Both gold bars and gold coins are typically 999.9 fine investment gold, so the metal itself isn't what separates them. The difference is in how they're priced, minted, and sold on. Bars are generally the more cost-efficient way to hold a given amount of gold, while coins carry government backing, official face values, and in some cases collectible or numismatic value on top of their gold content.
Bars are typically cheaper to produce than coins of the same weight, because coins require more elaborate minting (designs, edge detailing, and in many cases higher security features), and the premium reflects that. If your primary goal is maximizing the amount of gold you own for a given budget, a bar of equivalent weight will usually get you there more efficiently.
Well-known coin series - such as those from major national mints - carry a face value and sovereign backing, which some buyers find reassuring, and their design and mint mark make authenticity easy to verify at a glance. Certain series can also carry collectible value beyond their gold content, though that's a separate and less predictable market than buying for the metal itself.
Both are liquid assets and both can be sold back through GoldPenthouse's Sell to Us programme at a live, spot-based quote. In practice, well-known coin series and bars from recognized, reputable mints tend to resell most easily, since buyers don't need to independently verify an unfamiliar producer. This is one reason GoldPenthouse only stocks bars and coins from established, widely recognized mints.
If cost-efficiency is your main priority, bars are usually the better choice gram for gram. If you value the recognizability, legal tender status, or gifting appeal of coins - or you're interested in specific collectible series - coins can be worth the extra premium. Many investors hold a mix of both: bars to build the bulk of a position efficiently, and coins for smaller purchases or gifts.
New to buying physical gold? Start with our Gold Investment Guide. If you're deciding what size bar to start with, see 1g vs 1oz gold bar.