Home › Weekday Before › If today is Thursday, 13 days before
Quick Answer
What is Thursday − 13 days?
These sentences all describe the same result:
If today is Thursday, 13 days before was Friday
13 days before Thursday is Friday
Thursday − 13 days = Friday
The weekday 13 days before Thursday is Friday
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 | 13 |
|---|---|
| Divide by 7 | 1 remainder 6 |
| Remainder | 6 |
Step 2: Move backward 6 day(s)
Start at Thursday and count backward 6 step(s).
| Step | Weekday |
|---|---|
| 0 | Thursday (start) |
| 1 | Wednesday |
| 2 | Tuesday |
| 3 | Monday |
| 4 | Sunday |
| 5 | Saturday |
| 6 | Friday (result) |
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 |
| 13 | Friday | 6 |
| 14 | Thursday | 0 |
| 21 | Thursday | 0 |
| 28 | Thursday | 0 |
| 30 | Tuesday | 2 |
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.
More “Weekday Before” Examples
Check other weekday calculations going backward in time.