TY for the A2A.

I’m sure people in the industry can figure out from the card # whether it’s a debit card or credit card. But, for the common man, it’s not so easy to differentiate between a credit card and a debit card.

All my debit cards say somewhere on the card itself that they’re DEBIT, although one of them obfuscates it as “diamond debit”.

Of late, my credit cards don’t say CREDIT anywhere on the card - at least not prominently enough for me to pick it up with a quick glance.

I used to keep my credit cards and debit cards in different slots in my wallet, so that I knew which was which and I didn’t use the wrong card for the wrong purpose e.g. credit card for cash withdrawal at ATM OR debit card for instore shopping at POS.

Lately, after the PINless regime has been enforced in India for contactless credit cards and debit cards, I have stopped carrying my debit cards around. All payments cards in my wallet are now credit cards. End of confusion! See also Ketharaman Swaminathan's answer to Why do many countries don't require to enter PIN to verify a credit card transaction? Is the safety comprised?.

PS: I’m not covering the trivial case of differentiating between a credit card and debit card *after* using the card since I’ve assumed that your original question implicitly references the pre-usage situation.