Understanding Peak-to-Average Ratio
How we calculate. PAR = peak demand ÷ average demand (dimensionless). See our methodology and accuracy policy .
Real-world scenario: A typical Peak-to-Average Ratio case uses peak load 10 and average load 6.5. Enter the same figures below to reproduce the worked path.
What is Peak-to-Average Ratio?
The inverse-style companion to load factor (PAR ≈ 100 ÷ load factor % when definitions match). Higher PAR means spikier demand.
- Same UOM for peak and average
- Result is a ratio, not a percent
- Pairs with load factor
The Formula
Worked Example
Common Use Cases
- Tariff analysis: peakiness
- Storage sizing: peak shaving need
- Demand response: spike magnitude
Pro Tips
- Use coincident peaks carefully
- State interval length
- Compare to load factor
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: Peak-to-Average Ratio results are educational energy and utilities planning aids—not engineering, grid-operations, or investment advice. Confirm definitions with your ISO/RTO, plant, and regulatory reporting standards.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
The worked example for peak to average ratio was verified with the calculator form on this page—enter the same values to confirm the result.
When to use this calculator
- Use this page when your wording matches peak to average ratio and the form labels on screen.
- Use percent of a number for “what is X% of Y?” problems.
- Use number is what percent when you know part and whole and need the percent.
Still unsure about peak to average ratio? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this peak to average ratio calculator?
For peak to average ratio, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for peak to average ratio—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking peak to average ratio, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For power system and plant performance concepts, consult: