What this tool does
Most cut-off tables are forward-looking: they tell you when an order placed today will arrive. This solves the other direction. Give it the date the parcel must be on site, the courier's transit time, your own handling time and the courier's closed days, and it walks backwards to the last date the order can be placed, showing every step of the chain instead of asserting a single number.
How it works
The solve runs backwards through four stages. First the target date is snapped off the courier's non-delivery days: if the parcel must arrive on a Sunday, or on a day you have listed as a courier or bank holiday, it is delivered on the working day before. That step is the one hardcoded tables skip, and it is the difference between a cut-off that works and one that is a day late without anyone noticing.
Second, any safety buffer is subtracted in working days. Third, the courier's transit time comes off, again in working days, so a Sunday in the middle of the route costs you a day of real time. Fourth, your own handling, which means picking, packing, invoicing and handing over, is subtracted as business days rather than calendar days, which is the difference between a warehouse that closes on Sunday and one that does not.
The Saturday-moves-to-Monday pattern is modelled as a documented handover rule rather than a plain walk. The courier still collects on Saturday and the parcel sits in the hub over Sunday, so a Monday delivery has already spent one transit day getting there, and the walk starts from that Saturday with the day already deducted. Many Indian domestic services quote exactly this, and the derivation differs enough that folding it into an ordinary weekend would be quietly wrong.
Festival dates are a convenience, not an authority. Diwali 2026 is 8 November, which is a Sunday, and Dhanteras is 5 November, but these are lunisolar: they depend on the local panchang, the region and the amanta or purnimanta convention, and published sources disagree by a day. They ship as editable fields with no claim to have been verified, and the last week before a festival is not a reliable delivery window whatever the arithmetic says.
Worked example
A parcel must reach the customer by Diwali, Sunday 8 November 2026. The courier delivers Monday to Saturday, transit is 3 working days, your handling is 1 working day, there is 1 day of buffer, and 5 and 8 November are on the holiday list.
- 8 November 2026 is a Sunday and is on the holiday list, so delivery moves back to Saturday 7 November
- One buffer working day back from Saturday 7 November is Friday 6 November
- Three transit working days back from Friday 6 November skips the 5 November holiday, so the courier handover is Monday 2 November
- One handling working day back from Monday 2 November, skipping Sunday, is Saturday 31 October
The last date to place the order is 31 October 2026, 7 calendar days of lead time, and the parcel lands on 7 November, the day before the festival rather than on it.
Accuracy and limitations
- Festival dates are lunisolar and cannot be derived from a rule. The bundled 2026 dates are a starting point; verify them against your courier, your bank and your local calendar before publishing a cut-off to customers.
- Every courier publishes its own cut-off time of day and its own closed days, and neither is the same as the transit time in its own calculator. Confirm both with them.
- This is calendar arithmetic. It knows nothing about hub capacity, road conditions, cash on delivery remittance timing, or what actually happens in peak week.
Frequently asked questions
- What is the last date I can place the order?
- It is the date the backward chain produces when you supply a delivery target, transit days, handling days and the courier's closed days, and every step is shown so you can check it. In practice plan for an earlier date than the answer, because couriers slip in peak weeks without warning and do not refund the difference.
- Why did the delivery date move back by a day?
- Because the date you asked for is one the courier does not deliver on, most often a Sunday or a holiday you listed. The parcel then has to be delivered on the working day before, and the whole chain is counted back from there rather than from your original target date. This is the step that hardcoded tables get wrong.
- Is the Diwali date built in?
- Diwali 2026 is bundled as 8 November and Dhanteras as 5 November, and both fields are editable. These are lunisolar dates that depend on the local panchang and the region, so treat them as a convenience to be verified rather than an authority, and check your courier's own festival cut-off as well.
- Are handling days calendar days or working days?
- Working days, counted on the same weekend pattern and the same holiday list as the transit. A one-day handling time in a Sunday-off week can consume three calendar days, which is why a lead time borrowed from a five-day-week operation will understate the real one.
- How is the Saturday to Monday handover handled?
- Many Indian domestic services collect on Saturday, hold the parcel over Sunday and deliver on Monday. That is modelled as a handover rule: the Monday delivery has already spent one transit day, so the backward walk starts from the preceding Saturday with that day deducted, rather than treating it as an ordinary closed weekend.