I use grids less and less and tend to throw down gridless terrain mats, tiles, and clothes.
When I DO use grids, they are only for helping to help draw the environment to a rough scale with a wet erase marker.
To actually measure movement, however, I use a measuring stick. It is six inches long and is marked with alternating black and blank sections every one inch. I got the idea from DM Scotty and he shows how to make these here:
https://www.youtube.com/watch?v=XTT1ZU5pDBg
These are easy. Go get the stuff at a craft store and use up as much of the wood sticks and paint as you can and you'll have enough for a life time, with plenty to spare for giving out to friends.
Throw a bunch of these down at the table during play and never have to worry about grids again. You can move anywhere you have room to move to. Whether you have room to move can be measured using the sticks.
This is such an easy solution. You never have to worry about whether you have a grid or not. Heck you don't even need a mat. You can just use table space and set up the minis and use legos, cups, anything as terrain features. Of course, I like to use nice felt terrain cloths and various crafted and purchased terrain features, but not having to gridout battlemaps for a game is very freeing.
Now, if you are doing all this in a VTT, don't most of those have a tools to measure distance and area with click and drag?