Home Weekday Before If today is Thursday, 78 days before

If today is Thursday, what day was it 78 days before?

Answer: Wednesday

Weekdays repeat every 7 days. So we only need the remainder after dividing 78 by 7, then move backward that many days from Thursday.

Quick rule:
remainder = 78 mod 7 = 1
move backward 1 day(s) from Thursday
Wednesday

Quick Answer

What is Thursday − 78 days?

These sentences all describe the same result:

If today is Thursday, 78 days before was Wednesday
78 days before Thursday is Wednesday
Thursday − 78 days = Wednesday
The weekday 78 days before Thursday is Wednesday

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Detailed Math (Step-by-Step)

We show the whole operation clearly (modulo 7).

Step 1: Find the remainder

Since weekdays repeat every 7 days: days mod 7 tells us how many steps to move backward.

Days 78
Divide by 7 11 remainder 1
Remainder 1
Meaning: Jump whole weeks first (they don’t change the weekday), then move the remainder days backward.

Step 2: Move backward 1 day(s)

Start at Thursday and count backward 1 step(s).

Step Weekday
0Thursday (start)
1Wednesday (result)
Final: Thursday − 78 days = Wednesday
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Quick Lookup Table

Common values going backward from Thursday.

Days before Thursday Weekday Remainder (mod 7)
0 Thursday 0
1 Wednesday 1
2 Tuesday 2
3 Monday 3
4 Sunday 4
5 Saturday 5
6 Friday 6
7 Thursday 0
8 Wednesday 1
9 Tuesday 2
10 Monday 3
14 Thursday 0
21 Thursday 0
28 Thursday 0
30 Tuesday 2
78 Wednesday 1

Tip: Any number of days that differs by a multiple of 7 lands on the same weekday.

Instant Calculator

Change weekday and day count to see the result immediately.

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More “Weekday Before” Examples

Check other weekday calculations going backward in time.