This installment calculator is for shops in Saudi Arabia that sell goods on installments. Enter the cash price, the down payment, the number of installments and the markup you agreed with the customer, and you get the installment amount and a payment schedule with a due date for each one. You choose how the markup is charged: a flat rate on the whole amount, or a declining rate on the balance still owed. Then download the schedule as an Excel file with working formulas, or as a PDF to hand to the customer.
This page is a calculator only. It does not offer, arrange or broker financing. The rate, the number of instalments and their terms are an agreement between you and your customer.
How to calculate an installment
Start from the amount financed: the cash selling price minus the down payment. That, not the full price, is what the markup is charged on. Then choose how the markup is worked out.
Financed = Price − Down · Flat: Profit = Financed × Rate × Years · Installment = (Financed + Profit) ÷ n
Flat rate vs declining balance
With a flat rate, the markup is charged once on the whole amount financed for the full term, and then split evenly across the installments together with the amount. It is the common method for appliances and furniture sold on installments because it is easy to explain to a customer. On a declining balance, the markup is charged each month only on the balance still owed, so it shrinks with every payment while the installment itself stays the same, because the share that repays the amount grows.
That is why two offers cannot be compared on the rate alone. A 10% flat rate is roughly 17.97% a year on a declining balance in the first example, and the calculator shows this figure under the result when you use the flat method.
| SAR 10,000 financed over 12 months at 10% | Installment | Total markup |
|---|---|---|
| Flat rate | 916.67 | 1,000.00 |
| Declining balance | 879.16 | 549.89 |
A payment schedule with due dates
The schedule starts on the first installment date you pick and adds a month for each installment, or three months if you choose quarterly installments in the advanced options. If the first installment falls on the 31st, the installment in a shorter month falls on its last day. Each row shows how much of the payment goes to the amount and how much to the markup, and the balance after it, so you know what the customer still owes in any month. In the advanced options you can also add Hijri dates from the Umm al-Qura calendar used in Saudi Arabia, which some customers expect on a contract; they may differ by a day from the sighted moon.
The Excel file carries the same formulas: one cell for the amount, one for the rate and one for the number of installments, with the installment calculated from them. Change the rate in the file and the whole schedule updates, while the dates stay as entered.
Common installment calculation mistakes
- Charging the markup on the full price before taking off the down payment.
- Multiplying the annual rate by the number of installments as if it were monthly: 10% over 12 months is a 10% markup, not 120%.
- Comparing a flat rate with a declining-balance rate as if they were the same number.
- Rounding every installment up without adjusting the last one, so the customer pays more halalas than agreed.
- Leaving due dates out of the contract, which makes it hard to say which installment is late.
What to do after you get the result
Print the payment schedule as a PDF and attach it to the sales contract, so the customer sees each installment amount, its date and the balance after it. Download the Excel version to track the installments you collect. The calculation does not replace a written contract: late payment, early settlement and who owns the goods until they are paid for are set by the contract between you and the customer and by the regulations in force in the Kingdom.
When installments become part of your daily sales
A single schedule takes a minute. A shop selling on installments to dozens of customers needs to know every day which installments are due, who is late and how much each customer still owes, and to see sales and collections in its accounts. At Microtec we offer O-Green to retailers across Saudi Arabia, a cashier and point-of-sale system for shops. Try it on your own store's sales before you decide.