Mortgage Calculators (8 tools)
P&I, PITI budget, affordability, amortization, extra payments, rent vs. buy, refinance, and bi-weekly.
Open CalculatorsFree efficiency and finance calculators with transparent formulas, live results, and practical tips. Pick a category below — every tool updates as you type.
Mortgage & home buying
Run the numbers before you make an offer — monthly P&I, full PITI budget, affordability limits, amortization schedules, extra payments, rent vs. buy, refinance break-even, and bi-weekly payoff. Built for U.S. fixed-rate loans with clear breakdowns.
Home energy & HVAC
Model real utility savings on upgrades homeowners actually debate — heat pump water heaters, window A/C and film, attic insulation R-value, pool pump variable speed, refrigerator replacement, ventless dryers, whole-house fans, well pump short-cycling, dehumidifiers, and space heater vs central heat.
Water Heater Efficiency
Compare electric coil, heat pump, gas & propane annual costs with payback analysis.
Open CalculatorWindow A/C Upgrade
CEER degradation, sizing check, annual kWh & payback for a modern replacement unit.
Open CalculatorSpace Heater vs Central
Zone heating with thermostat setback vs full-home furnace — daily, monthly & tipping point.
Open CalculatorPool Pump Savings
Affinity-law VS pump savings — kWh comparison, payback months & 5-year projection.
Open CalculatorDehumidifier Sizing
Pints per day by dampness level — legacy vs Energy Star annual running cost.
Open CalculatorRefrigerator Replacement
Age degradation, garage penalty & keep vs scrap recommendation with payback.
Open CalculatorClothes Dryer Heat Pump
Vented vs ventless energy, HVAC makeup-air penalty & multi-year upgrade ROI.
Open CalculatorWindow Film Solar ROI
SHGC reduction, blocked radiant BTUs, avoided A/C kWh & payback season gauge.
Open CalculatorAttic Insulation Payback
R-value upgrade, Fourier heat transfer contraction & HVAC break-even years.
Open CalculatorWhole-House Fan vs A/C
Shoulder-season evening ventilation vs central A/C — daily, monthly & seasonal savings.
Open CalculatorWell Pump Short-Cycling
Pressure tank surge waste, monthly bill impact & pump failure risk meter.
Open CalculatorAuto & electric vehicles
Car loan payments with tax and fees, plus Level 1 vs Level 2 home charging efficiency — charge time, grid kWh waste from thermal loss, and 240V install payback in months.
Car Loan Calculator
Monthly auto payment with sales tax, fees, trade-in, and amortization schedule.
Open CalculatorEV Level 1 vs Level 2
Charging efficiency, daily charge time & 240V install payback in months.
Open CalculatorLowering for MPG & EV Range
Aero drag savings by speed, drop height, and vehicle type — gas and kWh.
Open CalculatorInvesting & compound growth
Project long-term savings with monthly contributions — compound interest with flexible compounding frequency and SIP / mutual fund corpus estimates with optional step-ups.
SIP / Mutual Fund Calculator
Project corpus value for monthly SIPs with optional lump sum and annual step-up contributions.
Open CalculatorCompound Interest Calculator
Future value with adjustable compounding frequency and optional monthly deposits.
Open CalculatorEveryday math & utilities
Quick homework and life-admin helpers — percentages, fractions, square footage, age in days, and overtime gross pay. All update live with no submit button.
Percentage Calculator
What is X% of Y, reverse percentages, percent change, and add/subtract — four modes on one page.
Open CalculatorSquare Footage Calculator
Rectangle and multi-room area totals with sq ft ↔ sq m conversion.
Open CalculatorAge Calculator
Exact age in years, months, and days — plus total days lived and next birthday.
Open CalculatorFraction Calculator
Add, subtract, multiply, divide, and simplify fractions with decimal results.
Open CalculatorOvertime Calculator
Gross pay with regular and OT hours, multiplier, and annual estimate.
Open Calculator
Our standard: If a calculator can't show its work, it doesn't ship. These are planning tools — not financial, tax, or legal advice.