Calculate how much to save each month to reach a savings goal by a date, or how long a monthly deposit takes to get there, with interest.
업데이트 검증한 예제: 6
Put aside $662.08 a month for 5 years to reach $50,000.00: $5,000.00 you already have, $39,724.61 of new deposits and $5,275.39 of interest.
| 년 | Deposits | 이자 | 잔액 |
|---|---|---|---|
| 1 | $7,944.92 | $351.00 | $13,295.92 |
| 2 | $7,944.92 | $688.98 | $21,929.82 |
| 3 | $7,944.92 | $1,040.74 | $30,915.49 |
| 4 | $7,944.92 | $1,406.83 | $40,267.24 |
| 5 | $7,944.92 | $1,787.84 | $50,000.00 |
The denominator is the value of 60 deposits of 1.
The monthly deposit needed is what closes the gap between the goal and what your current savings will grow to: C = (G − S(1 + i)^n) ÷ (((1 + i)^n − 1) ÷ i), where G is the goal, S the amount already saved, i the monthly rate and n the number of months. In the other mode, the number of months comes from logarithms of the same equation and is rounded up to the month in which the goal is reached.
With the defaults, reaching 50,000 in 5 years from 5,000 already saved at 4% a year takes 662.08 a month. The 60 deposits add up to 39,724.61, and interest supplies the remaining 5,275.39 on top of the 5,000 you started with.
Interest is compounded monthly at a fixed rate, with deposits at the end of each month unless you choose the start under More options. Tax on interest and changes in the rate are not included.
검증 출처: Python decimal: (50000 − 5000·(1+0.04/12)^60) / (((1+i)^60 − 1)/i) = 662.0768…; same as Excel =PMT(4%/12,60,-5000,50000)
검증 출처: Python decimal, annuity-due factor: 659.8772…
검증 출처: 12000 / 12 by definition
검증 출처: Starting balance exceeds the goal, so no deposit is needed
Subtract what your current savings will grow to from the goal, then divide by the annuity factor ((1 + i)^n − 1) ÷ i. To reach 50,000 in 5 years from 5,000 at 4% compounded monthly, you need 662.08 a month; Excel's =PMT(4%/12, 60, -5000, 50000) gives the same. With no interest the same goal takes (50,000 − 5,000) ÷ 60 = 750 a month.
Solve the savings equation for the number of months and round up. Starting from 5,000 and saving 500 a month at 4%, the balance first passes 50,000 in month 77, after 6 years 5 months; raising the deposit to 750 cuts that to 54 months. Excel's NPER function solves the same equation.
More the longer the horizon. Over 5 years, 4% interest cuts the deposit needed for 50,000 from 750 to 662.08 a month, and 5% cuts it to 640.87. Over 10 years at 4%, the deposit falls to 288.94 a month and interest supplies 10,327.63 of the 50,000.
Slightly: a deposit made at the start of the month earns one extra month of interest. For 50,000 in 5 years from 5,000 at 4%, the deposit needed is 659.88 at the start of each month against 662.08 at the end, a difference of 2.20 a month.
정확도는 입력값과 계산 방법의 가정에 따라 달라집니다. 십진 연산은 유효숫자 50자리를 사용하지만, 추정값·수치해석 방법·원본 데이터의 정밀도는 더 낮을 수 있습니다. 표시값을 반올림해도 이러한 한계는 사라지지 않습니다. 독립적인 출처의 풀이와 대조한 계산 예시: 6. 예를 들어 “50,000 in 5 years from 5,000 at 4%”은 Python decimal: (50000 − 5000·(1+0.04/12)^60) / (((1+i)^60 − 1)/i) = 662.0768…; same as Excel =PMT(4%/12,60,-5000,50000)와 대조해 확인합니다.
Microsoft Excel PMT function; Microsoft Excel NPER function.
계획을 위한 참고용입니다. 대출기관, 세무당국과 시장은 자체 반올림 방식, 수수료와 규칙을 적용합니다. 계약 등의 결정을 내리기 전에 해당 기관에 수치를 확인하세요.
이 계산기에는 독립적인 출처에서 답을 얻은 계산 예제가 6개 있습니다. 테스트 모음에서 실행되며 여기에서도 실행할 수 있습니다.
뮤추얼 펀드 월 적립 투자(SIP)의 만기 가치를 추정합니다. 연간 납입액 증액을 선택하거나 목표 달성에 필요한 적립액을 계산할 수 있습니다.
초기 예금과 정기 납입금의 미래 가치를 계산합니다. 일 복리와 연속 복리를 포함한 모든 복리 주기를 지원합니다.
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