Calculator Inputs
Example Data Table
| Scenario | Fuel | Power | Time (cook+preheat) | Efficiency | Energy (kWh equiv.) | Cost/session |
|---|---|---|---|---|---|---|
| Roasted garden vegetables | Electric | 2.4 kW | 55 min | 0.85 | ~2.59 | Depends on your tariff |
| Batch canning day | Gas | 12,000 BTU/h | 90 min | 0.80 | ~6.59 | Depends on your unit price |
| Quick air fryer meal | Electric | 1,800 W | 25 min | 0.90 | ~0.83 | Depends on your tariff |
These rows show typical inputs, not fixed outcomes.
Formula Used
Core energy
Total hours = (Cook minutes + Preheat minutes) ÷ 60
Rated kW = input converted to kW
Average kW = Rated kW × Average power factor (optional)
Active kWh = (Average kW × Total hours) ÷ Efficiency
Standby kWh = (Standby W ÷ 1000) × Total hours
Total kWh (equiv.) = Active kWh + Standby kWh
Cost and conversions
Electric cost = Total kWh × Price per kWh
Gas therms = Total kWh ÷ 29.300111
Gas MJ = Total kWh × 3.6
Gas m³ ≈ Total kWh ÷ 10.55
Gas cost = Gas units × Price per unit
Per serving = Session cost ÷ Servings
Monthly ≈ Weekly × 4.345, Yearly = Weekly × 52
Efficiency captures heat losses and real-world cycling. Use average mode when thermostats or pulsed heaters reduce continuous draw.
How to Use This Calculator
- Pick your energy source and choose a power unit.
- Enter rated power from the appliance label plate.
- If heat cycles on and off, switch to average mode.
- Add cook time, preheat time, and any standby draw.
- Set efficiency and your local price for electricity or gas.
- Enter servings and weekly frequency for projections.
- Press calculate to view results and download files.