GDU Calculator is the field-ready Growing Degree Unit tracker and calculator built for farmers and agronomists. Set up your fields, enter a planting date, and the app automatically pulls historical and forecast weather to calculate accumulated GDUs and show you exactly where your crop stands in its growth cycle.

A new added option allows you to track plant growth by base growing days. Every day where the temperature is above the base growing temperature of the crop is counted. When crop stages are based on days since planting, instead of Growing Degree Days.

🌱 SUPPORTED CROPS
Corn, Soybean, Wheat, Barley, Oats, Canola, Flax, Sunflower, Field Peas, Dry
Beans, Sugar Beet, Potato, Alfalfa, Cool-Season Grass — and fully customizable crops with your own base temperature and growth stages.

📊 WHAT IT DOES
• Accumulates GDUs from planting date using historical weather data
• Projects forward with a 7-day forecast so you can plan ahead
• Shows key growth stages (emergence, silking, maturity, etc.) on a live chart
• Supports multiple GDU calculation methods: Simple, Modified (corn), and Capped
• Tracks field operations — planting, herbicide, fungicide, fertilizer,
irrigation, scouting, harvest, and more — plotted right on your GDU chart
• Manages multiple fields, each with its own crop, planting date, and location

🗺️ LOCATION & WEATHER
Set a field location by searching a place name or tapping "Use My Location" for GPS. Weather is fetched automatically from Open-Meteo's free weather API. Optionally connect your own Ambient Weather Network (AWN) station for hyperlocal, on-farm data.

📁 YOUR DATA, YOUR DEVICE
No account. No sign-up. All field data is stored locally on your device. Export
any field — or your entire farm — to a JSON file for backup or transfer. Import
it on another device in seconds.

✅ DESIGNED FOR THE FIELD
• Works offline once weather data is loaded
• Dark mode support
• Fahrenheit / Celsius toggle
• Clean, fast interface built for quick daily checks

Whether you're timing a fungicide pass, watching for silk emergence, or planning harvest logistics, GDU Calculator gives you the numbers you need — right when you need them.