# Simple interest calculator

> Calculate simple interest (I = P × r × t) and the maturity amount on a principal for a term in years, months or days.

النسخة التفاعلية: https://www.calcopenly.com/ar/finance/simple-interest-calculator
الموضوع: الحاسبات المالية

Simple interest is paid only on the original principal: I = P × r × t, where r is the yearly rate as a decimal and t the time in years. A term in months is divided by 12, and a term in days by 365 (actual/365) or by 360, the banker's year some lenders and money markets use. The amount due at maturity is A = P(1 + rt).

With the defaults, 10,000 at 6% for 3 years earns 600 a year and 1,800 in total, for a maturity amount of 11,800. Compounded yearly at the same rate, the same deposit would reach 11,910.16, which is 110.16 more.

Interest here never earns interest of its own. Savings accounts and most deposits compound, so use the compound interest calculator for them; simple interest suits short loans, flat-rate quotes and interest accrued between coupon dates.

## المدخلات

- **أصل القرض**
- **Interest rate (per year)**
- **الوقت**
- **Time in** (الخيارات: سنوات, أشهر, Days)
- **Days in a year** (الخيارات: 365 (actual/365), 360 (banker's year))

## النتائج

- الفائدة — النتيجة الرئيسية
- Total amount
- Interest per year
- Amount if compounded yearly

## الصيغة

$$
I = P \cdot r \cdot t,\qquad A = P(1 + r t)
$$

## أمثلة محلولة

### 10,000 at 6% for 3 years

- أصل القرض: 10,000
- Interest rate (per year): 6%
- الوقت: 3
- Time in: سنوات
- **الفائدة: 1,800.00**
- **Total amount: 11,800.00**
- **Amount if compounded yearly: 11,910.16**
- مصدر التحقق: ⁨10000 × 0.06 × 3 by hand; 10000 × 1.06³ = 11910.16 (Python decimal)⁩

### 5,000 at 8% for 9 months

- أصل القرض: 5000
- Interest rate (per year): 8%
- الوقت: 9
- Time in: أشهر
- **الفائدة: 300.00**
- **Total amount: 5,300.00**
- مصدر التحقق: ⁨5000 × 0.08 × 9/12 by hand⁩

### 20,000 at 7.5% for 90 days, actual/365

- أصل القرض: 20,000
- Interest rate (per year): 7.5%
- الوقت: 90
- Time in: Days
- Days in a year: 365 (actual/365)
- **الفائدة: 369.86**
- مصدر التحقق: ⁨20000 × 0.075 × 90/365 = 369.8630… (Python decimal)⁩

### Same loan on a 360-day year

- أصل القرض: 20,000
- Interest rate (per year): 7.5%
- الوقت: 90
- Time in: Days
- Days in a year: 360 (banker's year)
- **الفائدة: 375.00**
- مصدر التحقق: ⁨20000 × 0.075 × 90/360 by hand⁩

### Zero rate

- أصل القرض: 1000
- Interest rate (per year): 0%
- الوقت: 5
- Time in: سنوات
- **الفائدة: 0.00**
- **Total amount: 1,000.00**
- مصدر التحقق: ⁨Definition: no rate, no interest⁩

## الأسئلة

### How do you calculate simple interest?

Multiply the principal by the yearly rate and by the time in years: I = P × r × t. 10,000 at 6% for 3 years earns 10,000 × 0.06 × 3 = 1,800, so 11,800 is repaid. For a term in months, divide by 12 first: 5,000 at 8% for 9 months earns 5,000 × 0.08 × 9/12 = 300.

### How do you calculate simple interest for a number of days?

Divide the days by the day-count basis before multiplying. 20,000 at 7.5% for 90 days earns 20,000 × 0.075 × 90/365 = 369.86 on an actual/365 basis, and 375.00 on a 360-day banker's year. Excel's ACCRINTM function uses basis 3 for actual/365 and basis 2 for actual/360.

### How do you find the rate or the time from simple interest?

Rearrange I = P × r × t. The rate is r = I ÷ (P × t): earning 1,800 on 10,000 over 3 years means 1,800 ÷ 30,000 = 6% a year. The time is t = I ÷ (P × r): earning 3,000 on 10,000 at 6% takes 3,000 ÷ 600 = 5 years.

### Is simple interest better than compound interest?

For a borrower, yes; for a saver, no. Simple interest grows in a straight line, while compound interest also earns interest on interest. On 10,000 at 6%, the gap is only 110.16 after 3 years (1,800 against 1,910.16), but after 20 years simple interest totals 12,000 while yearly compounding adds 22,071.35.

### ما مدى دقة «⁨Simple interest calculator⁩»؟

تعتمد الدقة على مدخلاتك وافتراضات الطريقة. يستخدم الحساب العشري 50 رقمًا معنويًا، لكن التقديرات والأساليب العددية وبيانات المصدر قد تكون أقل دقة؛ تقريب القيم المعروضة لا يزيل هذه الحدود. أمثلة محلولة جرى التحقق منها بمصادر مستقلة: 5. مثلًا، يجري التحقق من «⁨10,000 at 6% for 3 years⁩» بالرجوع إلى ⁨10000 × 0.06 × 3 by hand; 10000 × 1.06³ = 11910.16 (Python decimal)⁩.

### ما مصدر هذه الطريقة؟

OpenStax Prealgebra 2e — Simple Interest Applications (I = Prt); Brealey, Myers & Allen — Principles of Corporate Finance, ch. 2 (simple vs compound interest); Microsoft Excel ACCRINTM function (simple interest accrued to maturity, basis 2 = actual/360, 3 = actual/365).

## المصادر

- [OpenStax Prealgebra 2e — Simple Interest Applications (I = Prt)](https://openstax.org/books/prealgebra-2e/pages/6-4-solve-simple-interest-applications)
- Brealey, Myers & Allen — Principles of Corporate Finance, ch. 2 (simple vs compound interest)
- [Microsoft Excel ACCRINTM function (simple interest accrued to maturity, basis 2 = actual/360, 3 = actual/365)](https://support.microsoft.com/en-gb/office/accrintm-function-f62f01f9-5754-4cc4-805b-0e70199328a7)

_للتخطيط فقط. يطبق المقرضون والسلطات الضريبية والأسواق قواعدهم الخاصة في التقريب والرسوم؛ تأكد من الأرقام لديهم قبل الالتزام._