Free tool
Where do your 28-day cycles fall?
Portable-sanitation billing runs on 28-day cycles — thirteen a year, not twelve calendar months. Pick an anchor date and see every cycle. In SwapProof, each cycle closes into an invoice PDF, your own payment link, and dunning reminders — automatically.
| Cycle | Starts | Ends | Invoice due |
|---|---|---|---|
| 1 | Mon, Apr 6 | Sun, May 3 | Sun, May 3 |
| 2 | Mon, May 4 | Sun, May 31 | Sun, May 31 |
| 3 | Mon, Jun 1 | Sun, Jun 28 | Sun, Jun 28 |
| 4 | Mon, Jun 29 | Sun, Jul 26 | Sun, Jul 26 |
| 5 | Mon, Jul 27 | Sun, Aug 23 | Sun, Aug 23 |
| 6 | Mon, Aug 24 | Sun, Sep 20 | Sun, Sep 20 |
| 7 | Mon, Sep 21 | Sun, Oct 18 | Sun, Oct 18 |
| 8 | Mon, Oct 19 | Sun, Nov 15 | Sun, Nov 15 |
| 9 | Mon, Nov 16 | Sun, Dec 13 | Sun, Dec 13 |
| 10 | Mon, Dec 14 | Sun, Jan 10 | Sun, Jan 10 |
| 11 | Mon, Jan 11 | Sun, Feb 7 | Sun, Feb 7 |
| 12 | Mon, Feb 8 | Sun, Mar 7 | Sun, Mar 7 |
| 13 | Mon, Mar 8 | Sun, Apr 4 | Sun, Apr 4 |
Thirteen 28-day cycles from your anchor. Change the date to see them shift.
Let the cycles bill themselves.
SwapProof turns each 28-day cycle into an invoice, a payment link, and dunning reminders — the money lands in your own account. Free to start.