Sibling / Multi-Child Discount

Excel Formulas › Childcare & Daycare

All versionsSUMPRODUCT

Families with multiple children get a sibling discount — often a percentage off the second (and later) child. Summing each child’s tuition with the right discount gives the family total.


Quick formula: family total with a sibling discount:
=oldest_tuition + others_tuition*(1 - sibling_discount)
Charge the highest tuition in full and apply the discount to the remaining children's tuition.

Functions used (tap for the full reference guide):

The example

$320 + $280, 10% off 2nd.

AB
1ItemValue
2320 + 280×0.9—
3Family total→ $572

The formula

The formula:

=full_tuition + others * (1 - sibling_discount) // full first child, discount the rest

How it works

How it works:

  1. Charge the first child (usually the highest tuition) at full rate.
  2. Apply the discount to each additional child’s tuition.
  3. For many children, SUMPRODUCT(tuitions, discount_factors) handles it in one cell.
  4. Decide whether the discount applies to the oldest or the lowest tuition — it changes the total.

Which child gets the discount matters. Discounting the second-enrolled child versus the lowest-tuition child gives different family totals — and since infant tuition is highest, applying the discount to the cheaper preschool spot costs the family more. State the rule clearly and encode it consistently. A discount-factor column (1.0 for full, 0.9 for discounted) plus SUMPRODUCT makes any policy a one-cell calc.

Try it: interactive demo

Live demo

First child tuition, others total, discount %.

Family total · Saved

Variations

Many children

Discount factors:

=SUMPRODUCT(tuitions, discount_factors)

Amount saved

The discount:

=others * sibling_discount

Flat per-sibling discount

Dollar, not percent:

=total_tuition - (siblings) * flat_discount

Pitfalls & errors

Which child. Discount the second-enrolled or the lowest tuition — decide and document.

Percent as decimal. 10% is 0.10.

Per child. Apply the discount per additional child, not once.

Practice workbook

📊
Download the free Sibling / Multi-Child Discount practice workbook
A sibling-discount sheet with the many-children, saved, and flat variants, plus 4 challenges with answers. No sign-up required.

Frequently asked questions

How do I calculate a sibling discount in Excel?
Full tuition for the first child plus discounted others: =full_tuition + others * (1 - sibling_discount). $320 + $280×0.9 is $572.
How do I handle many children?
Use SUMPRODUCT of tuitions and discount factors (1.0 full, 0.9 discounted).
Which child should get the discount?
Decide between second-enrolled and lowest-tuition — it changes the family total since infant tuition is highest.

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Related formulas: Tuition by age group · Quantity discount pricing · Product of a range

Function references: SUMPRODUCT