What you need:
  • URL address of an image showing the blueprint of the original vehicle (you can find plenty of blueprints e.g. here)
  • known dimension - one dimension of your model that you know (e.g. wheel diameter or track's width)
  • web browser supporting JavaScript, SVG files and alternate style sheets (for printing). Recommended browsers: Chrome, Firefox, Opera. Internet Explorer is not recommended.
  • note: this page will stretch to your screen's width. It works best with resolutions of at least 1600px width.
Step 1
Paste & load URL address of the image file (NOT of a website that includes this image, but of the image itself - it usually ends with .jpg or .png):


Then, you can:
fit image to the width of canvas restore image to the original size
Step 2
Draw the known dimension on the image below (e.g. wheel's diameter), then enter how many studs it is and specify whether it's width or height:
studs       width      height
click here to calculate.
Note: the width or height is always taken from the first measurement, no matter how many you draw and even if you clear them all. It lets you change the dimension above and get updated results without starting anew.
Calculate the scale:
If you know the real counterpart of the dimension you entered above, enter it here to calculate what scale your model is in:
Settings
Units:     Unit accuracy:

Color used:

Clearing:
clear the last measurement
clear all measurements

What next?
You can print the blueprint with the measurements straight from here provided you're using a web browser that supports alternate style sheets (read: not Internet Explorer).
You can also use Print Screen to copy the blueprint for further reference.
Firefox users can use ScreenGrab to save the blueprint.