Reconcile debits & credits using Solver [Advanced Excel]

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Here is a tricky problem often faced by accountants and finance professionals: Let’s say you have 5 customers. Each of them need to pay you some money. Instead of paying the total amount in one go, they paid you in 30 small transactions. The total amount of these transactions matches how much they need to pay you. But you don’t know which customer paid which amounts. How would you reconcile the books?

If you match the transactions manually, it can take an eternity – after all there are more than 931 zillion combinations (5^30).

This is where solver can be handy. Solver can find optimal solution for problems like this before you finish your first cup of coffee.

Reconcile debits & credits using solver model – Tutorial

Step 1. Set up your solver model

In a blank sheet, list credits along a column and debits on the top in few columns, as shown below:

In the blank grid, Solver will fill 0 or 1 indicating whether credit in that row is matched with debit in that column or not.

This area is (C6:G35 in my workbook) is known as variable cell range in Solver model.

There are 2 rules to be followed when matching debits to credits:

  • A credit can be matched with only one debit – ie sum of any row in C6:G35 range can be 1, at most.
  • Total reconciled amount should be less than or equal to total credits – ie sum of any column in C6:G35 should be less than values in C5:G5 (debits).

To facilitate these rules, also known as constraints in solver parlance, let’s use column H & row 36.

  • Write =SUM(C6:G6) in H6 and fill down the formula.
  • Write =SUMPRODUCT($B$6:$B$35,C$6:C$35) in C36 and drag sideways to fill the formula in rest of the columns.

Our solver model should look like this:

reconcile-debits-credits-solver-model-workbook-screenshot

Step 2: Set up optimization cell

To do its work, solver needs an optimization cell. Our goal is to maximize the amount of reconciled amount. So, in a blank cell write =SUM(C6:G36). This will be our optimization cell.

Step 3: Launch solver

Select the optimization cell (in my workbook, this is J6) and go to Data > Solver. (If you do not have solver, enable it using these instructions.)

Set up solver model as:

  1. Objective is to to maximize J6.
  2. Variable cells are C6:G35
  3. Constraints
    • C6:G35 should be binary (o or 1)
    • C36:G36 should be <= C5:G5
    • H6:H35 should be <= 1
  4. Solver method is Simplex LP (our problem is linear)

match-debits-credits-solver-parameters

When you are ready, Click Solve. Solver should take few minutes to find the solution.

Step 4: Examine the result

solver-solution-reconcile-debits-credits

Once solver finds an answer, it will show Solver Results dialog. Click ok (you may also look at the sensitivity report). This loads the solver solution in to variable cell range.

solver-solution-reconcile-debits-and-credits

Analyze the numbers and enjoy.

What if Solver solution is not optimum?

Occasionally, Solver fails to find optimum solution for linear problems with integer constraints. In such cases, try again by adjusting constraints & precision.

Download example workbook

Please click here to download the example workbook. Play with the solver model to learn more.

Other ways to reconcile data

If you deal with reconciliation problems, check out below examples to learn more:

 

How do you reconcile data?

Solver is a powerful way to reconcile data. It does take some time to set up the model and configure solver, but once your model is ready, Solver does all the heavy lifting.

What about you? What methods do you use to reconcile data? Please share your thoughts and tips in the comment section.

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13 Responses to “Convert fractional Excel time to hours & minutes [Quick tip]”

  1. Debraj Roy says:

    Hi Purna..

    Again a great tip.. Its a great way to convert Fractional Time..
    By the way.. Excel has two great and rarely used formula..

    =DOLLARFR(7.8,60) and =DOLLARDE(7.48,60)

    basically US Account person uses those to convert some currency denomination.. and we can use it to convert Year(i.e 3.11 Year = 3 year 11 month) and Week(6.5 week = 6 week 5 days), in the same manner...

  2. Jason says:

    This doesn't work for me. When applying the custom format of [h]:mm to 7.8 I get 187:12

    Any ideas why?

    • Hui... says:

      @Jason
      7.8 in Excel talk means 7.8 days
      =7.8*24
      =187.2 Hrs
      =187 Hrs 12 Mins

      If you follow Chandoo's instructions you will see that he divides the 7.8 by 24 to get it to a fraction of a day

      Simple, assuming the fractional time is in cell A1,

      Use below steps to convert it to hours & minutes:

      1. In the target cell, write =A1/24
      2. Select the target cell and press CTRL+1 to format it (you can also right click and select format cells)
      3. Select Custom from “Number” tab and enter the code [h]:mm
      4. Done!

  3. WhoKnows says:

    Hi, sorry to point this out but Column C Header is misspelt 'Hours Palyed'

  4. abhishek malik says:

    good one

  5. Julia says:

    So how do I go the other way and get hours and minutes to fractional time?

    • Chandoo says:

      If you have 7.5 in cell A1,

      - Use int(A1) to get the hours.
      - Use mod(A1,1)*60 to get minutes.

      If you have 7:30 (formatted as time) in A1

      - Use hours(a1) to get hours
      - Use minutes(a1) to get minutes.

      • Paula says:

        I had the same issue. You can solve it by changing the format as described above:

        Right click cell > Format Cells > (In Number tab) > Custom > Then enter the code [h]:mm
        ([hh]:mm and [hhh]:mm are nice too if you want to show leading zeros)

        • Jack Scarce says:

          Thanks guys, these are the tips I'm looking for.
          ...dividing the number of minutes elapsed by the percent change is my task - "int" is the key this time

  6. Srikanth says:

    It doesnt work for greater than 24 hours
    It returns 1:30 for 25.5 hours. It should have returned 25:30

    Ideally I would right function as
    =QUOTIENT(A1,1)&":"&MOD(A1,1)*60

    • Paula says:

      Sorry, replied to wrong comment....

      ----
      I had the same issue. You can solve it by changing the format as described above:

      Right click cell > Format Cells > (In Number tab) > Custom > Then enter the code [h]:mm
      ([hh]:mm and [hhh]:mm are nice too if you want to show leading zeros)

  7. Daniel says:

    Clever use of MOD here to extract the decimal part of a number. Divide a number containing a decimal by 1 and return the remainder. Humm. Very clever.

  8. Tomer says:

    Thanks very much, extremely useful !

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