Skip to content
ENExplore Calculators

Lazy Load Savings Calculator

Quantify the initial-load saving from lazy loading below-the-fold assets.

About Lazy Load Savings Calculator

Lazy loading removes off-screen images from the initial load entirely. Because most users never scroll to the bottom, a large share of deferred weight is never downloaded at all. Lazy loading above-the-fold images harms LCP, which is why the loading attribute should be set to eager for the hero image.

Formula

Lazy Load Savings

Initial saving = deferred images × average size; never-loaded weight depends on scroll depth

lazy loading
Deferring off-screen assets until they approach the viewport

Worked example

With the default values below, Lazy Load Savings Calculator returns Initial Load Weight Saved of 4,680.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Total images on the pageminimum 0
32
Images above the foldminimum 0
6
Average image sizeminimum 0 KB
180 KB
Connection speedminimum 0.01 Mbps
12 Mbps
Average scroll depthaccepts 0–100 %
55 %

Results

Initial Load Weight Saved
4,680.0 KB
Initial Load Image Weight
1,080.0 KB
Initial Load Time Saved
3,120 ms
Weight Never Loaded at Average Scroll Depth
2,106.0 KB
Images Deferred
26

Step by step

  1. 1Values used
  2. 2Lazy Load Savings
  3. 3Initial Load Weight Saved= 4,680.0 KB
  4. 4Initial Load Image Weight= 1,080.0 KB
  5. 5Initial Load Time Saved= 3,120 ms
  6. 6Weight Never Loaded at Average Scroll Depth= 2,106.0 KB
  7. 7Images Deferred= 26

Assumptions and limits

  • The result is derived only from the 5 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 1 decimal place, 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

How is Lazy Load Savings calculated?

Initial saving = deferred images × average size; never-loaded weight depends on scroll depth Lazy loading removes off-screen images from the initial load entirely. Because most users never scroll to the bottom, a large share of deferred weight is never downloaded at all.

Why does Lazy Load Savings matter?

Lazy loading above-the-fold images harms LCP, which is why the loading attribute should be set to eager for the hero image.

What values do I need to enter?

This calculator takes 5 inputs: Total images on the page, Images above the fold, Average image size, Connection speed, Average scroll depth. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Related Calculators

Lazy Load Savings Calculator | Calcrivo