- What's the difference between INT and TRUNC?
- INT always rounds down toward negative infinity (INT(-3.2) = -4), while TRUNC removes decimals toward zero (TRUNC(-3.2) = -3). For positive numbers, both behave the same. Use INT when you want consistent downward rounding; use TRUNC when you want to simply strip decimals without direction bias.
- Why does INT(-3.7) return -4 and not -3?
- INT rounds toward negative infinity, not toward zero. Since -4 is further down the number line than -3, it is the 'lower' value, making it the correct result for INT's rounding rule. This behavior is intentional and consistent: INT always produces the largest integer that is less than or equal to the input.
- Can I use INT inside other formulas like SUMPRODUCT or array formulas?
- Yes. INT works inside SUMPRODUCT, conditional IF statements, and array formulas: =SUMPRODUCT(INT(A1:A10)*B1:B10) will round down each value in A1:A10 before multiplying by B1:B10. This is common when you need to round down fractional quantities before using them in calculations.
- When should I use INT instead of just accepting decimal values?
- Use INT when inventory, billing, or reporting rules require whole units only. Decimal quantities are common in manufacturing (45.7 kg), but warehousing and shipping often demand whole units. INT also improves readability in reports and prevents fractional billing. For calculations that stay within your system, decimals are fine—use INT only when output must be whole.