Energy field notes / Calculator
Oncor demand ratchet calculator
Oncor's tariff can bill a larger Texas business site on 80% of its highest peak from the past 11 months, even in a quiet month. This calculator applies the tariff's rules to two numbers from your bills, so you can see which demand this month's delivery charges are priced on.
By Wire & Watt Published Updated
Calculator
What demand will Oncor bill this month?
For a site on Oncor’s Secondary Service Greater Than 10 kW rate. Read the numbers from the demand lines on your bill. Nothing you enter leaves this page.
The highest 15-minute demand on this bill (NCP kW).
The largest monthly peak before this month.
Enter both peaks to see the result.
The rules it applies.
These come from Oncor’s Tariff for Retail Delivery Service for Secondary Service Greater Than 10 kW (revision 12, effective June 1, 2026).
- Peak demand (NCP kW) is the kW supplied in the 15-minute period of highest use in the billing month.
- Distribution System Charge: if the highest peak in the previous 11 months was 20 kW or less, or the annual load factor is 25% or less, Oncor bills this month’s peak. Otherwise it bills the higher of this month’s peak and 80% of the highest peak in the previous 11 months.
- Riders NDC, DCRF, RCE, ISR and MG always use the higher of this month’s peak and 80% of the highest peak in the previous 11 months.
- Annual load factor is the kWh used in the 12 billing months ending in December, divided by the highest peak in those months times the days in the billing periods times 24. It applies for the next 12 billing months. With less than 90 days of history, Oncor treats it as above 25%.
- Above 20 kW, the distribution price per kW depends on the load factor band: highest at 0% to 10%, stepping down through 11% to 15%, 16% to 20% and 21% to 25%, lowest at 26% and above.
The 25% load factor exemption matches the Public Utility Commission of Texas rule that a demand ratchet may not apply to nonresidential secondary customers with a load factor of 25% or less. Our guide to Oncor delivery charges explains each charge.
Where to find the numbers.
Your bill may show peak demand as kW, demand or billing demand. If it shows both a metered (actual) demand and a billed demand, a billed figure above the metered one means a higher billing demand was applied, such as the ratchet. For the annual load factor, add up the kWh on the twelve bills from January to December and note the highest peak among them.
What it does not do.
It shows which kW the charges are billed on, not what they cost: prices change from time to time and are in Oncor’s tariff. It does not cover 4CP, which applies to sites that have reached 700 kW. It applies to Oncor only; CenterPoint bills its distribution charge on the current month’s peak in kVA (see our CenterPoint guide). Your bill and Oncor’s tariff decide what you actually pay.
Comparing supply offers for an Oncor-area site? Start with your ZIP and add your bill when you have it.
Sources and scope
Supplier explanations support the general contract and billing points in this guide. Your own agreement and service location determine the terms that apply to you.
Wire & Watt wrote this guide from the sources below. No supplier or utility paid for it or reviewed it. The supplier a business chooses pays us, never the business: how we’re paid.
- Oncor Tariff for Retail Delivery Service, 6.1.1.1.2 and 6.1.1.1.3 (revision 12, effective June 1, 2026) (opens in a new tab)
- Oncor: Delivery Charges 101 (residential and secondary services) (opens in a new tab)
- Texas PUC Substantive Rule 25.244: billing demand for certain utility customers (opens in a new tab)