Questions tagged [compound-interest]
26 questions
5
votes
3 answers
Estimating Exponents
What's the best way to estimate exponents by hand? Say for example $(1.07)^{10}$ $\sim2$, or like $(1.07)^{15}$, or $(1.05)^{15}$. Is there any standard way of doing these calculations?
John Li
- 101
2
votes
0 answers
How to calculate the total APY of two compounding periods at different rates?
I'm trying to figure out the total APY of \$6,600 continuously compounded at 12.93% APY, and 4.1% APY in loyalty rewards. Every five days I cash in my rewards for \$5.50, and compound that. I'm also interested in the total rate if rewards were…
ZeroPhase
- 229
1
vote
2 answers
I'm playing around with the compound interest formula and I'm not getting the answers I expect. Wondered why??
Below is what I was reading:
If you deposit $£1,000$ in a bank account which is paying $3\%$ compound interest per year. How much interest would be earnt over $3$ years?
The formula used to solve this was:
$$1000 \times 1.03^3 = £1,092.73$$
Then you…
troy beckett
- 126
1
vote
0 answers
Compounding Interest formula adding increasing annual contributions
thank you for your time. I have a question about generating a formula similar to this question.
My question is, what would the formula look like if I wanted to contribute $10\%$ of my base salary of $\$90,000$ into an annuity that grows $2\%$…
0
votes
1 answer
Compound interest in between the compounding period
Background: I'm an engineering student with no experience with a real investment account or anything of that sort.
If we were to extend the concept of compound interest strictly mathematically, the formula would be:
$$\text{Amount} =…
0
votes
1 answer
Intuition for continuous compound interest
The formula for continuos compound interest is
$$A = Pe^{(rt)}$$
Where $r$ is the interest rate per year.
Interestingly, even though the money is compounded continuosly , it still depends on the annual interest rate rather than instantaneous…
Vinay5101
- 19
0
votes
0 answers
The different compound interst formulas
I am very confused about compound interest rates , i know for the most basic example if we are given a yearly rate of say 10% , to calculate the nominal value of whatever your deposit would be ,it would be PV*(1+r/100)^t , t being the number of…
j jose
- 59
0
votes
1 answer
Finding the interest rate of a loan with expected balance after certain period
I have created a table of repayment schedule of a loan amount \$20,000 at 12% annual interest rate and a repayment of \$500 each month using Excel. The balance, using the first month as an example, is calculated as:
($20,000 -…
user1589188
- 111
0
votes
0 answers
Reversing the compound interest formula
The compound interest formula is
$$
A =P( 1+r ) ^{n}
$$
If I want to find $n$ it seems logical to that I just solve for it using the logarithm base (1+r), like so:
First divide by $P$:
$$
\dfrac{A}{P} = ( 1+r) ^{n}
$$
and…
jk47
- 1
0
votes
1 answer
Annuity-Due with Varying Payments (Arithmetics)
I need help to derivate a formula for the present value of an annuity with varying payments with the first payment being P at time = 0, and add a constant Q every increment of time.
$$P + (P+Q)v + (P+2Q)v^2+(P+3Q)v^3+ \dots + (P+(n-1)Q)v^{n-1}$$
A…
HIken
- 11