Extension fertilizer rates often come in pounds per acre or per 1000 square feet, while a home bed is measured in 100 square feet or square meters. This converter translates garden units for fertilizer rate, area, and length so you can size a recommendation to your bed.
Try a preset:
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What Your Result Means: the result is your value expressed in the target unit, using exact conversion factors. Use it to scale an extension rate down to your bed, or to switch between imperial and metric garden units.
How Do You Convert Garden Units?
Choose what to convert, enter a value, and pick the units to convert from and to. The tool handles fertilizer application rates, area, and length, the units that come up when sizing a fertilizer or a bed.
- Choose a Category, fertilizer rate, area, or length.
- Enter a Value and the unit it is in.
- Pick the Target Unit, then convert to see the result and the per-unit factor.
What Each Result Means
| Output | What It Tells You |
|---|---|
| Result | Your value in the target unit |
| Input | The value and unit you entered |
| Per-unit factor | One from-unit expressed in the target |
Handy Garden Conversions
Common conversions this tool handles, worth keeping in mind.
| From | Equals |
|---|---|
| 1 lb per 100 sq ft | 435.6 lb per acre |
| 1 lb per 100 sq ft | 48.8 g per sq m |
| 1 lb per 1000 sq ft | 43.6 lb per acre |
| 1 acre | 43,560 sq ft |
| 1 sq foot | 0.0929 sq meters |
| 1 foot | 0.305 meters |
How Does the Conversion Work?
Each unit has an exact factor to a base unit: grams per square meter for fertilizer rate, square meters for area, and meters for length. The tool converts your value to the base, then into the target unit.
Fertilizer base: grams per square meter
Area base: square meters
Length base: meters
Because the factors are exact, the only rounding is in how the result is displayed. Fertilizer rate uses weight per area, so both the weight and the area unit are built into each factor.
Worked Example
Say an extension guide recommends 1.5 pounds of fertilizer per 100 square feet, and you want it per acre to compare with a bag label. One pound per 100 square feet is 435.6 pounds per acre, so 1.5 becomes about 653 pounds per acre. The same 1.5 pounds per 100 square feet is also about 73 grams per square meter.
Factors That Change Your Conversion
- Rate versus amount: a fertilizer rate is weight per area; do not confuse it with a plain weight.
- Area basis: per 100 sq ft, per 1000 sq ft, and per acre differ by large multiples, so check which the label uses.
- Imperial versus metric: the tool switches between the two, which is handy for international products.
- Nutrient versus product: this converts the product rate, not the actual nutrient; use the fertilizer calculator for nitrogen.
- Rounding: results are rounded for display, so very small values keep more decimals.
Understanding Your Outputs
| Output | Meaning | Best Used For |
|---|---|---|
| Result | Converted value | Sizing to your bed |
| Input | What you entered | Checking the setup |
| Per-unit factor | One unit converted | Quick mental math |
When to Use It
Use it when an extension rate is in per-acre or metric units and your bed is in square feet, when comparing product labels, or when following an international guide. It pairs with the fertilizer calculator, which turns a rate into an amount for your bed.
Common Mistakes to Avoid
- Mixing rate and weight: a rate always includes an area, unlike a plain weight in pounds.
- Wrong area basis: per 100 and per 1000 square feet differ tenfold; read the label carefully.
- Using it for cooking: for cups, cans, and food weights, use the measurement converter instead.
- Forgetting nutrient percent: converting the product rate does not account for the N-P-K strength.
- Over-precision: garden application does not need many decimals; round to something practical.
Accuracy and Limitations
The conversions use exact factors and are accurate.
What It Does Well: converts fertilizer rate, area, and length between imperial and metric garden units.
What It Does Not Do: convert cooking measures, account for fertilizer nutrient percent, or replace a soil test. Use the measurement and fertilizer tools for those.
Methodology
Method: factor-based conversion through a base unit per category. Inputs Used: category, value, from-unit, to-unit. Bases: fertilizer rate in grams per square meter, area in square meters, length in meters. Key factors: 1 lb per 100 sq ft = 48.82 g per sq m = 435.6 lb per acre; 1 sq ft = 0.092903 sq m; 1 acre = 4046.86 sq m; 1 ft = 0.3048 m; 1 in = 2.54 cm. Formula: result = value x factor(from) divided by factor(to). Rounding: display only, with more decimals for small values. Edge cases: a missing or negative value prompts for a number; identical units return the input.
Sources: NIST Guide to the SI, Appendix B.8 – Conversion Factors, Iowa State University Extension – Growing Tomatoes, Royal Horticultural Society – Tomatoes, The Old Farmer’s Almanac – Tomatoes. Last reviewed: September 24, 2026 · Reviewed by Aiza Anwar.
Frequently Asked Questions
How do I convert pounds per 100 square feet to pounds per acre?
Multiply by 435.6, since an acre is 43,560 square feet, or 435.6 units of 100 square feet. So 1.5 lb per 100 sq ft is about 653 lb per acre.
What is pounds per 1000 square feet?
A common lawn and garden rate. One pound per 1000 square feet equals about 43.6 pounds per acre, or 4.9 grams per square meter.
How many square feet are in an acre?
An acre is 43,560 square feet, or about 4,047 square meters. A typical home bed is a tiny fraction of that.
How do I convert a fertilizer rate to grams per square meter?
Pick the fertilizer rate category, enter the imperial rate, and convert to grams per square meter. One pound per 100 square feet is about 48.8 grams per square meter.
How do I convert square feet to square meters?
Multiply square feet by 0.0929. So a 32 square foot bed is about 3 square meters. The tool does it for any value.
How big is a hectare?
A hectare is 10,000 square meters, about 2.47 acres or 107,639 square feet. It is a metric unit used in larger-scale growing.
How do I convert feet to meters?
Multiply feet by 0.3048. So an 8 foot bed is about 2.44 meters. One inch is 2.54 centimeters.
Why do extension guides use per-acre rates?
They serve farms and large plots. For a home bed, convert the rate down to per 100 square feet or per square meter to apply the right amount.
Does this convert cooking measurements?
No. For tomato weights, cups, and can sizes, use the Measurement Converter. This tool handles growing units only.
Related Tomato Tools
Turn It into an Amount with the Fertilizer Calculator
This converter uses exact factors for garden units. It does not convert cooking measures or account for fertilizer nutrient percent. Spotted an error? Tell us here.