How to Estimate Your Monthly Electricity Usage
Last updated: 2 September 2026
Our plan comparison page gives you an accurate bill estimate once you enter your monthly usage in kWh — but if you don't know that number offhand, here are two ways to find or estimate it.
Option 1: Check your SP bill or account (most accurate)
Your actual monthly consumption in kWh is printed on every SP Group bill, and your online SP account shows a full history of past months. This is the most accurate figure to use, since it reflects your household's real usage pattern rather than an estimate.
Option 2: Estimate from your appliances
If you don't have a bill handy — for example, if you're moving into a new home — you can build a rough estimate using this formula for each appliance:
Estimated kWh per month = (wattage ÷ 1,000) × hours used per day × 30
For example, an air-conditioner rated at 1,000 W running 6 hours a night uses roughly (1,000 ÷ 1,000) × 6 × 30 = 180 kWh a month on its own. Add up the estimates for every appliance you use regularly to get a rough monthly total. Typical wattages for common appliances:
| Appliance | Typical wattage | Note |
|---|---|---|
| Air-conditioner (1 unit, split system) | 700–1,500 W | By far the biggest driver of usage in most SG homes — running one unit 8h/night uses roughly 170–360 kWh a month alone. |
| Storage water heater | 1,500–4,500 W | Instant/tankless heaters draw more power but only while running; storage heaters cycle on and off to maintain temperature. |
| Refrigerator | 100–200 W | Runs continuously, but only draws power in short cycles, not the full wattage 24/7. |
| Washing machine | 400–800 W | Only while running a cycle, typically under an hour. |
| Television | 80–150 W | Varies with screen size and type. |
| Standing/ceiling fan | 40–75 W | Cheap to run — a good substitute for aircon on cooler days. |
| Rice cooker / electric kettle | 500–1,500 W | High wattage but typically used for only minutes at a time. |
| LED lighting (per bulb) | 5–12 W | A full home's lighting usually adds up to only a few kWh a month. |
These are general ballpark figures — check the rating label on your own appliance for its actual wattage, since models vary.
Option 3: Use the home-type average as a starting point
If you'd rather not add up individual appliances, our comparison page also shows average monthly usage by home type (HDB flat size, condo, landed) sourced from the Energy Market Authority — a reasonable starting estimate if your household is fairly typical for your home type.