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Know your energy costs — and cut them.
Thirty-one instant calculators that answer the questions behind every power bill: what it costs, what's driving it, and whether solar, a heat pump, an EV, or backup power would actually pay off.
Estimated monthly bill
$127.50
Usage 850 kWh / month
Rate $0.15 / kWh
Per year $1,530
Try it with your numbers →Step one
Bills & Home
Find out exactly what you're paying for electricity — which appliances drive the number up, and whether a better plan or a heat pump would change it.
Electricity Bill Calculator
Estimate your monthly and yearly bill from usage and rate — or build it appliance by appliance.
Open calculator →Appliance Running Cost
What any appliance costs per day, month, and year — with presets for 15 common devices.
Open calculator →AC / Heater Running Cost
The real cost of cooling and heating — by watts or BTU, duty cycle included.
Open calculator → NewBTU / AC Size Calculator
The air conditioner size your room actually needs — BTU, tons, and kW.
Open calculator → NewHeat Pump Savings
Heat pump vs gas, oil, propane, or electric — annual savings at your prices.
Open calculator → NewPC Power Cost
Gaming rig, office PC, or laptop — what it adds to the bill, idle time included.
Open calculator →kWh Cost Calculator
Convert units to cost — or a budget back into kWh. Both directions, any currency.
Open calculator →Phantom Load Calculator
What your always-on devices quietly cost per year — and what unplugging saves.
Open calculator →Compare Electricity Plans
Two tariffs side by side: which is cheaper at your usage, and the yearly switch savings.
Open calculator →Step two
Solar & Battery
Work out whether solar pays off — savings, payback, ROI — and size every part of the system: panels, battery, charger, and inverter.
Solar Savings & Payback
Annual savings, payback period, and 25-year returns — then compare real installer quotes.
Open calculator →Solar Panel Size
The system size, panel count, and roof area you need to cover your usage.
Open calculator →Solar Battery Size
The battery capacity (kWh and Ah) to ride out outages or nights off-grid.
Open calculator →Solar ROI / Break-even
Break-even year, lifetime profit, and total return — with rate inflation built in.
Open calculator →Off-Grid Solar System
A full kit spec — array, panels, battery bank, and inverter — from your daily kWh.
Open calculator →Solar Output Estimator
Daily, monthly, and yearly kWh any system will produce where you live.
Open calculator → NewBattery Charge Time
How long any battery takes to charge — from capacity, charger power, and losses.
Open calculator → NewAh to Wh Converter
Amp-hours ↔ watt-hours at any voltage — the honest way to compare batteries.
Open calculator → NewInverter Size
Continuous watts, surge rating, and battery draw — the inverter that fits your loads.
Open calculator →On the road & off the grid
EV & Backup Power
Charge the car and keep the lights on — cost, time, and sizing numbers for drivers and outage-proofers.
EV Charging Cost
Cost per charge, per mile, and per month — home vs public charging.
Open calculator → NewEV Charging Time
Level 1, Level 2, or DC fast — how long the charge takes and range added per hour.
Open calculator → NewTesla Charging Cost
Model-specific costs — per charge, per mile, and per month, home or Supercharger.
Open calculator →Generator Size
Add up your appliances and get the right generator size, startup surge included.
Open calculator →UPS / Battery Runtime
How long your UPS or power station lasts at any load — losses included.
Open calculator →Trade & DIY tools
Electrical
The conversions and sizing rules that keep planning numbers honest — watts, amps, kVA, breakers, wire, and voltage drop.
Watts to Amps
Convert watts ↔ amps for DC, single-phase, and three-phase — with power factor.
Open calculator → NewAmps to Watts
Current to power for any circuit type — with a quick-reference table.
Open calculator → NewkW to Amps
Kilowatts to current at any voltage — plus the breaker that load needs.
Open calculator → NewkVA to kW
Apparent ↔ real power with power factor — for generators and transformers.
Open calculator → NewOhm's Law Calculator
Enter any two of volts, amps, ohms, watts — get the other two instantly.
Open calculator → NewBreaker Size
The right circuit breaker for any load — 125% rule and matching wire gauge.
Open calculator →Wire Size Calculator
The minimum cable size (mm² / AWG) that keeps voltage drop in limits.
Open calculator →Voltage Drop Calculator
Volts lost over any run — and whether it stays inside the 3% guideline.
Open calculator →How people use it
The path to a lower bill
Each calculator feeds the next — start with what you pay today and end with a plan.
Learn the numbers
Guides
Number-driven guides that pair with the calculators — every claim priced out.
Appliance Wattage Chart
Running watts, surge watts, and monthly kWh for 60+ appliances.
Read the guide →How to Lower Your Electric Bill
Twelve fixes ranked by real dollar impact, not by ease.
Read the guide →How Many Solar Panels Do I Need?
From your monthly kWh to a panel count in three steps.
Read the guide →Free energy calculators that actually help you save
MyEnergyToolkit is a free suite of 31 electricity and solar calculators built to answer the questions behind every power bill: What is this costing me? What's driving it? And would solar, a heat pump, an EV, or backup power actually pay off? Every tool runs instantly in your browser — no account, no app, no data sent anywhere. Start with your electricity bill, drill into the appliances behind it, then see what solar could save you — and if you're wiring something up, the electrical tools keep your planning numbers honest.