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Webpage Weight

Free Webpage Weight calculator with clear step-by-step results.

About Webpage Weight

Separates text assets, which compress by roughly 70% over the wire, from images and fonts which are already compressed and do not benefit. The distinction matters because the transferred figure drives load time while the uncompressed figure drives parse and execution cost.

Formulas

Transferred weight

KB = (HTML + CSS + JS) x (1 - compression) + images + fonts

Transfer time

Seconds = transferred KB x 8 / (Mbps x 1000)

Worked example

With the default values below, Webpage Weight returns Bytes actually transferred of 1,177.5. Change any input above and every figure here is recalculated in your browser.

Inputs used

HTMLminimum 0 KB
35 KB
CSSminimum 0 KB
70 KB
JavaScriptminimum 0 KB
420 KB
Imagesminimum 0 KB
900 KB
Fontsminimum 0 KB
120 KB
Connection speedminimum 0.1 Mbps
8 Mbps
Saving from text compressionaccepts 0–90 %
70 %

Results

Bytes actually transferred
1,177.5 KB
Uncompressed page weight
1,545.0 KB
Transfer time at this connection
1.178 s
JavaScript as a share of the page
27.2% %

Step by step

  1. 1Values used
  2. 2Transferred weight
  3. 3Transfer time
  4. 4Bytes actually transferred= 1,177.5 KB
  5. 5Uncompressed page weight= 1,545.0 KB
  6. 6Transfer time at this connection= 1.178 s
  7. 7JavaScript as a share of the page= 27.2 %

Assumptions and limits

  • The result is derived only from the 7 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does uncompressed JavaScript size matter separately?

Because the browser must decompress, parse and compile all of it. A 420 KB bundle compressing to 120 KB still costs the full parse and execution time, which on a mid-range phone can exceed the download time.

What is a reasonable page weight?

Under about 1 MB transferred for a content page, and under 200 KB of JavaScript. Median real-world pages are considerably heavier than that.

Related Calculators

Webpage Weight – Calculate Bytes actually transferred