TryBuildCalcElectricity Running Cost Calculator (Day / Week / Month / Year Cost Estimate)
Calculate running cost instantly.
🕒 Last updated: August 28, 2026
Inputs
Equipment
Pick a preset for a typical starting point, or choose Custom and enter your equipment's actual nameplate watts and usage pattern.
Equipment 1
ℹ️For equipment that draws a small amount of power even when off but still plugged in.
Equipment 2
ℹ️For equipment that draws a small amount of power even when off but still plugged in.
Equipment 3
ℹ️For equipment that draws a small amount of power even when off but still plugged in.
Electricity Rate
ℹ️Found on your utility bill — sometimes called the energy charge or price per unit (1 unit = 1 kWh).
ℹ️A fixed monthly fee your utility charges regardless of usage — include it for a full bill estimate, leave blank to see energy cost only.
Estimated Monthly Cost: $127.15
From 847.68 kWh/month at $0.1500/kWh
Cost by Period (Energy Only)
| Period | kWh | Cost |
|---|---|---|
| Day | 27.85 | $4.18 |
| Week | 194.95 | $29.24 |
| Month | 847.68 | $127.15 |
| Year | 10,172.21 | $1,525.83 |
Equipment Breakdown (Monthly)
| Equipment | kWh | Cost | Share |
|---|---|---|---|
| Refrigerator | 109.58 | $16.44 | 12.9% |
| Central A/C | 730.50 | $109.58 | 86.2% |
| LED Bulb | 7.61 | $1.14 | 0.9% |
Assumptions Used
Month = 30.4375 days (365.25 ÷ 12) average, year = 365.25 days — avoids a lumpy figure tied to any one calendar month. Uses a flat electricity rate, not tiered or time-of-use pricing. This is a reference estimate — confirm against your actual utility bill and rate structure.
Planning backup power instead of running cost? UPS Battery Capacity Calculator →
Sizing a generator for this same equipment list instead? Generator Size Calculator →
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Electricity Running Cost Calculator.
General electricity running cost estimate
This page gives the full combined result — energy consumption and cost broken down by day, week, month, and year, plus a per-equipment breakdown — from one set of equipment and rate inputs.
It's the same calculator behind every other running-cost variant on this site, just without a specific scenario pre-selected — useful for a general check before finalizing your actual equipment list.
- Add up to 25 pieces of equipment, each with its own hours/day and days/week.
- Accounts for standby/phantom power for equipment left plugged in.
- Shows cost share per item, so you can see what's really driving your bill.
Running Cost Formula: How Is It Calculated?
The core formula converts power (watts) and time (hours) into energy (kilowatt-hours), then applies your electricity rate.
Step 1 — Weekly Active Energy
Active kWh/week = (Watts × Quantity × Hours/Day × Days/Week) ÷ 1,000
This is the energy consumed while the equipment is actively running.
Step 2 — Weekly Standby Energy (Optional)
Standby Hours/Week = (24 × 7) − (Hours/Day × Days/Week)
Standby kWh/week = (Standby Watts × Quantity × Standby Hours/Week) ÷ 1,000
For equipment left plugged in, this adds the phantom-load energy consumed during all the hours it's not actively running.
Step 3 — Cost by Period
Weekly Cost = (Active kWh + Standby kWh) × Rate per kWh
Daily = Weekly ÷ 7, Monthly = Daily × 30.4375, Yearly = Daily × 365.25
Every equipment row's cost is summed together, and an optional monthly service charge is added on top to estimate a full bill.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Equipment | 3 items | Sets total energy consumption |
| Rate | $0.1500/kWh | Converts kWh to cost |
| Service Charge | None | Adds a fixed fee to the total bill estimate |
Step 1 — Weekly Energy per Equipment
Each row's active-hours energy is (Watts × Quantity × Hours/Day × Days/Week) ÷ 1,000. Any standby watts add energy for the remaining hours in the week (168 total).
| Equipment | Active Calculation | Standby Calculation | Weekly kWh |
|---|---|---|---|
| Refrigerator | 150W × 1 × 24h × 7d ÷ 1000 = 25.20 kWh | — | 25.20 |
| Central A/C | 3000W × 1 × 8h × 7d ÷ 1000 = 168.00 kWh | — | 168.00 |
| LED Bulb | 10W × 5 × 5h × 7d ÷ 1000 = 1.75 kWh | — | 1.75 |
Step 2 — Total Energy by Period
Every row's weekly kWh is summed, then converted: Daily = Weekly ÷ 7, Monthly = Daily × 30.4375, Yearly = Daily × 365.25.
| Period | Calculation | Total kWh |
|---|---|---|
| Week | 25.20 + 168.00 + 1.75 | 194.95 |
| Day | 194.95 ÷ 7 | 27.85 |
| Month | 27.85 × 30.4375 | 847.68 |
| Year | 27.85 × 365.25 | 10,172.21 |
Step 3 — Cost by Period
Each period's total kWh is multiplied by your electricity rate ($0.1500/kWh).
| Period | Calculation | Energy Cost |
|---|---|---|
| Day | 27.85 × $0.1500 | $4.18 |
| Month | 847.68 × $0.1500 | $127.15 |
| Year | 10,172.21 × $0.1500 | $1,525.83 |
Therefore, at $0.1500/kWh, your equipment costs approximately $127.15 per month ($1,525.83 per year) to run.
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Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.