The Personal Loan Installments Calculator estimates a loan and interest estimate for your scenario from the quantities, rates, period, units and other assumptions requested on the page. Replace the example values with your own personal loan installments figures and recalculate after changing an assumption. Use it to compare scenarios, then verify any current rate or fee before acting.
Calculate monthly payments, total interest and effective interest rate (EIR) for flat rate personal loans
Calculation results
A month's worth.
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Total Interest
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Total payments
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Effective Interest Rate (EIR)
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Loan.-
Flat Rate per year-
Number of instalments-
How to calculate a flat rate personal loan
Personal loans in Thailand are mostly flat rate interest, which means interest is calculated on the principal for the duration of the loan, not on the remaining amount of debt, making the total interest higher than the flat rate interest.
Flat Rate Calculator
Payments = (principal + principal × Flat Rate% × year period) ÷ number of payments
Effective Interest Rate (EIR)
EIR is an interest rate that reduces principal and interest that gives the same installments. Calculated by method Newton-Raphson To find the monthly interest rate r that makes the sum of the present value of all installments equal to the principal, generally EIR ≈ Flat Rate × 1.8
Total interest = 30,000 baht | Total payments = 130,000 baht
EIR ≈ 18-19% per year
Credit comparison tips.
Use EIR to compare inter-institutional loans, not flat rate.
Check the management fees and insurance.
The massage should not exceed 30% of net income.
Early repayment with reduced interest rate (depending on contract terms)
Frequently asked questions
What is a flat rate? How is it different from a reduction in principal?
Flat rate is calculating interest from the full principal for the duration of the contract, making the total interest higher. The discount on the principal reduces interest from the remaining debt. When you continue to pay, interest rates decrease.
What is the effective interest rate (EIR)?
EIR (Effective Interest Rate) or effective interest rate It is an interest rate that reduces principal and interest for the same installment. Generally, EIR ≈ Flat Rate × 1.8, for example, a flat rate of 10% per year has an EIR of approximately 18% per year. The Bank of Thailand requires that EIR must be notified to customers.
What's the maximum interest rate on a flat-rate personal loan?
The Bank of Thailand has set the EIR ceiling for personal loans to not exceed 25% per year, which is a flat rate of about 13-14% per year. Debit cards usually charge EIR 25%. Commercial bank loans usually charge EIR 18-22%.
What's the maximum amount you can borrow on a personal loan?
The amount of a personal loan is typically 5 times the monthly income, such as income 30,000 baht/month maximum loan amount approximately 150,000 baht maximum repayment period 60 months (5 years) for a general personal loan
Installments and interest are numbers for preliminary screening of plans. Before actually applying, you should compare rates, fees, and conditions from service providers.
Calculated based on the principal, rate and term you enter.
This does not include certain types of fees, insurance or specific promotional conditions.
The total installment should not put pressure on monthly cash flow.
Disclaimer: The results of the calculation are only estimates. The actual interest rate (EIR) may differ slightly from the way the financial institution calculates it. It is not financial advice. Please check the terms directly with the financial institution.
English calculator guide
How to use the Personal Loan Installments Calculator
Use this page to test a specific personal loan installments scenario. Enter your own values in the calculator above, review the units beside each field, and recalculate after changing an assumption. The result updates the personal loan installments estimate instead of relying on a generic example.
Build a baseline personal loan installments case with figures that match your situation.
Run a second personal loan installments case after changing the rate, period, quantity or other key assumption.
Record the difference between the two personal loan installments results and the input responsible for it.
Inputs for the personal loan installments estimate
For this personal loan installments calculation, check the quantities, rates, period, units and other assumptions requested on the page. The result is designed to show a loan and interest estimate for your scenario, not a guaranteed provider price or official decision.
How the personal loan installments result is calculated
The calculator models principal, interest, repayment timing and term using the assumptions shown on the page. Reusing the same personal loan installments inputs will produce the same estimate, which makes the page suitable for controlled scenario comparisons.
Checks for a personal loan installments decision
Confirm any current rate, threshold or provider rule that could change the final amount. For personal loan installments, Use the result to compare affordability, not as a lending offer. Check the lender’s effective rate, fees, insurance, payment schedule and approval conditions before committing. Check the important inputs and any current provider or authority rules before using the result for a decision.
Language QA
Terminology, numeric values and calculator controls checked
Review formula structure, test cases, data sources, effective dates, and risk language accordingly.How to check our · There is no claim that an outside professional reviewed it. Unless the page directly states the name and qualifications. This content is therefore not individual advice.
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