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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.

Atualizado Exemplos verificados: 5

$
%
Experimentar
Juros
$
Juros: $1,800.00
Casas decimais: 2; Ao mais próximo; empates para o dígito par
Total amount
$11,800.00
Interest per year
$600.00
Amount if compounded yearly
$11,910.16

At 6% simple interest, $10,000.00 earns $600.00 a year, so $1,800.00 over the term. Compounding yearly at the same rate would give $110.16 more.

Amount at maturity

$11.8Kat maturity
Principal84.7%Juros15.3%

Balance over time

$10K$10.5K$11K$11.5K0123Years
Simple interestCompounded yearly
Interest by year Linhas: 3
PeriodInterest in periodInterest so farSaldo
Year 1$600.00$600.00$10,600.00
Year 2$600.00$1,200.00$11,200.00
Year 3$600.00$1,800.00$11,800.00
Como é calculado S

  1. Time in years

    t=3=3t = 3 = 3

  2. Juros

    I=Prt=10,000.00×0.06×3=1,800.00I = P r t = 10{,}000.00 \times 0.06 \times 3 = 1{,}800.00

  3. Total amount

    A=P+I=10,000.00+1,800.00=11,800.00A = P + I = 10{,}000.00 + 1{,}800.00 = 11{,}800.00

    Rounded half-to-even to 2 decimals for display only.

Sobre Simple interest calculator

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.

Exemplos resolvidos

10,000 at 6% for 3 years

Principal
10,000
Interest rate (per year)
6%
Tempo
3
Time in
Anos
Juros
1,800.00
Total amount
11,800.00
Amount if compounded yearly
11,910.16

Fonte de verificação: 10000 × 0.06 × 3 by hand; 10000 × 1.06³ = 11910.16 (Python decimal)

5,000 at 8% for 9 months

Principal
5000
Interest rate (per year)
8%
Tempo
9
Time in
Meses
Juros
300.00
Total amount
5,300.00

Fonte de verificação: 5000 × 0.08 × 9/12 by hand

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

Principal
20,000
Interest rate (per year)
7.5%
Tempo
90
Time in
Days
Days in a year
365 (actual/365)
Juros
369.86

Fonte de verificação: 20000 × 0.075 × 90/365 = 369.8630… (Python decimal)

Same loan on a 360-day year

Principal
20,000
Interest rate (per year)
7.5%
Tempo
90
Time in
Days
Days in a year
360 (banker's year)
Juros
375.00

Fonte de verificação: 20000 × 0.075 × 90/360 by hand

Perguntas

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.

Qual é a precisão de “Simple interest calculator”?

A precisão depende dos dados inseridos e das hipóteses do método. O cálculo decimal usa 50 algarismos significativos, mas estimativas, métodos numéricos e dados de origem podem ter menor precisão; o arredondamento exibido não elimina essas limitações. Exemplos resolvidos verificados com fontes independentes: 5. Por exemplo, “10,000 at 6% for 3 years” é verificado com 10000 × 0.06 × 3 by hand; 10000 × 1.06³ = 11910.16 (Python decimal).

De onde vem o método?

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).

Sobre esta calculadora

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

Fontes

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

Apenas para planejamento. Credores, autoridades fiscais e mercados aplicam seus próprios arredondamentos, tarifas e regras; confirme os valores com eles antes de assumir um compromisso.

Verificado com as referências

Esta calculadora inclui 5 exemplos resolvidos com respostas de fontes independentes. Eles fazem parte do conjunto de testes e você também pode executá-los aqui.

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