Free lawn & garden calculators — no app, no login

Enter your yard once.
Every tool knows it.

Grass type, square footage, zone — set them here and every calculator on the site is already sized to your lawn: pounds of seed, pounds of fertilizer, minutes on the sprinkler. Then the planner lays it out across the year.

See the lawn planner Browse all calculators

Extension-sourced rates, cited
Remembers your yard
Shows the math

1

Set up your yard

Area, grass type and zone — a rough guess is fine to start. Saved in your browser only.
2

Run any tool

Fertilizer, seed, mulch, watering — each one opens already sized to your lawn.
3

Get the dated plan

The planner turns it into a year: what, how much, and when — printable, with calendar reminders.

The centerpiece

A dated plan for your lawn, not a generic calendar

Tell the planner your grass type, square footage and zone. It returns a month-by-month schedule with the quantities already worked out — pounds of seed, pounds of your fertilizer, minutes of watering — using the same calculators you'll find below.

Print it. One page for the garage wall — no email, no signup.
Add it to your calendar. Download the dates as an .ics file; get your own September reminder.
Share the link. Every input lives in the URL, so the plan rebuilds anywhere.

Open the planner

Sample plan

Tall fescue · 5,000 sq ft · zone 6b · first frost ≈ Oct 20

Cool-season

Sep 1–15 Core aerate and overseed 17.5 lb of tall fescue seed 3.5 lb per 1,000 sq ft × 5,000 sq ft
Sep 1–15 Fertilize, 1 lb N per 1,000 sq ft 20.8 lb of 24-0-6 2 × 15 lb bags, 9.2 lb left over
Oct 15–31 Second fall feeding, 1 lb N 20.8 lb of 24-0-6 Second fall feeding — the one that builds the spring lawn
Late Oct–Nov Final mow a notch lower 2½ in After first frost (≈ Oct 20); then blow out the irrigation

J F M A M J J A S O N D

fertilize seed water focus

The lawn calendar

What to do in October

The right job depends on whether your grass grows in cool weather or warm — pick yours. The planner shifts these dates to your zone.

Cool-season Feed and fight weeds

Priority Second fall feeding, 1 lb N — this is where the thick spring lawn comes from. Lawn Fertilizer calculator →
Best month for broadleaf weed control — dandelions and clover are pulling reserves to the roots.
Keep mowing; mulch leaves into the turf instead of raking.

Template adapted from university extension lawn calendars (Penn State, Maryland, Purdue; Clemson, UGA, Texas A&M). Your zone moves these dates by weeks — that's what the planner is for.

The toolbox

30 calculators, grouped the way you use them

Lawn and cost tools read your yard profile; indoor tools read a separate grow-space profile; bulk-material tools need neither.

Lawn

Seed, feed, lime and sod — sized to your square footage.

Lawn Area Add up rectangles, circles and odd corners; subtract the house and drive. Feeds every other tool. Lawn Fertilizer Bag NPK + your target pounds of N → pounds of product, bags and spreader coverage. Grass Seed Pounds of seed by species for a new lawn or an overseed — and how many bags. Sod Rolls, pallets and waste allowance for your area. Lime Application Soil pH and texture → pounds of lime per 1,000 sq ft, split into safe applications. Topdressing Sand Leveling sand or compost at ¼–½ in: cubic yards, bags and weight. Sprayer & Tank Mix Calibrate your sprayer, then turn the rate on your label into what goes in this tank — including the last, part-full one. Spreader Calibration Weigh what your spreader puts down on a measured strip → the setting that hits your label rate, and how far apart to walk your passes. Pre-Emergent Timing When soil hits 55 °F in your zone, whether you've missed it, when the second application goes down — and whether it blocks your fall overseed.

Garden & Beds

Bulk materials and planting math — the spring supply run.

Mulch Area and depth → cubic yards or bags, plus the bulk-vs-bag price crossover. Topsoil Cubic yards and tons to fill, grade or top up — with the density that matches your soil. Raised Bed Soil Bed dimensions → fill volume → bags of each component in the classic mixes. Soil Blend Compost / topsoil / aeration percentages → how much of each to buy. Plant Spacing Rows or square-foot method: how many plants fit a bed. Seed Starting Dates Your last frost date → sow-indoors, transplant and direct-sow dates for each crop. Gravel & Paver Base Cubic yards and tons of gravel, sand or base by depth — with compaction.

Irrigation

Measure what your sprinklers actually put down, then set the timer.

Sprinkler Precipitation Rate The catch-cup test, formalized: inches per hour and how even your coverage is. Watering Run Time Target inches per week → minutes per zone, days per week, cycle-and-soak. Drip Irrigation Emitter count and GPH → zone flow, run time and max emitters per line. Zone GPM & Pipe Sizing Heads per zone against your supply, and the pipe size that keeps pressure. Rainwater Harvesting Roof area × rainfall → gallons you could catch, and the barrel or tank to hold it. Irrigation Water Cost Inches applied → gallons → dollars per month, and what a smarter schedule saves.

Indoor Growing

Hydroponics and grow tents — the numbers growers check daily. Set up your grow space →

VPD Temperature and humidity → vapor pressure deficit, with stage targets and a printable chart. DLI PPFD × photoperiod → daily light integral, against crop targets. Grow Light Coverage Space and target PPFD → the light output and wattage you actually need. EC ↔ PPM The 500 vs 700 scale, explained and converted. Nutrient Dosing Target EC and reservoir size → milliliters of each part. Reservoir Top-Off Current EC and volume → how much water or nutrient brings it back on target.

Costs

Is it worth it? Payback math before you buy.

Robot Mower Savings Mowing service vs robot: price, power, blades → payback in seasons. Lawn Care Annual Cost DIY vs service for your square footage: fertilizer, seed, water, fuel and time.

Guides

The why behind the numbers

Short, honest guides that pair with the calculators — what the fertilizer numbers mean, how to measure your sprinklers, when each job belongs on the calendar.

Understanding NPK: what the fertilizer numbers mean The three numbers, pounds of actual nitrogen, and why "covers 5,000 sq ft" is a marketing rate. When to fertilize: cool- vs warm-season schedules Fall-heavy for bluegrass and fescue, summer-heavy for bermuda — and why spring is the month to go easy. How much to water a lawn — and how to measure it "One inch a week" is a placeholder. The tuna-can test is the real number.

All guides →

Math you can check

Rates come from university extension publications and are cited on each page, with a “show the math” breakdown on every result. Where the label disagrees, the label wins — we say so.

Private by design

No accounts, no email gate on the printables. Your yard and grow-space profiles live in your browser and nowhere else.

Honest recommendations

When a result points at a product, it's the one the numbers justify — and we say so when the cheap option wins. Some links earn us a commission; that never changes the numbers.

Enter your yard once.Every tool knows it.

Set up your yard

Run any tool

Get the dated plan