Overseeding calculator
A 5,000 sq ft lawn overseeded at 3 lb per 1,000 sq ft needs 15 lb of seed. Enter your lawn area and the overseeding rate from the bag or an extension guide, and get the total pounds to buy before fall seeding. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Area
- 5,000
- Interest rate
- 3
- Seed pounds
- 15
- Unit area
- sqft
- Unit rate
- lb_per_1000_sqft
- Unit seed
- lb
This overseeding calculator estimates how many pounds of grass seed you need to thicken an existing lawn from two numbers everyone already has: the yard area in square feet and the overseeding rate printed on the bag or in extension guides as pounds per thousand square feet. Overseeding rates are intentionally lighter than new-lawn rates so you do not smother living turf while filling thin spots and improving density. The engine multiplies area by that published rate and divides by one thousand, so a five-thousand-square-foot lawn at three pounds per thousand feet needs fifteen pounds of seed with no intermediate unit conversion. Zero and negative inputs are rejected, results are fully deterministic, and nothing is stored after the response.
What overseeding seed pounds mean and how the result is defined
Overseeding seed pounds here means the total mass of grass seed implied by your measured lawn surface and a published overseeding rate expressed per one thousand square feet. Seed bags, university extension sheets, and contractor plant schedules almost always quote overseed rates that way—commonly two to five pounds per thousand square feet for cool-season blends—rather than as pounds per single square foot.
A twelve-thousand-square-foot yard at two and a half pounds per thousand feet yields thirty pounds; a small two-thousand-square-foot front strip at four pounds per thousand feet yields eight pounds. Treat the figure as a planning estimate and round slightly upward for edges, bare patches, and the extra seed many labels recommend when soil contact is imperfect.
Where overseeding estimates fit for DIY, quotes, and software
DIY gardeners meet this problem every cool-season fall when a thinning lawn needs a lighter overseed rate than a bare-soil new installation, when the bag aisle quotes pounds per thousand feet while the tape measure gives total square feet, or when a patch repair must not open a commercial bag without knowing the true need.
Trade estimators use the same identity across dozens of lots: measure plan area in square feet, pick the overseed rate from the seed label or the job specification, and multiply-and-divide for total pounds before ordering bags or pallets. Teachers and vocational trainers can pre-generate answer keys for modest lawn sizes without trusting opaque mobile apps that switch units mid-form or forget that a thousand-square-foot rate must be scaled to the whole yard.
Developers call the same contract from scripts to seed deterministic test vectors for landscape calculators, to normalise user-entered lawn sizes before a cart suggests bag counts, or to satisfy programming-challenge statements that demand seed mass rather than a hand-waved about-two-bags guess. Product tools use the multiply-and-divide when a homeowner types five thousand square feet and a three-pound-per-thousand rate and the UI must show total seed before checkout.
What you can do with it
Contractor multi-lot renovation quotes
Feed measured lot areas and specified overseed rates from the plant schedule to produce reproducible seed totals for bids.
FAQ
What does the overseeding calculator cost?
It is free in your browser on this page.
How are seed pounds calculated?
Area is square feet; rate is pounds of seed per 1,000 square feet.
What if I enter zero or negative area or rate?
Both area and rate must be strictly positive numbers greater than zero.
How is this different from a general grass seed calculator?
This tool expects the industry overseeding rate in pounds per thousand square feet and divides by 1,000 for you. General tools often expect seed per single square foot of area.
What overseeding rate should I use?
Use the overseeding rate printed on the seed bag or in an extension guide, in pounds per 1,000 square feet. Cool-season blends are commonly 2 to 5 pounds. Overseeding rates are lighter than new-lawn rates so the new seed does not smother the living grass.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/home/overseeding \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"area":5000,"rate":3}'const res = await fetch("https://api.kit.forhosting.com/home/overseeding", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"area": 5000,
"rate": 3
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/home/overseeding",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"area": 5000,
"rate": 3
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/home/overseeding", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"area":5000,"rate":3}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"area":5000,"rate":3}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/home/overseeding", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"area": 5000,
"rate": 3
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "home.overseeding",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_abs | 1000000000 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Use it free in the browser before a fall overseed run, or call the API at $0.002 per successful request when quoting renovation jobs in landscape software.
What overseeding seed pounds mean and how the result is defined
The calculator therefore keeps the industry form of the rate: seed_pounds equals area in square feet times rate in pounds per thousand feet, divided by one thousand. The JSON response echoes the rounded area and rate, the seed_pounds total, unit tags for square feet, pounds per thousand square feet, and pounds, a method tag area_times_rate_per_thousand, and a short formula string for worksheets and goldens. There is no species picker, climate map, or germination-percentage correction: the page answers only the pounds of seed the area-and-rate identity produces, with stable numbers suitable for shopping lists, contractor quotes, and API consumers that must match examples run after run.
How inputs are read, validated, and kept reproducible
Preferred fields are area for lawn surface in square feet and rate for overseeding pounds per one thousand square feet, plus optional precision for display rounding. Aliases such as area_sqft, lawn_area, sqft, and square_feet for area, and rate_per_1000, lb_per_1000, pounds_per_1000, and overseed_rate for rate are accepted so spreadsheets, query strings, and typed forms can reuse the same contract without renaming columns. Every numeric field must be finite; non-positive area or rate is rejected with invalid_input so a zero-area form field cannot silently claim free seed and a negative rate cannot invert the physics of planting. An optional precision field, with aliases decimals and dp, chooses how many decimal places to expose for area, rate, and seed_pounds, defaulting to four and capped at fifteen so JSON goldens stay stable across engines. Pair the free browser run on this page with the priced API when you need the identical mathematical result inside an automated pipeline without re-implementing the overseeding formula yourself.
Where overseeding estimates fit for DIY, quotes, and software
On this page the work runs entirely in your browser; through the API each successful lookup costs $0.002, failed validation is not charged, and nothing is stored after the response returns. That split—free interactive exploration and a priced, identical API—matches the rest of the KIT tier-A catalog and lets you move from a backyard demo to an automated quoting pipeline without changing the mathematical result. Pair it with unit converters when your tape measure and bag label disagree on systems of units, and with other home or geometry endpoints when you are building a small lab of free, deterministic planning helpers for outdoor renovation projects.
Integration use cases
Fall overseed shopping list
Enter total lawn square footage and the bag’s lb-per-1000-ft² overseed rate, then buy the exact seed_pounds you need.
Deterministic fixtures for landscape apps
Generate stable seed_pounds values for unit tests in renovation planners, e-commerce bag suggesters, and CI checks.
Technical questions
My bag says 3 lb per 1,000 sq ft — what do I enter?
Pass rate=3 with area in square feet. For area=5000 the calculator returns seed_pounds=15.