Free · Private · Runs in your browser
Solar or a battery.
Worth it for you?
Use your own electricity history to see what solar, a battery, or both could save you.
Not with Tibber? Import a CSV or Excel file
- Free. No account with us, no sales calls.
- Calculated on your device.
- Your energy data isn’t stored by us. How it works
Built around your day
The same roof.
A different result.
Out all day or home by noon? When you use electricity changes how much solar you can use, and what a battery can save for later.
Tibber, connected
Read-only access to your consumption and price history.
Another provider, too
A CSV or Excel export, read in your browser. The file is never uploaded.
Hourly electricity
A day at home
A busy home at six.
Room for a few what-ifs
A little solar?
A bigger battery?
Try a different setup and follow its impact, from the yearly picture down to a single hour.
- 01
Choose your setup
Solar, a battery, or both.
- 02
Make it your own
Adjust sizes, costs and energy prices.
- 03
See if it pays off
Savings per year, when it pays for itself, and which size makes most sense.
Solar generation
A year of possibilities
Illustrative pattern · Your results depend on your home.
Why Wattklok exists
Curiosity
came first.
For the questions that come before an installation quote.
I wasn’t ready to buy.
I was just curious.I wanted to know if solar or a battery would pay off for my home. The calculators I tried wanted my contact details. I wanted an answer based on my own electricity use.
A few conversations (and beers) with a friend later, Wattklok took shape. Hopefully it helps you make up your own mind, too.
Free & local
A few things
worth knowing.
Wattklok is free, needs no account with us and works out the numbers in your browser. Here’s exactly what that means.
Is it really free?
Yes. There’s no subscription, no paid tier and nothing to unlock. We never ask for your name, email or phone number, so nobody will follow up with a sales call.
Where is my data processed?
On your device. Reading your file, building a profile and every simulation happen in your browser. Your history, settings and results are saved in this browser only, not on our servers, and stay there until you clear them.
Does anything pass through Wattklok’s servers?
Two things, and we keep neither. Tibber requires sign-in and data requests to go through a server, so ours passes your homes, history and prices straight on to your browser. Spot-price lookups send only your price area and dates. Weather and location search go directly from your browser to Open-Meteo and OpenStreetMap. We also count anonymous page views, without cookies. Your energy data is never part of that.
How should I use the estimates?
Compare your options, then check them against real installation quotes. Future prices, equipment performance and your household’s usage can change. Read how the calculations work
Over to you
What could change
for your home?
Free, no account with us, and your data is saved only in your browser.