About MiniSplitSizer

Hi, I’m Mostapha.
Welcome to MiniSplitSizer.com. If you are here, you are probably frustrated.
You are likely staring at a confusing chart on a manufacturer’s website, trying to figure out if you need a 12k or an 18k unit. You have read forum posts that contradict each other. You have contractors quoting you $5,000 for a job you know you can do yourself for $1,500.
I built this website because I was exactly where you are.
The Story Behind the Calculator
A few years ago, I decided to install a mini split in my own garage workshop. I searched Google for “what size do I need?” and found five different websites giving me five different answers.
One said 9,000 BTU. Another said 24,000 BTU. I guessed (wrongly), bought a unit that was too small, and spent the entire summer sweating in a room that never got below 80 degrees.
I realized that “Square Footage” is not enough. You cannot size an AC based on floor space alone. You have to account for:
Ceiling height (Volume).
Insulation quality (R-Value).
Climate zone.
Sun exposure.
So, I decided to solve this problem once and for all. I combined engineering standards (Manual J principles) with real-world DIY data to build the Mini Split Sizing Calculator.
Our Mission
Our goal is simple: To empower the DIY homeowner.
We believe that high-efficiency comfort shouldn’t cost a fortune. Whether you are installing a MrCool DIY in your bedroom, a Pioneer in your mobile home, or a Mitsubishi in your office, we want to ensure you buy the right machine the first time.
Why Trust Us?
We are Independent: We are not owned by any HVAC brand. If a unit has a bad warranty or hard installation, we will tell you.
We are Data-Driven: Our recommendations are based on math, not sales quotas.
We are Real People: We answer comments, update our guides, and actually care if your house is cool.
Ready to Start?
Don’t make the same mistake I did. Stop guessing and start calculating.
👉 Use the Calculator Now

Contact Us Have a specific question or found a bug in the calculator? Email us at: support@minisplitsizer.com

Services
We Provide

Services We Provide

Bringing Engineering-Grade Accuracy to Every DIY Project.

Welcome to MiniSplitSizer.com. We believe that professional-grade home comfort shouldn’t require a professional-grade budget.

Check How We calculate!

Our best mini split size calculator.

Our Mission

Our mission is simple: To empower homeowners to take control of their comfort. We want to make sure that when you invest in a system like MrCool or Pioneer, you get it right the first time. No guessing, no sweating, just perfect climate control.

The idea for this tool was born from a simple observation: thousands of homeowners were buying the wrong size mini splits. Some followed outdated “rule of thumb” advice and ended up with units that were too small to handle a heatwave. Others bought massive, oversized units that short-cycled and failed to dehumidify their homes. We created MiniSplitSizer to bridge the gap. We built a free, accessible tool that uses the principles of Manual J Load Calculation—the gold standard in the HVAC industry—to give DIY enthusiasts a precise, data-backed recommendation in seconds..

Calculate Your Size

Don’t guess! Use our free tool to find the exact BTU load for your specific room dimensions.

Pick the Right Unit

Compare top-rated DIY brands like MrCool & Pioneer. Get the best features for your budget.

Install & Chill

Follow our installation guides, set up your system, and enjoy efficient cooling all year round.

Our Tool

Why Trust Our Calculations?

Unlike generic calculators that simply multiply your square footage by a random number, our algorithm considers the critical factors that actually affect heat load:

Ceiling Height:

Because heating a room with cathedral ceilings requires significantly more power.

Solar Exposure:

We account for the thermal gain from windows in sunny climates.

Insulation Quality:

We adjust recommendations for older homes versus modern, energy-efficient builds.