How many maize plants can grow on one acre?
The standard target is 27,000 to 33,000 plants per acre for hybrid maize. High-density planting targets 33,000 to 40,000. Fodder and silage maize run 100,000 or more per acre.
What is the maize seed rate per hectare?
Hybrid maize requires 20 to 25 kg per hectare under irrigated conditions and 22 to 28 kg per hectare for rainfed conditions. One hectare equals 2.47 acres.
Does germination percentage affect seed rate?
Yes. Every 5% drop in germination adds roughly 0.5 kg per acre to your requirement. Seed at 80% germination needs about 20% more quantity than seed at 95% germination to reach the same plant population.
What happens if maize is planted too densely?
Excessive plant population causes competition for light, water, and nutrients. Plants produce smaller, poorly filled cobs. Stalk diameter decreases, raising lodging risk. In rainfed fields, crowding under moisture stress can reduce yield more than underplanting would have.
What happens if maize population is too low?
Fields below optimal plant population leave yield potential unrealized. Each missing plant is a yield gap that no input increase can fill mid-season. CIMMYT research shows fields 10% below optimal population yield 5 to 8% less even under good growing conditions.
Should seed rate be increased during late planting?
Yes, in most cases. Late planting shortens the growing season, leaving less time to replant gaps. Increasing seed rate by 5 to 10% when planting late reduces the risk of stand gaps that cannot be corrected before the crop closes canopy.
Can I reduce seed rate with a precision planter?
Yes. A precision planter with singulation accuracy above 95% reduces skips and double-planting. This typically allows a 5 to 10% reduction in seed rate compared to manual sowing while still hitting the target plant population.
Does maize variety affect seed rate?
Yes. Varieties differ in TKW, plant frame size, and recommended spacing. High-density single-cross hybrids are designed for closer spacing and higher seed rates. Late-maturing large-frame varieties use lower populations and lower kg-per-acre rates. Always check the variety-specific cultivation guide before finalizing your seed rate.
- Maize Spacing Calculator — calculate row and plant spacing for any target population
- Plant Population Calculator — convert spacing to plants per acre or per hectare
- Seed Germination Calculator — test and adjust for different germination percentages
- Maize Fertilizer Calculator — estimate nitrogen, phosphorus, and potassium requirements by yield target
- Maize Yield Calculator — model yield outcomes at different plant populations and inputs
- Maize Cultivation Guide — full agronomic guide from land preparation through harvest
Reference Sources
Food and Agriculture Organization (FAO)
USDA National Institute of Food and Agriculture (NIFA)
Disclaimer: Gardening information on Agri Farming is for educational purposes only. Results vary by climate, soil, weather, and growing conditions. For region-specific advice, consult your local Cooperative Extension Service before making major gardening or soil changes.
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