Garden & Outdoors calculators

A focused hub of formula-based tools in the garden & outdoors category. Each page includes the calculator, formula, assumptions, and related tools.

Updated 14 Aug 2026

Compost C:N Ratio Blender Calculator

Calculate compost C:N ratio, moisture, green/brown balance, and correction amounts from common compost materials like leaves, grass, food scraps, cardboard, straw, and manure.

Updated 14 Aug 2026

Rainwater Harvesting Tank Size Calculator

Calculate annual rainwater harvest, dry-spell storage need, storm capture, overflow, and recommended tank size from roof area, rainfall, efficiency, and demand.