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Page Weight Calculator

Page load time from file transfer alone follows the formula Load Time = (File Size in KB x 8) / (Speed in Mbps x 1000), converting kilobytes to kilobits and megabits per second to kilobits per second. A 500KB page on a 4G connection (20 Mbps) takes approximately (500 x 8) / (20 x 1000) = 0.2 seconds for the raw transfer. Enter a page size below to see estimated load times across 3G, 4G, broadband, and fiber connections.

Quick Answer

A 500KB web page takes approximately 2.5 seconds to transfer on 3G (1.6 Mbps), 0.2 seconds on 4G (20 Mbps), 0.08 seconds on broadband (50 Mbps), and 0.04 seconds on fiber (100 Mbps).

Page Size

Common Examples

Input Result
500 KB on 3G (1.6 Mbps) Approximately 2.5 seconds
500 KB on 4G (20 Mbps) Approximately 0.2 seconds
2 MB on 3G (1.6 Mbps) Approximately 10.24 seconds
100 KB on broadband (50 Mbps) Approximately 16ms
5 MB on fiber (100 Mbps) Approximately 0.41 seconds

How It Works

The raw transfer time for a file depends on its size and the connection speed. The conversion requires matching units:

Load Time (seconds) = (File Size in kilobits) / (Speed in kilobits per second)

Since file sizes are measured in bytes and connection speeds in bits:

  • 1 KB = 8 kilobits (Kb)
  • 1 Mbps = 1,000 kbps

So: Load Time = (Size KB x 8) / (Speed Mbps x 1,000)

Connection speeds used

  • 3G: 1.6 Mbps (typical real-world 3G download speed)
  • 4G / LTE: 20 Mbps (typical real-world LTE speed)
  • Broadband: 50 Mbps (average home broadband)
  • Fiber: 100 Mbps (fiber-optic connection)

What the numbers do not include

This calculation estimates raw transfer time only. Actual page load time also depends on DNS resolution, TCP connection setup, TLS negotiation, server response time (TTFB), number of HTTP requests, render-blocking resources, JavaScript execution, and browser rendering. Real-world load times are typically 2-5x longer than raw transfer time.

Web performance budgets

Common page weight recommendations:

  • Under 500 KB: Fast on all connections
  • 500 KB to 1 MB: Acceptable for most sites
  • 1 MB to 3 MB: Consider optimizing images and scripts
  • Over 3 MB: Likely to cause poor experience on slower connections

The median web page size as of 2025 is approximately 2.3 MB, though performance-focused sites aim for well under 1 MB.

Worked Example

For a 750 KB page on a 4G connection (20 Mbps): Kilobits = 750 x 8 = 6,000 Kb. Connection speed = 20 x 1,000 = 20,000 kbps. Load time = 6,000 / 20,000 = 0.3 seconds. On 3G (1.6 Mbps): 6,000 / 1,600 = 3.75 seconds.

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Frequently Asked Questions

What is a good page weight for a website?
For optimal performance, aim for a total page weight under 500 KB. Most performance-focused sites keep their initial page load under 1 MB. The total includes HTML, CSS, JavaScript, images, fonts, and any other assets. Images typically account for the largest share of page weight.
Why is my actual load time longer than the calculated time?
This calculator estimates raw transfer time only. Real-world load time includes additional factors: DNS lookup (50-200ms), TCP and TLS handshake (100-300ms), server processing time, multiple sequential HTTP requests, render-blocking JavaScript, and browser layout and paint operations. These can add 1-5 seconds depending on the site architecture.
How can I reduce my page weight?
The most impactful optimizations include compressing images (use WebP or AVIF format), minifying CSS and JavaScript, enabling gzip or Brotli compression on the server, lazy loading images below the fold, removing unused CSS and JavaScript, and using system fonts or limiting web font weights.
Does this account for compression?
No. Enter the actual transfer size (after server-side compression) for accurate results. Most web servers use gzip or Brotli compression, which can reduce text-based assets (HTML, CSS, JS) by 60-80%. You can find the actual transfer size in the browser DevTools Network tab.
What is the difference between page weight and transfer size?
Page weight (or page size) is the uncompressed total of all resources. Transfer size is the amount of data actually sent over the network, which is smaller due to gzip/Brotli compression. For accurate load time estimates, use the transfer size. Browser DevTools show both values in the Network tab.