Tariff audit
See the charge stack instead of hiding fixed fees, taxes, demand charges or credits inside one number.
OneFreePlace · Tool #148
Calculate electricity cost from the tariff you actually pay.
Price one appliance, a whole equipment list, or rebuild an electricity bill. Model flat, tiered and time-of-use rates; keep fixed charges separate from marginal appliance cost; include standing charges, demand charges, tax and export credit; and see exactly where every cent comes from.
✓ Flat / tiered / TOU tariffs✓ Duty-cycle + standby
✓ Marginal tier pricing✓ Demand + standing charges
✓ Bill reconciliation
Electricity Cost Calculator
appliance · portfolio · bill lab · marginal pricing
What are you costing?
Start with the load, then price it with the tariff.
Appliance energy modelDuty cycle applies inside the scheduled on-window; standby applies outside that window.
Tariff structureEnter rates from your tariff or bill. No country-average rate is silently substituted.
In appliance/equipment modes, baseline usage lets the calculator price only the added load at the correct marginal tiers. In Bill mode, tiers are applied directly to billed usage. The rate-entry scale applies to energy, standing/day, demand and export rates; fixed monthly charges, adjustments and minimum bills stay in main currency units.
Bill-only charges and creditsApplied only in Bill / tariff lab so fixed fees are not misleadingly attributed to one appliance.
Actual-bill comparison helps expose tariff riders or tax rules not represented by this model.
Optional carbon contextEnter your own grid factor; no region-specific emissions factor is assumed.
Energy use: kWh = watts × hours ÷ 1,000. Device modes show marginal energy cost; fixed charges belong to the whole bill and are included only in Bill / tariff lab.
Cost result
Calculating—
monthly electricity cost
Enter valid load and tariff inputs.
Energy use—billing-period consumption
Energy charge—before bill-only fixed charges
Effective rate—all modeled charges ÷ imported kWh
Daily / annualized—same usage pattern
Carbon context—only when a custom factor is entered
Rate opportunity—tariff-specific analysis
EstimateUse the exact tariff terms from your supplier for bill reconciliation.
Usage diagnostics
Appliance modes expose active versus standby energy; bill mode shows per-day usage and meter math.
Equipment breakdown
For a portfolio, see each load's monthly kWh and share. Single-appliance and bill modes show a one-row summary.
| Load | Power | Active kWh | Standby kWh | Total kWh | Share |
|---|
Tariff sensitivity
Flat, tiered and time-of-use pricing behave differently. These scenarios show what changes the marginal cost.
Bill reconstruction
Bill mode itemizes energy, standing/fixed charges, demand charges, adjustments, export credits, tax and any minimum-bill floor.
What makes real bills differ
Fixed and standing chargesThese are owed regardless of how much a single appliance runs, so this tool keeps them out of appliance marginal-cost estimates.
Bill-levelTier and time rulesUtilities may use monthly blocks, seasonal schedules, peak windows, or other conditions. Enter the structure printed on your tariff.
Tariff-specificDemand chargesSome commercial tariffs charge for peak kW demand as well as kWh energy. This is not the same as monthly energy consumption.
kW ≠ kWhi
Nameplate watts are not always average watts.Thermostats, compressors, variable-speed motors, chargers and power supplies can cycle or modulate. When accuracy matters, use a plug-in energy meter or utility data to measure real kWh, then enter that measured usage in Bill / tariff lab.