Your installer gave you one payback number at signing. SunTally shows you the real one — projected from a quote, or measured from your own utility bills. In your browser. For free.
Solar offsets the generation part of your electricity — but you still pay delivery and fixed fees no matter what. Net-metering terms change, rates inflate, and the panels degrade. So "is it paying off?" is genuinely hard to see. SunTally pulls the real signal out of the noise.
Payback year, lifetime net, and return on cost — from numbers you control, with honest assumptions you can change.
See exactly how much you pay the utility as a delivery company vs. a generation company. For many homes it's the majority.
No login, no upload, no server. Bills are parsed and stored in your browser. Open the source and verify it.
Considering solar, or checking a quote? Enter system cost, financing, your rates, and usage — or just drop in your proposal PDF and we'll read the numbers for you (in your browser). Get a 25-year projection: payback year, lifetime net, and where every future dollar goes.
Already have solar? Drop in your utility bills (PDF) or a CSV/Excel export. They're read into a local structured ledger you can edit, and the real dashboard builds itself — savings, coverage, and your effective rate over time.
Drop in your utility-bill PDFs and we'll read the numbers, import a CSV/Excel export, or paste rows by hand from the template — produced / delivered / sent-back kWh and charges.
Everything is normalized into a clean structured dataset that lives in your browser. Edit any cell; export to JSON or CSV anytime.
Cumulative payback, monthly savings, generation-vs-delivery split, effective rate, and seasonal coverage — the same analysis a spreadsheet nerd would build, instantly.
There is no backend. No account. No analytics on your data. Files are parsed locally and stored in your browser's own storage. It's open source — read every line and confirm it yourself.
SunTally is open source and will never charge users or sell data. It stays free because some of the people it helps choose to give back.
If this tool was worth it to you, an appropriate one-time donation to keep its development going would be really appreciated.
One way to think about it: paying a solar consultant to break all of this down and analyze it for you might be a ~$1,500 engagement. If the insight you got here felt worth $50, that's wonderful. If it felt worth $10, that's wonderful too. Pay what the clarity was worth to you.
Leave a tip →Want to clone SunTally and put it in front of your own customers? It's open source and runs on the honor system — you're welcome to.
If your company plans to use it commercially, the builder is happy to explore a simple licensing arrangement via a larger one-time contribution that funds continued development. Reach out and let's talk.
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