Convert grass seed, fertilizer, lime, compost, topsoil, sand, mulch and other lawn care product weights between pounds, kilograms, ounces, grams, short tons and metric tonnes. Includes corrected application-rate conversions for US and metric lawn labels.
The US lawn care market sells most granular products by weight in pounds: 5 lb and 10 lb grass seed bags, 25 lb specialty seed bags, 40 lb lime bags, 50 lb fertilizer bags, and bulk material deliveries in short tons. Metric labels, international seed blends, European fertilizer guides, and many scientific lawn-care references use kilograms, grams per square meter, kilograms per 100 square meters, or kilograms per hectare. This calculator bridges those systems with exact unit factors, so a homeowner can compare products without guessing.
The core conversion is simple: 1 pound = 0.45359237 kilograms. That means a 50 lb fertilizer bag weighs 22.68 kg, a 25 lb seed bag weighs 11.34 kg, and a 10 kg grass seed bag weighs 22.05 lb. The same precision matters for smaller products. A 4 oz packet of microclover seed is 113.4 grams, while a 16 oz bottle or pouch is exactly 1 lb, or 453.6 grams.
Application rates require both a weight conversion and an area conversion. The most common US lawn rate is pounds per 1,000 square feet. The closest metric lawn-care rate is kilograms per 100 square meters or grams per square meter. The correct conversion is: 1 lb per 1,000 sq ft = 0.488 kg per 100 sq m = 4.882 g per sq m = 48.824 kg per hectare. This is why a 4 lb per 1,000 sq ft seed rate equals about 19.5 g/sq m, while a 35 g/sq m metric seed label equals about 7.17 lb per 1,000 sq ft.
Bulk lawn materials add one more possible confusion: a US short ton is 2,000 lb, while a metric ton, often called a tonne, is 1,000 kg or 2,204.6 lb. A metric ton is roughly 10.2% heavier than a short ton. For a small fertilizer bag, that difference may not matter. For five tons of compost, topdressing sand, or screened loam, it can change the delivered quantity by hundreds of pounds.
For everyday shopping, divide pounds by 2.2 to estimate kilograms and multiply kilograms by 2.2 to estimate pounds. This is close enough for comparing bag sizes. For spreader calibration, fertilizer nitrogen, seed-rate labels, or bulk orders, use the exact calculator because small rounding errors become large when multiplied across thousands of square feet.
A 50 lb fertilizer bag does not automatically cover the same area as another 50 lb fertilizer bag. Coverage depends on the nutrient analysis and label rate. A 32-0-10 fertilizer applied at 1 lb nitrogen per 1,000 sq ft uses far less product than a 10-10-10 fertilizer applied at the same nitrogen target. Use weight conversion for units, then use label rates or a fertilizer calculator for coverage.
| Pounds (lbs) | Kilograms (kg) | Ounces (oz) |
|---|---|---|
| 1 lb | 0.454 kg | 16 oz |
| 3 lbs | 1.361 kg | 48 oz |
| 5 lbs | 2.268 kg | 80 oz |
| 10 lbs | 4.536 kg | 160 oz |
| 15 lbs | 6.804 kg | 240 oz |
| 25 lbs | 11.34 kg | 400 oz |
| 40 lbs | 18.14 kg | 640 oz |
| 50 lbs | 22.68 kg | 800 oz |
| Kilograms (kg) | Pounds (lbs) | Grams (g) |
|---|---|---|
| 0.5 kg | 1.102 lbs | 500 g |
| 1 kg | 2.205 lbs | 1,000 g |
| 5 kg | 11.02 lbs | 5,000 g |
| 10 kg | 22.05 lbs | 10,000 g |
| 20 kg | 44.09 lbs | 20,000 g |
| 25 kg | 55.12 lbs | 25,000 g |
| 1 tonne | 2,204.6 lbs | 1,000,000 g |
| lbs/1K sq ft | kg/100 sq m | kg/ha |
|---|---|---|
| 1 lb | 0.488 kg | 48.82 kg |
| 2 lbs | 0.976 kg | 97.65 kg |
| 3 lbs | 1.465 kg | 146.47 kg |
| 4 lbs | 1.953 kg | 195.30 kg |
| 5 lbs | 2.441 kg | 244.12 kg |
| 10 lbs | 4.882 kg | 488.24 kg |
1 lb/1,000 sq ft = 48.824 kg/ha = 0.4882 kg/100 sq m = 4.882 g/sq m
Weight conversion is universal, but the way you use the converted number depends on whether you are spreading seed, applying fertilizer, correcting soil pH, or ordering bulk material.
Grass seed is usually purchased by bag weight but applied by rate. A 10 kg bag may look smaller than a 25 lb bag, but it is only about 2.95 lb lighter. The more important question is how many square feet or square meters the bag covers at your chosen seeding rate. For example, if a tall fescue blend is applied at 8 lb per 1,000 sq ft, a 25 lb bag covers about 3,125 sq ft. If the same blend is sold as an 11.34 kg bag, it is effectively the same 25 lb bag in metric form.
For overseeding, seed rates are lower. A lawn that needs 4 lb per 1,000 sq ft uses 19.5 g/sq m. A new lawn that needs 8 lb per 1,000 sq ft uses 39.1 g/sq m. This helps compare US labels with metric labels that may recommend 25–50 g/sq m depending on species, germination target, and whether the area is bare soil or an existing thin lawn.
Fertilizer conversion has two layers. First, convert the product weight. A 50 lb bag equals 22.68 kg. Second, calculate nutrient content using the N-P-K analysis. A 50 lb bag of 24-0-12 contains 12 lb of nitrogen, 0 lb phosphate, and 6 lb potash. In metric terms, that same bag contains 5.44 kg nitrogen and 2.72 kg potash. This distinction prevents a common mistake: applying a fertilizer by bag weight without checking the nutrient strength.
When you convert a fertilizer application rate, keep the nutrient target in mind. A common lawn target is 1 lb actual nitrogen per 1,000 sq ft. With 20% nitrogen fertilizer, you need 5 lb product per 1,000 sq ft. With 32% nitrogen fertilizer, you need only 3.13 lb product per 1,000 sq ft. Both can be converted to kg/100 sq m, but the product amount will be different because the analysis is different.
Lime, gypsum, sulfur and other soil amendments should be applied according to a soil test or label guidance, not by guesswork. A recommendation of 50 lb lime per 1,000 sq ft converts to 24.41 kg per 100 sq m. If your lawn is 8,000 sq ft, that recommendation means 400 lb total, or 181.44 kg total. If the store sells lime in 25 kg bags, you would need eight bags for the full rate, with a little product left over.
For topdressing, soil repair and mulch, volume often matters more than weight. A lawn topdressing project is normally calculated by area and depth: square footage multiplied by target depth equals cubic feet or cubic yards. Weight still matters for delivery limits, lifting, storage and price comparison, but two cubic yards of compost can have different weights depending on moisture and material blend. Use this converter for weight comparisons and use a volume calculator when depth is the primary requirement.
| Product | US Bag | Metric Equivalent |
|---|---|---|
| Small seed bag | 5 lb | 2.27 kg |
| Mid seed bag | 10 lb | 4.54 kg |
| Pro seed bag | 25 lb | 11.34 kg |
| Large fertilizer | 50 lb | 22.68 kg |
| Lime bag | 40 lb | 18.14 kg |
| Metric pro bag | 25 kg | 55.12 lb |
| 1,000 sq ft | 92.903 sq m |
| 100 sq m | 1,076.39 sq ft |
| 1 acre | 43,560 sq ft |
| 1 hectare | 10,000 sq m |
| 1 hectare | 2.471 acres |
Dry ounces measure weight, while fluid ounces measure volume. A dry 8 oz bag of soluble powder weighs 226.8 grams. An 8 fl oz liquid bottle is not automatically 226.8 grams because liquid density varies by product.
For most lawn projects, the right amount of precision depends on the product risk. Seed and compost tolerate practical rounding; fertilizer, herbicide, lime and soluble powders deserve tighter measurement.
Rounding a 50 lb fertilizer bag to 22.7 kg or a 25 kg bag to 55.1 lb is accurate enough for shopping, storage, delivery comparisons and bag-count planning. Grass seed also tolerates modest rounding because seed distribution is never perfectly uniform across an entire lawn. If the calculator says you need 18.6 lb of seed, buying a 20 lb total supply is normally sensible.
Use exact conversion factors when calibrating a spreader, converting a pesticide label, measuring soluble fertilizer, or applying lime based on a soil test. These products can harm grass, stain surfaces, or violate label directions if applied too heavily. A digital kitchen scale or postal scale is very useful for small quantities under one pound, especially when converting ounces to grams.
Do not round once from pounds to kilograms and then round again when converting the rate. Convert from the original value directly to the target unit. For example, convert 3.75 lb/1,000 sq ft straight to 18.31 g/sq m rather than rounding 3.75 lb to 1.7 kg and then converting again. The calculator does this automatically by using a base unit internally.
For fertilizer and amendments, measure within about 5% of the target rate. For seed, stay close but prioritize even coverage. For herbicides and pesticides, always follow the product label exactly and use a calibrated sprayer or spreader.
| Shopping comparison | 1 decimal place is enough |
| Seed spreading | Nearest 0.1 lb or 50 g |
| Fertilizer spreading | Nearest 0.1 lb or 25 g |
| Soluble powders | Use gram-level scale |
| Bulk deliveries | Confirm ton type first |
Real-world lbs to kg conversions for common lawn care product scenarios.
Use the converter as the first step whenever your lawn area, product label, soil-test report, or spreader chart uses a different measurement system.
A US grass seed guide may recommend 6 lb per 1,000 sq ft for a new tall fescue lawn. A metric seed bag may recommend 30 g/sq m. These are nearly the same rate: 6 lb/1,000 sq ft converts to 29.3 g/sq m. This is useful when a seed blend is sold in kilograms but the lawn area is measured in square feet.
Fertilizer labels list both bag weight and nutrient analysis. A 50 lb 24-0-12 bag weighs 22.68 kg, but it contains 12 lb of actual nitrogen because 24% of the bag is nitrogen. In metric terms, that is 5.44 kg of nitrogen. Weight conversion tells you the bag mass; nutrient math tells you how much active nutrient you are applying.
Soil tests may recommend lime in pounds per 1,000 sq ft, while imported lime products may be labeled in kilograms. A 40 lb/1,000 sq ft recommendation converts to 19.53 kg/100 sq m. For a 5,000 sq ft lawn, that is 200 lb total or 90.72 kg total. The bag calculator makes it easy to decide whether two 50 lb bags, five 20 kg bags, or a bulk delivery is the better purchase.
Bulk topsoil, compost, sand and gravel are often sold by the cubic yard, but suppliers sometimes provide approximate weight. Moisture changes weight dramatically, so a cubic yard of damp compost may weigh much more than a dry cubic yard. Use pounds-to-kilograms conversion only when the supplier gives a measured weight, and use a volume calculator for depth-based topdressing or soil projects.
| lbs to kg | lbs × 0.45359237 |
| kg to lbs | kg × 2.20462262 |
| oz to g | oz × 28.349523125 |
| g to oz | g × 0.03527396 |
| lb/1K sq ft to g/sq m | rate × 4.88243 |
| g/sq m to lb/1K sq ft | rate × 0.204816 |
| lb/1K sq ft to kg/ha | rate × 48.8243 |
After converting the rate, always calibrate your spreader on a measured test area. Two products with the same weight can flow very differently because granule size, dust level and coating affect spreader output.
Common questions about converting lawn product weights and application rates between US and metric units.
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