tools · practical explainers
Useful tools, with the assumptions visible.
Small calculators and decision aids for questions that deserve more than a generic answer.
Each tool shows the inputs it uses, explains what the result means, and links to a fuller explainer. They are designed for orientation and comparison—not as a substitute for professional advice or a quote tailored to your situation.
Compound Interest Calculator
Estimate how an opening balance and regular contributions could grow over time.
Open tool →Solar Payback Calculator
Estimate simple solar-panel payback from system cost, incentives, annual output, and electricity price.
Open tool →Sunk Cost Decision Tool
Compare only the future costs and benefits of continuing, quitting, or choosing an alternative.
Open tool →Choose the right tool
Use the compound interest calculator to see the effect of time, recurring contributions, and an assumed return. Use the solar payback calculator to compare a system’s net cost with estimated bill savings. Use the sunk cost tool when a past investment is making it hard to judge the options in front of you.
Good tools do not hide uncertainty. Change the assumptions, compare realistic scenarios, and read the linked explainers before making a meaningful financial or purchasing decision.
These tools run in your browser and do not ask for an account. Start with the numbers you know, document the assumptions you do not know, and treat the output as a conversation starter—not a precise prediction.