Free Off-Grid System Calculators & Tools
Plan your off-grid energy system with confidence. Our free calculators cover cable sizing, voltage drop, battery banks, solar yield, and fuse ratings — everything you need for a safe, efficient installation.
Calculators
Individual tools for planning specific aspects of your installation
DC Voltage Drop Calculator
Calculate voltage drop across DC cable runs in your off-grid energy system. Check if your wiring meets the recommended 3% threshold.
Open CalculatorBattery Bank Sizing Calculator
Determine the right battery bank capacity based on daily consumption, autonomy days, and depth of discharge for lithium and lead-acid batteries.
Open CalculatorSolar Panel Yield Estimator
Estimate energy output from solar panels at any UK location. Get seasonal breakdowns and recommended MPPT charge controllers.
Open CalculatorCable Sizing Guide
Find the minimum cable cross-section area for your DC installation. Enter current draw and cable length for the recommended cable size.
Open CalculatorFuse Sizing Calculator
Calculate the correct fuse or circuit breaker rating for your DC cables. Fuses protect cables from overheating and should be sized correctly.
Open CalculatorOff-Grid AI Assistant
Ask any question about off-grid products — specifications, sizing, installation, compatibility, and more. AI-powered answers from our comprehensive database.
Open CalculatorWhy Use Our Calculators?
Designed specifically for off-grid energy system installations
Safety First
Correctly sized cables and fuses prevent overheating, fire risk, and equipment damage. Our tools help you get it right the first time.
System-Optimised
Calculations are tuned for equipment thresholds, including the 3% voltage drop recommendation for inverters and chargers.
Works Everywhere
All calculators run entirely in your browser. No app to install, no account required, and fully usable on mobile, tablet, or desktop.
Save Money
Right-sizing your components avoids overspending on oversized cables and batteries, or the costly mistakes of undersized parts.
Frequently Asked Questions
Are these calculators free to use?
Yes, all calculators and tools on Off Grid 4 Less are completely free. They are designed to help you plan and optimise your off-grid energy system without any cost.
Do I need to create an account to use the tools?
No account is required. All tools work directly in your browser with no sign-up or login needed.
Are the calculations accurate?
Our calculators use industry-standard electrical formulas and are tailored for DC systems commonly used with Victron Energy products. They provide reliable estimates, though we always recommend consulting a qualified installer for critical installations.