13 live calculators, more on the way

Garden math, done for you.

Free, fast, mobile-friendly calculators for mulch, soil, fertilizer, watering, plant spacing, lawns, and more. No sign-up, no fluff — just the numbers you need to buy the right amount and grow more.

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Pick a cluster

Eight clusters of calculators covering everything from soil and amendments to trees, shrubs, and hydroponics.

5 live

Soil & Amendments

Build healthy ground from the bottom up. Calculate exact volumes for raised beds, garden plots, and topdressing without overbuying.

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1 live

Fertilizer & Nutrients

Match the right fertilizer to the right plant at the right dose. NPK math, feeding rates, and nutrient budgets made simple.

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1 live

Watering & Irrigation

Water smarter, not more. Drip emitter counts, run times, and weekly water budgets tuned to your plants and climate.

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3 live

Spacing & Planting

Plan beds that fit. Spacing, row layout, and plant count math for raised beds, square-foot gardens, and traditional rows.

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1 live

Lawn & Landscaping

Get the right amount the first time. Grass seed, sod, mulch, and landscape material math for lawns and paths of any shape.

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1 live

Indoor Plants

Keep houseplants thriving. Pot size, watering frequency, and light calculators tuned to container-grown indoor plants.

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Hydroponics & Greenhouse

Grow more in controlled environments. Nutrient solutions, EC targets, and greenhouse heating math for soil-free growing.

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1 live

Trees & Shrubs

Understand your trees and shrubs without cutting them down. Estimate age, growth, and value from a simple trunk measurement.

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Live now

Start with a working calculator. More are landing every week.

Live

Mulch Calculator

Calculate how much mulch you need in cubic feet, cubic yards, and 2-cubic-foot bags for any garden bed or landscape area.

Live

Topsoil Calculator

Calculate how much topsoil you need in cubic yards, cubic feet, and estimated tons for raised beds, garden filling, and lawn leveling.

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Raised Bed Soil Calculator

Calculate exactly how much soil you need for a raised bed in cubic feet, cubic yards, and bags. Includes presets for common bed sizes.

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Soil Volume Calculator

Calculate how much soil you need to fill a pot, container, raised bed, or any rectangular or cylindrical space — in cubic feet, cubic yards, and liters.

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Plant Spacing Calculator

Calculate how many plants fit in any bed using proper in-row and between-row spacing. Supports row garden and square foot gardening modes with crop presets for 20+ vegetables, herbs, and flowers.

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Grass Seed Calculator

Calculate how many pounds and 50 lb bags of grass seed you need by grass type, for a new lawn or for overseeding an existing one.

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Frost Date Calculator

Estimate your last spring frost and first fall frost date range by ZIP code or hardiness zone, then get a full planting timeline built around it.

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Tree Age Calculator

Estimate how old a tree is from its trunk circumference and species — no cutting or coring required.

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NPK Calculator

Calculate fertilizer application rates, mix a liquid feed solution, or blend multiple fertilizers to approximate a target N-P-K ratio.

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Pot Size Calculator

Convert pot sizes between inches, gallons, and liters, find the recommended next size up when repotting, or look up the minimum container size for a plant or vegetable.

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Compost Calculator

Calculate how much compost you need in cubic feet, cubic yards, bags, and estimated weight — for top-dressing beds, containers, or mixing into new soil.

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Seed Starting Calendar

Get a personalized seed starting calendar based on your frost date — when to start seeds indoors, when to transplant, and when to direct sow, by crop.

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Drip Irrigation Calculator

Calculate drip irrigation run time and total water delivered based on your emitter count, flow rate, and target water amount per plant or over an area.

Built for the way you actually garden

Most gardening sites bury the calculator under ads and life-story prose. We put the tool first, the explanation second, and nothing else in the way. Every calculator updates live as you type, works offline on your phone, and gives you the answer in the units you actually buy in — bags, cubic feet, pounds.

Live results. No submit button. Type your numbers, get your answer.
Buyable units. Cubic feet, cubic yards, 2-cu-ft bags, pounds — what the store actually sells.
Mobile-first. Big tap targets, no zooming, no popups. Pinterest-friendly.
No sign-up. No account, no email wall, no upsell. Just the math.

Example output

Mulch for a 4'x8' bed at 3" deep

Cubic feet: 8.0
Cubic yards: 0.30
2-cu-ft bags: 4

Open the Mulch Calculator