Actonnage Calculator
Free Actonnage Calculator for home & garden projects. Enter dimensions to get material lists and cost estimates. Get results you can export or share.
Formula
Tonnage = (Sq Ft x 20 BTU x Climate Factor x Insulation Factor x Height Adj) / 12,000
Start with a base of 20 BTU per square foot, then adjust for your climate zone, insulation quality, and ceiling height. Divide the total BTU requirement by 12,000 to convert to tons of cooling capacity. One ton of refrigeration equals 12,000 BTU per hour. Round up to the nearest standard AC unit size (1.5, 2, 2.5, 3, 3.5, 4, or 5 tons).
Worked Examples
Example 1: Standard Home in Warm Climate
Problem: Size an AC unit for a 1,500 sq ft home with 8 ft ceilings in a warm climate zone with average insulation.
Solution: Base BTU = 1,500 x 20 = 30,000\nClimate multiplier (warm) = 1.15\nInsulation multiplier (average) = 1.0\nTotal BTU = 30,000 x 1.15 = 34,500\nTonnage = 34,500 / 12,000 = 2.88 tons
Result: Recommended: 3-ton AC unit
Example 2: Large Home with High Ceilings
Problem: Size an AC unit for a 2,500 sq ft home with 10 ft ceilings in a hot climate with good insulation.
Solution: Base BTU = 2,500 x 20 = 50,000\nClimate multiplier (hot) = 1.3\nInsulation multiplier (good) = 0.85\nHeight adjustment = 1 + (10-8) x 0.125 = 1.25\nTotal BTU = 50,000 x 1.3 x 0.85 x 1.25 = 69,063\nTonnage = 69,063 / 12,000 = 5.76 tons
Result: Recommended: Two 3-ton units or one 5-ton unit with supplemental cooling
Frequently Asked Questions
Can I use Actonnage Calculator on a mobile device?
Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.
How accurate are the results from Actonnage Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Can I use the results for professional or academic purposes?
You may use the results for reference and educational purposes. For professional reports, academic papers, or critical decisions, we recommend verifying outputs against peer-reviewed sources or consulting a qualified expert in the relevant field.
What formula does Actonnage Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.