Yes, and some ring retailers recommend it. But it isn’t a good idea because string can stretch and twist. You need something a lot more solid for an accurate reading. If you’re spending money on a gorgeous diamond ring, it’s worth making the effort to get the size right.

Temperature is important because you actually shrink and grow depending on how cold or warm it is. Cold fingers are smaller than hot fingers, so if you measure your finger when you’re too hot or cold your reading won’t be accurate. Wait until your body temperature is just right, neither too hot nor too cold. It’s also best to measure at the end of the day because fingers tend to be smaller early in the morning.

What if you’ve identified two ring sizes, both of which seem to fit just fine? It’s best to go with the bigger size. Plus, as a general rule, the wider the band the larger the size. If you’d like a wide wedding band, move up a size and you’ll find it much more comfortable. Choose your regular size and your ring might feel a bit tight, simply because it’s wider than average.

Some of us have bigger, more prominent knuckles than others, and men tend to have bigger knuckles than women. It helps to measure the base of your finger (at the palm end) and the knuckle separately, then pick a suitable size somewhere in between the two.