Bank Interest Calculator

The National Neopian Bank is where you can safely store your Neopoints. Keeping Neopoints in your bank account protects them from Random Events, which can steal up to 25% of the Neopoints you're carrying. It also prevents you from accidentally losing Neopoints through various activties, like the wheels or other dailies.

Another benefit to the bank is daily interest. Each day, you can collect interest based on your account type and the amount of Neopoints stores. The more Neopoints you have and the better account type (due to a higher interest rate, up to 12.5%), then the more daily interest you can collect. Collecting interest is a manual process, you have to click the "Collect Interest" button, and it'll automatically deposit interest into your bank account.

Every account type requires a minimum balance to unlock, but you do not need to maintain that minimum requirement after upgrading. For example, to unlock the Ultimate Riches! account, you will need at least 10 million NP. Once unlocked, even if you spent most of that balance, you will still keep the account and its maximum 12.5% interest rate. Ultimate Riches is the highest tier, and no account gives a better interest rate.

Some events give a boon that you can choose. This boon is called "Bank Bribery" and it will add an extra 3% to your existing interest rate. When you win this boon from skirmish battles, this boon only lasts a week. Sometimes they will release boons in other events though, like Charity Corner. These boons can last longer. The Charity Corner boon increased your interest for a whole year.

Below is a table of all account types, with their minimum Neopoints balance to unlock the account, and the interest rates for owning the account.

Bank accounts have a maximum of 2,147,483,647 Neopoints due to technical limitations. If you reach this amount, any extra deposits or interest earned will simply disappear. To avoid losing Neopoints, it's best to collect your interest first, then withdraw around 750,000 NP. This keeps your balance below the limit while still letting you earn interest, and gives you spending money for shopping.

This limit is fairly common in software and games because of how numbers are stored in computers using binary digits. The Neopets National Bank uses a 32-bit signed integer to store your account balance. A 32-bit signed integer uses 1-bit to represent whether the number is positive or negative. The remaining 31-bits represent the number. So, 231-1 = 2,147,483,647, which is the bank account limit.

There are two ways TNT could theoretically increase this limit.

1. Switch to an unsigned integer: Since negative bank balances makes no sense on Neopets, using an unsigned integer would double the limit to just over 4 billion NP.
2. Upgrade to a larger integer: Most computers and devices these days are now 64-bit, which can handle much bigger numbers. With a 64-bit integer, then the new maximum would be 9,223,372,036,854,775,807. However, this would require a lot of significant work to the site's code, database, and server software, that might not be worth TNT's effort for such a minor inconvenience.

The Interest Calculator lets you enter your starting balance, account type, and any additional Neopoint contributions. It then shows how your bank balance and interest will grow over a year, with results displayed in an interactive graph.

Bank Contributions:
You can add custom contributions to see how steady deposits can boost your savings. For example, you might set 5,000 NP per day from shop sales. The calculator also includes common sources of income you can enable:

• Tales of Dacardia: Requires linking the mobile game with NeoPass. You get 5 quests per day, each worth 5,000 NP. Completing all 25 quests in a week, gives a 25,000 NP bonus.
• Trudy's Surprise: On average, you earn around 13,000 NP per day. On the 25th day, you'll receive 100,000 NP bonus.
• Faerie Fragments: On average, you earn around 10,000 NP per day from quests. You can also earn around 50,000 NP per week from bonuses.
• Quest Log: Assuming you don't sell or trade any rewarded items, then on average, you can receive around 15,000 per day from daily quests.