What inputs do I need?

Pick an appliance preset or add a custom one. Set power (W) and usage (hours/day & days/week) or use kWh/cycle with cycles/week. Optionally add standby power and quantity.

How are costs and CO₂ calculated?

Annual kWh × tariff gives cost; annual kWh × grid intensity (kg CO₂/kWh) gives CO₂. You can edit tariff, currency, and grid intensity.

Does it upload my data?

No. Everything runs locally in your browser. No appliance details are sent to a server.

Home Energy Usage Calculator — kWh, Cost & CO₂

Friendly estimates for planning and awareness. Private by design — runs locally in your browser.

Household & Tariff

Currency symbol Tariff (per kWh) Grid intensity (kg CO₂ / kWh) Weeks per year

Appliances

Add preset

Tip: For always-on devices (fridge, routers), set hours/day to 24 and days/week to 7, or use an average Watt value. For cycle-based devices (washer, dryer, dishwasher), use the cycle tab.

Results

How This Home Energy Calculator Works

Add appliances via presets or custom entries, then set power and usage. The calculator converts power × time (or kWh per cycle) into annual kWh, then multiplies by your tariff and grid intensity to show cost and CO₂. Everything is editable and runs locally in your browser.

Two simple input styles

Time-based: Watts × hours/day × days/week × 52 weeks → kWh/year.
Cycle-based: kWh/cycle × cycles/week × 52 weeks → kWh/year.

Assumptions & notes

Presets are lightweight, awareness-level defaults; adjust to your devices.
Grid intensity and tariffs vary by region/time. Both are editable.
Heat pump option lets you enter required heat (kWh) and COP to estimate electric kWh.

FAQs

What if I only know annual kWh from the label?

Add a custom item and switch to the cycle tab using 1 cycle/week with kWh/cycle = annual kWh ÷ 52, or use the time tab with hours and Watts that match the label.

How do I include standby?

Use the standby Watts field and set hours/day it’s in standby. Standby is added on top of active use.

Can I change the currency?

Yes—set the currency symbol (e.g., £, $, €, ₹). Tariff is per kWh in that currency.