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Free Engineering Calculators

The same calculators our engineering team uses.

The same calculators we built for ourselves, opened up for anyone planning a battery project. Get to a sensible first number in a couple of minutes, before you talk to a salesperson.

4
Free calculators
$0
Always free
400+
Projects we've sized
~2 min
Per calculation

Size and pick the right product

Before you quote
The math you do before quoting a project: how much capacity you actually need, which product line fits, and how long it'll back up the load.
Live
For technical buyers

C-rate Calculator

Enter any two of capacity, continuous power and discharge run-time; the tool solves the third and reads out what the C-rate means for cell and cooling choice.

You enterAny two of kWh, kW, run-time
You getC-rate + power + run-time, with interpretation
Open calculator
Live
For homeowners & installers

Battery Backup Duration

Settle the "how many hours will this last in an outage" question before you commit to a battery size.

You enterBattery kWh + load profile
You getHours of backup at full / partial load
Open calculator
Want to understand the trade-offs behind these numbers? Our sizing guides for C&I, utility-scale and residential walk through the same logic in long form.
Open the sizing guides

Run the money math

Make the case
Payback, levelized cost, layered revenue and tax credits: the numbers that decide whether a project moves forward or sits in someone's drawer for another year.
Live
For commercial operators

Demand-Charge Savings

Estimate the demand-charge reduction you can capture from peak shaving: usually the fastest payback layer for a C&I battery.

You enterPeak kW, demand rate, battery power + energy
You getShaved kW + monthly / annual $ saved
Open calculator
If you want the reasoning behind the math: LCOS explained, retrofit ROI analysis, and frequency revenue stacking are written up at length on the blog.
Read the financial guides

Quick lookups

Daily reference
Unit conversion and compatibility checks: the small calculations that come up every day on a job site or in a spec review.
Live
For everyone

Ah <-> kWh Converter

Convert between amp-hours and kilowatt-hours at any battery voltage: the conversion you'll do a hundred times this year.

You enterAh (or kWh) + battery voltage
You getkWh (or Ah) instantly
Open calculator
New to the basics? The Knowledge Base defines every term these calculators ask about.
Open the Knowledge Base
When the calculator gets you close enough

Send us your numbers. We will size the system properly.

Run the calculator that fits your project, then send us the inputs. An engineer will check the sizing, recommend the right product line and come back with pricing.

Send your inputs to engineeringRead the guides first

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