About

How it's built,
and what we don't do.

A box volume calculator should be fast, accurate, and respect your privacy. Here's exactly what's under the hood.

Who runs this site

BoxVolumeCalculator.com is built and maintained by Sri Murugan Systems, an independent software practice in Madurai, Tamil Nadu, run by Murugan Vellaichamy. We build and operate a network of calculation and reference tools; this one is the site for boxes — volume in any unit, standard box sizes, dimensional weight by carrier, and packing geometry.

There is no editorial team and no sponsored content. Carrier rules are read off the carriers' own documents and dated, the DIM rule tracker shows every figure the site calculates with and where it came from, and corrections are welcome — the contact address is in the footer and on the contact page.

Methodology

Every dimension you enter is converted to SI base units (meters) before any calculation happens. This means a mixed input like "2 ft × 50 cm × 18 in" produces exactly the same result as if you'd converted everything to cm first by hand. Volume is then converted back to the unit you want to display.

Conversion factors are exact ratios from the International System of Units (SI): 1 inch = 0.0254 meters exactly, 1 foot = 0.3048 m, 1 US gallon = 0.003785411784 m³. We don't introduce rounding except at display time.

Dimensional weight

Dimensional-weight rules come only from each carrier’s own published documents — never from third-party summaries. FedEx, UPS, USPS, DHL, Parcelforce and Amazon FBA figures were last verified on 22 September 2026. Current values used:

FedEx (inches, US & intl): 139 in³/lb
UPS Daily Rates (US): 139 in³/lb
UPS Retail Rates (US): 166 in³/lb
FedEx / UPS (metric, intl): 5,000 cm³/kg
USPS Priority Mail, Priority Mail Express,
Ground Advantage, Parcel Select: 139 in³/lb, parcels over 1 ft³ only
DHL Express (from the US): 139 in³/lb (5,000 cm³/kg outside the US)
Parcelforce Worldwide (intl): 5,000 cm³/kg
Air freight (1:6 ratio): 6,000 cm³/kg

Rules verified 22 Sep 2026 · sources: FedEx Service Guide 2026 · UPS 2026 Rate and Service Guide (Daily Rates) · UPS 2026 Rate and Service Guide (Retail Rates) · USPS DMM 223 (Priority Mail: DIM weight, cubic, nonstandard fees) · DHL Express US Service & Rate Guide 2026 · DHL — How to calculate volumetric weight · Parcelforce — measuring international parcels · DHL Global Forwarding — calculating chargeable weights

Always check your own rate sheet or carrier account before relying on a figure for billing — carriers change these rules, usually in January and July. When we update a value, we change the “Rules verified” date shown on the shipping pages.

Accuracy & rounding

Calculations run at full double-precision floating point (about 15 significant digits). Display values are rounded for readability:

Privacy

The calculator itself runs entirely in your browser. We don't send your inputs (dimensions, units, results) to any server, and we don't store them. There are no accounts, no logins.

To keep the site free, we use a few third-party services: Google Analytics for traffic measurement, and Google AdSense and Adsterra for advertising. These services may set cookies and process limited information about your visit (pages viewed, approximate location, device type) according to their own privacy policies.

For full details and opt-out instructions, see our privacy policy.

The "Share link" feature works by encoding your inputs into the URL itself (e.g. ?l=30&w=20&h=15&lu=cm), so sharing a calculation means sharing a URL — your data goes in the link, not through our servers.

Embed the calculator

The box volume calculator can be embedded on any website for free, including commercial sites. The embed builder gives you a copy-and-paste snippet with your preferred size, default unit and starting dimensions.

Sources & references

Found something wrong?

If a result looks off, a carrier divisor is out of date, or a feature behaves strangely — please get in touch. Calculators are only useful if they're correct.