Two saving percentages cannot always be averaged directly
By Erik Nilsen · Kroni2 min read
When your child receives different amounts in two periods, calculate the combined saving share from the combined money. Simply averaging the percentages gives equal weight to each period despite one containing much more money.
Add money before finding the combined percentage
In a hypothetical example, your child receives 100 units in the first period and saves 10. In the second they receive 20 and save 10. The arbitrary amounts are invented, with allocations agreed within the family.
The first saving share is 10 / 100 = 10 per cent. The second is 10 / 20 = 50 per cent. A simple average produces (10 + 50) / 2 = 30 per cent.
However, your child received 100 + 20 = 120 altogether and saved 10 + 10 = 20. The combined share is 20 / 120, approximately 16.7 per cent. Thirty per cent of 120 would be 36, exceeding actual saving by 16.
Retain each period's base amount
A practical snag is copying only the percentages into a summary while losing the received totals. Put received and saved amounts on the same row for each period. Add both columns before dividing.
If the received totals were equal, a simple average of the percentages could give the correct combined share. Here they differ, with the first period accounting for five times the received money of the second.
The combined percentage describes what happened rather than creating a new agreement or contribution. Do not alter historical saving to make it match 30 per cent. If your family wants another rate in future, make a new plan for money received then.
Ask your family: “Have we added actual received and saved amounts before calculating one combined percentage?”
Clarify what the virtual balance represents
Kroni keeps track using a virtual balance and does not transfer money. Cash your child has received and amounts an adult still owes are different things. This exercise concerns money actually received. Agree how it fits your record so the same amount is not counted both as received and still unpaid. Read about allowance in Kroni.
