I'm trying to calculate a lifetime value of a customer. Let's assume a new customer pays $100K per year and stays for 5 years. Let's discount any future years' payments with 10% rate.
This is manual calculation:
Year 1 $100,000.00
Year 2 $90,000.00
Year 3 $81,000.00
Year 4 $72,900.00
Year 5 $65,610.00
---------------------
Total $409,510.00
I can get the same value by using FV with negative rate.
FV(-0.1,5,-100000,0,0) = $409,510.00
What I'm trying to do is to get the same value using PV. And it's not exactly the same:
PV(0.1,5,-100000,0,1) = $416,986.54
I'm not sure what am I missing here. Does MS Office Excel 2010 PV understand discounting differently?
If you calculate out what PV is doing manually, the formula is actually this, for each individual year:
=Base Amount / (1 + Discount Rate) ^ Periods
Vs what FV is doing manually, the formula is this (which you seem to know based on coming to the same answer in your data):
=Base Amount * (1 - Discount Rate) ^ Periods
The reason for the difference in calculation is the mathematical difference between the two items - for background see here: http://www.investopedia.com/walkthrough/corporate-finance/3/time-value-money/future-value.aspx and here: http://www.investopedia.com/walkthrough/corporate-finance/3/time-value-money/present-value-discounting.aspx.
In short, if you have $100k today, and invest it in something which gives you 10% each year, then each year you add 10% of the current balance to get the new balance. ie: in year 1 you add 100k * 10% = 10k, giving a new total of 110k; in year 2 you add 110k * 10% = 11k, giving a new total of 121k, etc. - Mathematically, each year's amount is given by the formula listed above for the FV calculation.
Where this gets tricky is that you are giving yourself a negative interest rate - meaning every year, the value is decreasing each year by 10%. You have attempted to use the FV calculation with a negative interest rate, but that's not quite correct. What you should be using is the PV formula.
For the PV formula, if you know that you will receive 100k each year, you need to determine how much cash you would have needed originally, in order to earn the same amount - that is the present value of the cash flow stream. Now, you need to 'gross-up' the value of each year's income stream. The formula for this gross-up is derived mathematically and results in what I have above there for PV. Think about it like this - if there's a shirt that normally costs $100 and is now 30% off, you can see that you simply multiply it by 30%, to get $70. But if you see of shirt on sale for $70, and it's 30% off, then to determine the original base price you need to take $70 & divide by .3 - which gives us $100.
To prove to yourself that the PV formula is appropriate, take the income stream of, say, year 4 [3 periods of interest later, assuming first payment is received in day 0]: 100k / (1 + 10%)^3 = $75,131. Now, work backwards - if you want to know the future value of a $75k investment held for 3 periods of interest compounded annually with a 10% annual rate, you go: 75,131 * (1 + 10%) ^ 3 = 100k.
This is an important financial distinction, and you should read over the sources I've linked to ensure you understand it.
There is a difference in the calculation. FV takes 100,000 and discounts it by 10% to the number X so that X is 90% of the original value (i.e. X=90,000). PV by contrast discounts it to the number X such that 100,000 is 10% more than X. Quick math says X will be 10/11 of 100,000, i.e. 90909.09.
Indeed, if we apply this calculation 5 times:
Year 1 $100,000.00
Year 2 $90,909.09
Year 3 $82,644.63
Year 4 $75,131.48
Year 5 $68,301.35
---------------------
Total $416,986.5
I don't know if there is a way to make them behave the same way (I don't think there is, as they're calculating different things), but since FV solves your problem why not just use that?
Related
So I am trying to build an excel model where every month the numbers will increase exponentially to a point at the end of the year which is driven by annual expectations. Currently I have it divided by 12 and each year there are huge jumps over the previous making the chart/growth very jumpy. For illustration purposes, lets say for 2020 the desired number for the year is 12. In the current state, I would get 1 per month (12/12), however, what I want is for it to be growing gradually/exponentially, so for example 0.2, 0.5, 0.9 etc with December being the largest, and the sum for the entire year equaling 12. Then the next year (2021), starting in January, it would take into account the December 2020 number and grow from there again to the desired number (lets say total 24 for 2021) and so on. I'd love for it to have a more exponential / hockey stick-like growth.
What would be a good way to do this?
The function RRI can be used to find an interest rate which will give you a given target value. This can be used to find terms in a geometric series which have a given sum (which is what you seem to be asking for).
For example, say you want 12 exponentially increasing numbers which, when added to 100, gets you to 2000. Starting with 100, repeatedly multiply by (1 + RRI(12,100,2000)). To get the numbers that you want (which will be 12 numbers which sum to 1900) just calculate the difference each month:
I think the simplest way to solve this is by using Goal Seek. First you need to build a sheet like this:
You choose the starting value in January (B1) and every month is a constant growth rate (D1) bigger than the previous month. You also calculate the total sum at the bottom in B13.
Now you use goal seek to find the growth rate which makes the sum equal to 12:
The answer I get for a starting value of 0.1 is a growth rate of 1.376:
A business works on a subscription model basis with a expected churn rate (Cancellations) each month during year 1 at 5% & during the following year a churn rate of 2.5% due to the fact these are now established customers (long term).
A new feature or service is launched with a expect increase of subscriptions each month. I need to calculate how many subscriptions would that be in N years based on a 5% churn rate for the first 12 month & a 2.5% churn rate during year 2.
Below is currently how were are calculating this in excel however this is really in inelegant solution when trying to calculate this for say 5 - 10 year impacts.
https://i.stack.imgur.com/yF5Rx.png
Are there any accounting formulas or something mathamitcally I can produce to calculate this in a single cell? Given I would need to set the given churn rates for each year & length of time.
For ease lets say 95% of the time I would be working on a 3 year model of subscriptions & each year will need its own churn rate.
I thought perhaps something with exp & halving the value might work but have not found anything yet.
Here's one way to build the model. I'll make reference to this image:
First we set up the churn model.
Row 1: Since Churn Rates depend on subscription age, Row 1 has the subscription age (in months). This is for reference only and is not used in the calculations.
Row 2: Churn Rates.
Row 3: Since Churn Rates always enter the calculation as (1-ChurnRate), call that term (Single-month) Retention Rate. As an example, in B3 the formula is =1-B2.
Row 4: Since the effects of churn are cumulative over multiple months, we define another term Multi-month Retention Rate (abbreviated MMRR). In the first month this is set to 1; in subsequent months this is the product of previous single-month retention rates. So in C4 the formula is =B4*B3; in C5, =C4*C3, etc.
Row 5: The model as described in the Question indicated a fixed rate of new subscriptions = 100/month. When the subscription rate is fixed, it is convenient to sum up the MMRRs. So in B5 we have =B4; in C5, =B5+C4; in D5, C5+D4; etc.
At this point we're essentially done. If you multiply the values in Row 5 by any fixed rate of new subscriptions (e.g. 100/month in the original Question) we get the number of subscribers in that month. But what if you want to model where the number of new subscriptions varies month to month? Here's how ...
The basic idea is to multiply the monthly subscription rate by its age-appropriate MMRR. Note that Row 8 has varying numbers of new subscriptions (100, 110, 97) in the first 3 months. To get the total subscriptions in Mar-19 for example, we need to
multiply the 100 (Jan-19) subscriptions (that have a 2 month age) by the MMRR for a 2-month old subscription (0.9025),
multiply the 110 (Feb-19) subscriptions (that have a 1 month age) by the MMRR for a 1-month old subscription (0.95),
multiply the 97 (Mar-19) subscriptions (that have a 0 month age) by the MMRR for a 0-month old subscription (1), and
add those three products together.
This could be calculated on the worksheet by entering in D9 the formula =B8*D4+C8*C4+D8*B4. This type of calculation (sum up the pair-wise products of two arrays) is often done with Excel's SUMPRODUCT function. Here we need to take one of the arrays in reverse order, which is not directly supported by Excel. You could enter new subscriptions in reverse order, but that's an ugly kludge. Fortunately, it is do-able with a combination of the OFFSET(), COLUMN() and N() worksheet functions (see here for details). The required formula for B9 is
=SUMPRODUCT($B4:B4,N(OFFSET(B8,0,-(COLUMN($B8:B8)-COLUMN($B8)),1,1)))
This can then be copy/pasted into the rest of row 9.
This model approach is pretty flexible: the churn rates (row 2) and subscription rates (row 8) can both be varied month to month; the total number of retained monthly subscriptions is calculated automatically.
I am trying to create a formula in Excel that solves for the base number of units needed on a monthly interval with an annual growth escalator that matches in whole units the total I'm starting with. I can't from a practical standpoint have fractions.
This is an example of the formula x is number of monthly units, y is the total number of units and the desired annual growth rate is 20%. Here is the algebra butin practice only one variable will need to be solved for (x): y= 12x + (1.2x)*12+(1.2^2)*x*12+(1.2^3)*x*12. I get close using the round function but always end up a few short of the total desired due. Is there a way to add on the difference at the end formulaically?
ROUND(20000/(12+(12*(1+20%))+12*(1+20%)^2+12*(1+20%)^3),0)
I'm extremely close but I need to make sure the total by month matches the total desired.
So for example: You want to receive $X in today's dollars at the beginning of each year for Z# of years. Assuming a 3% constant inflation rate and a 7% compounded annual rate of return.
I know the formula to calculate the inflation adjusted returns; for the rate of return you have to use this formula:
[[(1+investment return)/(1+inflation rate)]-1]*100 OR in this instance
[(1.07/1.03)-1]*100
then you need to use the Present Value formula to calculate the rest PV(rate,nper,pmt,[fv],[type]) to find out how much $ is needed to sustain $X adjusted for inflation for Z# years. So here's my formula that I'm using:
=PV((((((1+E16)/(1+B15))-1)*100)),H14,-O7,,1)
Where E16 is my Annual Return (7%), B15 is my Inflation Rate (3), H14 is the number of years I need the payment (30), -O7 is my payment amount (made negative to give a positive #)($127,621.98), future value [fv] is left blank as is unnecessary, and Type is 1 so I calculate for receiving the payment at the beginning of the year.
What all this "should" return is $2,325,327.2044 according to my financial calculator, however Excel is giving me $160,484.6347.
What am I doing wrong here?
The syntax for PV includes:
Rate Required. The interest rate per period. For example, if you obtain an automobile loan at a 10 percent annual interest rate and make monthly payments, your interest rate per month is 10%/12, or 0.83%. You would enter 10%/12, or 0.83%, or 0.0083, into the formula as the rate.
So don't factor by *100.
Many parentheses serve no purpose as the formula below is sufficient:
=PV((1+E16)/(1+B15)-1,H14,-O7,,1)
The Excel (2013) result to four DP is: $2,325,327.2045.
I'm trying to figure out what rate of return I would need on an investment in order to compare to paying down a mortgage.
I have calculated the change in the mortgage - I know how much money I'd save by the end of the loan term and how much money I'd need to put in. I'm trying to compare that to an equivalent investment - treat any lump sum payment as the principal of an investment, treat any monthly overpayment as a monthly contribution to an investment, plug in the final value, and solve for the effective rate of return.
I've looked at the RATE and the IRR commands. IRR seems close to what I want, but it wants a series of values for the input flows, but I have it as a periodic regular investment.
For an example with numbers - if I pay an extra $100 a month on the mortgage for 120 months, I can save $10000 in total cost. What command can I use to calculate this in terms of an investment? If I invest $100 a month for ten years and end up with $10000, what was my annualized rate of return?
If I start with principal PV invested at rate R, I contribute monthly payment M for N months, and I end up with final value FV at the end of those N months, I'd like to solve for R given the other variables.
I know there's another factor regarding the mortgage interesting being tax deductible - I'll look at worrying about that after I figure this part out.
:)
Your monthly return is given by this RATE formula
number of periods = 120 (10*12)
contributions of $100 per period
future value of 10,0000
=RATE(10*12,-100,0,10000)
=-0.32% per month
Note as a check =RATE(10*12,-100,0,12000) = 0
which is equivalent to an annual rate of
=1-(1-0.32%)^12
=-3.73%