About Wattcalc
Wattcalc is a free, independent set of energy and sustainability calculators built for Australians. We focus on the practical questions households actually ask — will solar pay back, how much would an EV really cost me to run, and where can I cut my electricity bill?
What we do
We build clean, fast tools that use current Australian inputs and well-tested mathematics. Every calculator is reviewed against publicly available data — Australian Energy Regulator default market offers, ARENA published assumptions for residential solar, ATO running-cost conventions for vehicles, and Clean Energy Council guidance on system performance.
- Solar payback using your system size, daily usage, self-consumption, retail rate and feed-in tariff.
- EV vs petrol cost of ownership across fuel/electricity, servicing and time.
- Plain-English articles that link back to the calculators, so the maths is always one click away.
How we make money
Wattcalc is funded by display advertising. We do not sell solar systems, EVs, batteries or electricity plans. We do not sell or share your data, and we don't earn referral fees or commissions from installers, dealers or retailers. The numbers you see are not influenced by who pays us.
Important: this is not advice
The calculators on Wattcalc provide general estimates only. They are not financial advice, energy advice or product recommendations, and they don't consider your specific roof, vehicle, tariff structure or household circumstances. Please read our full disclaimer, get quotes from accredited installers or dealers, and speak to a licensed adviser before making any major energy or vehicle decision.
Contact
If you have feedback, spot an error in a calculator, or want to suggest a new tool, please email hello@wattcalc.com.au. We read every message.