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The Gardening Calculator You Actually Need

Skip the guesswork. Get exact plant counts, soil volumes, frost dates, and planting schedules — calculated instantly for your garden.

Browse All 30 Tools → Try Plant Spacing Free

✓ NOAA Verified Data  ·  ✓ Zero Tracking Cookies  ·  ✓ Works on Any Device

NOAA & USDA Data Instant Results Mobile Friendly Always Free

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Start With These Calculators

The tools home gardeners reach for most — pick what you need right now.

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Three Steps to a Better Garden

No complicated setup. No learning curve. Just answers.

01

Choose Your Tool

Browse 30 free calculators organized by category. Spacing, soil, timing, fertilizer, irrigation, planning.

02

Enter Your Details

Simple inputs — bed size, ZIP code, or plant type. No gardening degree required, no account needed.

03

Get Your Answer

Results calculate instantly using NOAA climate data and university extension service guidelines.

30

Free Tools

200+

Plants

NOAA

Climate Data

26

USDA Zones

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Every Calculator You Need

Browse the complete collection by category — all free, mobile-friendly, and live now.

📐 Spacing Tools

🪣 Soil & Timing

📅 Planting & Harvest

🌿 Water & Planning

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Built on Real Data, Not Guesses

Accurate Formulas

Every formula follows guidelines from Cornell, Purdue, and UC Davis Cooperative Extension services — not rough estimates.

Real Climate Data

Frost dates and planting windows come from NOAA's 30-year climate normals — the same data professional growers rely on.

Zero Friction

No accounts. No emails. No paywalls. Open the tool, enter your numbers, get your answer. Takes under 30 seconds.

Works Everywhere

Every calculator is fully mobile-optimized. Use it in the garden with your phone in hand — even on slow connections.

GardenCalc By the Numbers

Free Calculators
30
Plants in Database
200+
USDA Hardiness Zones
26
NOAA Climate Data
30yr

Common Questions

Yes — every one of GardenCalc's 30 tools is completely free, with no account required and no usage limits. We believe basic gardening math should never sit behind a paywall.
Our formulas follow standard horticultural guidelines from university extension services. Plant spacing uses the same triangular and grid pattern formulas taught in permaculture courses. Soil volume includes a 10% compaction buffer.
Frost dates use NOAA's 30-year climate normals — the same dataset used by professional growers and seed companies. Dates are averages; actual timing can vary 1–2 weeks based on your local microclimate and year-to-year weather.
Every calculator is fully mobile-optimized. The inputs work with phone keyboards, results are readable in sunlight, and most tools work offline once the page has loaded.
Developed by Mel Bartholomew, square foot gardening divides a raised bed into 1-square-foot sections, each holding a specific plant count based on mature size. Tomatoes get 1 per square foot; radishes fit 16. Our planner automates the math.
Use our USDA Zone Lookup tool — enter your ZIP code for your zone, temperature range, frost-free days, and a list of plants that thrive in your area. Based on the 2023 USDA zone map.

Ready to Plan Your Best Garden Yet?

30 free tools. Zero signup. Instant answers.

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