About WattMath
Making energy decisions easier with free, accurate, and transparent calculators.
Our Mission
WattMath exists to democratize energy calculations. Whether you're a homeowner considering solar panels, a facility manager planning an LED retrofit, or an engineer sizing a generator, you deserve access to accurate, easy-to-use tools—without paywalls, sales pitches, or hidden agendas.
Why We Built This
Making informed energy decisions is hard. The math is complex, variables are numerous, and most online calculators are either overly simplistic or designed to sell you something. We wanted to create something different: tools that are accurate enough for professionals, accessible enough for homeowners, and transparent enough for everyone.
Our Principles
Transparency
Every calculator shows the formulas and assumptions we use. There's no black box—you can verify our math, understand our methodology, and adjust inputs to match your specific situation.
Accuracy Over Simplicity
We include the factors that matter: panel degradation in solar calculations, motor starting loads in generator sizing, zone heating considerations in space heater comparisons. Our tools give you a realistic picture, not an optimistic sales pitch.
No Bias
We don't sell solar panels, HVAC systems, or energy audits. Our calculators will tell you when an investment doesn't make sense just as readily as when it does. Your outcome is our only interest.
Forever Free
All calculators are free to use, with no account required. We believe access to good information shouldn't have a price tag.
Who Uses WattMath
- Homeowners evaluating solar, heat pumps, or appliance upgrades
- Renters analyzing space heaters and vampire loads
- Small business owners planning lighting retrofits
- Facility managers calculating steam pipe insulation ROI
- Engineers double-checking motor calculations
- Energy auditors providing quick estimates to clients
- Students learning energy engineering concepts
Get in Touch
Have a question, suggestion, or found an error? We'd love to hear from you. Visit our contact page to get in touch.
Want to suggest a new calculator? Let us know what energy calculation would be most helpful—we're always expanding our toolkit based on user feedback.