Promised Ship/Delivery Date Calculator: Stop Promising Dates You Can't Hit

The problem this kills

A customer asks the question every order hinges on: "when will I get it?" And a rep, under pressure and trying to win the deal, answers from memory or gut feel — "should ship Tuesday, you'll have it by Friday." Nobody checked whether the item is actually in stock, whether the warehouse cutoff for today already passed, whether the inbound PO that's supposed to cover the backorder slipped, or whether Friday is a carrier holiday. The date sounds confident. It's also wrong.

Then the date is wrong in the worst possible place: on the order confirmation the customer is now holding you to. Ops can't hit it. The shipment is "late" against a promise it never agreed to. Someone fields the angry call, issues the credit, and the rep learns nothing because the next quote goes out the same way. Multiply that across every rep, every day, and you've built a reputation for missing dates you set yourself.

The math to get this right isn't hard — it's just spread across five places nobody checks in the moment: a lead-time rule, a cutoff time, today's stock, the next inbound date, and the transit calendar. This tool puts that math in one place, runs it the same way every time, and refuses to let a date hit the order until a human signs off.

What you'll build

A simple internal web app for your order desk. A rep enters the order — the item(s), quantity, ship-from location, and the customer's destination. The calculator pulls your rules and your current stock and inbound-PO dates, and computes a realistic ship date and delivery date. It branches on the real situation: in stock (apply pick/pack lead time and today's carrier cutoff), backorder with a known inbound PO (ship after the inbound lands plus handling), or backorder with no coverage (flag it — don't fabricate a date). It honors holidays and carrier cutoff times so it never promises a ship on a day you don't ship.

The computed date lands as a draft. A reviewer — a planner, lead CSR, or ops supervisor — sees the inputs and the reasoning ("in stock, cutoff already passed today, so ships tomorrow; 3 transit days; arrives Thursday"), adjusts if needed, and approves. Only on approval is the promise date written to the order or quote. The same order ID can't be processed twice. Every calculation, override, and approval is logged.

What's inside the Implementation Plan

The downloadable plan is a step-by-step file you paste into an AI coding agent. It opens by interviewing you about your business — how reps quote dates today, where your lead-time/cutoff/transit rules live and how they're shaped, the real names and codes in your item and warehouse data, your stock and inbound-PO sources, your peak volumes, and the messy exceptions (partial-line orders, multi-warehouse splits, will-call, expedited shipping, slipped inbound dates). It reflects a short tailored spec back to you and waits for your thumbs-up before it builds anything, so the calculator matches your operation — not a generic template.

From there it walks the agent through the data model, importing your rules and stock and inbound dates, the calculation engine (with the in-stock / inbound / no-coverage branches, cutoffs, and holiday calendar), the reviewer approval gate, writing the approved date back to the order, and a clean CSV export. Every step ends with a ready-to-copy prompt. There's a full "No API yet?" path that uses Google Sheet / CSV imports for rules and stock and produces a clean CSV of approved promise dates in the exact columns your order system expects — so you can build and run the whole thing this weekend regardless of what ERP or order system you're on.

The governance it includes (this is the point)

This date goes on a customer-facing order, so the controls aren't optional. The plan builds in login so only your team can use the tool, row-level security so you only ever see your own organization's orders and rules, a complete audit trail of who computed which date, who overrode what, and who approved it, a hard human-approval gate so no promise date is written to an order or quote until a reviewer signs off on the computed date, and duplicate guards keyed on order ID so the same order can't be processed — or promised — twice.

Who it's for

Inside sales reps, customer-service reps, and planners — anyone who has to put a ship-or-delivery date in front of a customer and would rather it be one the warehouse can actually hit. If you can describe your lead times, your cutoff times, and how you handle a backorder, you can build this.

You've got this — start with the plan, paste the first prompt, and answer the interview. You'll be computing your first defensible promise date before the weekend's out.