Know what life really costs.
Thirty free calculators for energy, home, money, vehicles and small business. Change the assumptions, compare scenarios and understand the math behind the result.
Start with a real decision
Each calculator uses values you control and explains what is—and is not—included.
Electricity bill
Estimate a monthly electricity bill from power consumption and tariff.
Open calculator HomeMortgage payment
Calculate principal-and-interest monthly payments.
Open calculator MoneyHousehold budget
Estimate the monthly balance after living costs.
Open calculator VehicleFuel cost per month
Estimate monthly petrol or diesel costs.
Open calculator HomeRenovation budget
Estimate total project costs with contingency.
Open calculator BusinessBusiness break-even
Find how many units cover fixed costs.
Open calculatorOne place for everyday planning
Energy
Understand electricity, appliances, cooling, backup power, solar and EV charging with transparent formulas you can adjust.
7 toolsHome
Plan mortgage payments, housing cash flow, renovation, materials and moving costs with your own assumptions.
6 toolsMoney
Explore household budgets, emergency savings, goals, debt, subscriptions and purchasing power without creating an account.
5 toolsVehicle
Estimate fuel, finance, commuting, EV energy differences and total annual ownership costs.
4 toolsBusiness
Model break-even volume, gross margin, invoice totals and cash runway with straightforward arithmetic.
Useful without being opaque
The goal is not to tell you what to do. It is to make assumptions visible so you can see how a result changes.
Calculations stay in your browser
No account is required. Saved scenarios use your browser’s local storage rather than a SmartCostTools user database.
Every tool explains its formula
Each calculator includes the underlying logic, practical limitations and common questions so the number has context.
Change one assumption at a time
Use scenario testing to understand sensitivity instead of treating one estimate as a promise.
Evergreen planning guides
Short, practical explanations of the decisions behind the calculators.
How to estimate electricity costs without fooling yourself
A practical framework for turning watts, hours and tariffs into a realistic electricity-cost estimate.
Read guide →Energy guideSolar payback explained: what the simple number misses
Learn how simple payback works and why financing, maintenance and battery replacement can change the decision.
Read guide →Home guideMortgage payment math: principal, interest and the costs outside the formula
Understand what a mortgage calculator tells you—and what it leaves out of your housing budget.
Read guide →Home guideRent vs buy: separate cash flow from investment return
A clearer way to compare renting and ownership without pretending one annual number settles the decision.
Read guide →Home guideRenovation budgets: how to use contingency without hiding bad estimates
Build a renovation budget that separates known scope, uncertain scope and true contingency.
Read guide →Money guideEmergency funds: choose a target based on risk, not a slogan
A practical way to size an emergency reserve using essential expenses, income stability and household obligations.
Read guide →