Interest on Deposits Calculator

How to calculate interest on deposits

Deposits are the safest way to save money. Deposit interest is guaranteed by the Deposit Insurance Institution (DIS). This calculator allows you to compare the returns of regular deposits and savings, automatically deducting tax at the place of payment 15% to show the net interest actually received.

Deposit.

Permanent deposits calculate interest on deposited principal. Interest paid at maturity. Formula: Interest = principal × interest rate × (number of months ÷ 12) Net interest = interest × (1 − 0.15)

Savings Deposit (Initial)

Savings deposits are calculated on a monthly basis, the interest received is added back to the principal, and if deposits are made every month, the total will grow faster from both new deposits and capital interest.

Tax deductions at source of 15%.

Interest on all deposits is tax deductible at the point of payment 15% by the bank except:

• Savings deposits with a total interest not exceeding 20,000 baht/year are exempt.
• Certain types of fixed deposits with special terms.

This calculator calculates the tax 15% in all cases to show the minimum return you will receive

Calculation example

Regular deposit 100,000 baht Interest 2% per year Term 12 Months:

• Interest before tax: 100,000 × 2% × 1 = 2,000 baht
• Tax deduction at source: 2,000 × 15% = 300 baht
• Net interest: 2,000 − 300 = 1,700 baht
• Total on expiration: 101,700 baht

Example 2: Regular deposit 1,000,000 baht

Common situations where savings accumulated in large numbers need to be managed to maximize value:

Regular deposit 1,000,000 baht Interest 2.0% per year Term 12 Months:

• Deposit: 1,000,000 baht
• Interest before tax: 1,000,000 × 2.0% × 1 = 20,000 baht
• Tax deduction at source (15%): 20,000 × 15% = 3,000 baht
• Net interest: 20,000 − 3,000 = 17,000 baht
• Total at the deadline: 1,000,000 + 17,000 = 1,017,000 baht
• Net return rate: 17,000 ÷ 1,000,000 = 1.7% per year.

Tip: If you want to get a higher return, compare the interest rates of different banks. Some banks have special promotions for high deposits or try savings accounts to get double interest if you don't withdraw on time.

The formula used to calculate the interest on deposits.

Example of calculating interest on deposits

Example of 1: Deposit 100,000 baht Rate 1.5% per year Deposit 1 per year

Example 2: Quarterly payroll 100,000 baht Rate 1.5%

Example at 3: Regular deposit 5 year, adjusted rate year at 3

Example of how to calculate interest on deposits.

1. Choose an account type and check the current interest rate from the bank.
2. Enter the amount and duration of the deposit.
3. Select interest rate type: Normal or Multiple
4. Calculate interest before tax, then deduct 15% tax at source.
5. Check fees and limits for pre-expired withdrawals.

References:Bank of Thailand: Announces Regular Deposit Rate [Update 2026]

General errors in calculating interest on deposits

To calculate the interest on deposits:

• I don't know if some banks deduct interest tax.
  Deposit 1,000,000 baht get interest 1% = 10,000 baht but pay tax 15% = 1,500 baht actual income = 8,500 baht Check if the bank deducts tax
• Forget that the interest rate "promo" is limited.
  The bank offers a rate of 2.5% per year only 6 for the first month, then reduced to 0.5%. Please provide clear interest rate details.
• Calculate Simple Interest when Compound Interest should be used
  Deposit 100,000 baht at 2% per year. 2 years Simple = 4,000 but Compound = 4,040 baht. Check when the bank charges interest.
• Forget about the penalty interest if you withdraw before the end of the term.
  Regular deposits 12 monthly rate 3% but must be withdrawn in the month 6 bank charges fine or charge savings interest 0.5% instead
• No APR comparison (rate percent per year) between banks
  Bank A gives 2% annually, Bank B gives 2% monthly, different APRs, ask for APY for direct comparison.