Send the delay email the day you know about the delay, include a new date you can actually keep, and say what you need from the client to hit it. That is the whole rule. The four templates below cover the four causes of delay (your side, the client's side, a supplier or weather, and a change in scope), then a short rule for choosing the new date, a text version, and what to do if the date slips again.
Clients rarely mind a delay as much as they mind finding out late, or being given a date that then moves. A message sent the day you know costs you a little pride. A message sent after the missed date costs you trust, and it makes the client wonder what else you haven't told them. If you also need a general check-in for projects in progress, see checking in with a client by email.
Send it the day you know
The clock starts when you learn the delay is likely, not when it becomes certain. If you are 70 percent sure a Friday delivery will slip, write on Wednesday. Say "I expect" instead of "I promise," and tell them when you'll confirm. Clients plan around your dates: a launch announcement, a crew schedule, a move. Two days of notice lets them adjust, and one hour does not.
Every template below follows the same order: what happened in one sentence, the new date, what it affects, what you need, and when they'll hear from you next. Keep it under 120 words. Long explanations read as excuses.
When the delay is yours
Own it in the first sentence. No passive voice, no "unforeseen circumstances."
Subject: Your site launch is moving from Oct 16 to Oct 23
Hi Dana, I underestimated the checkout setup, and it won't be ready by Friday. The new launch date is Friday, October 23. Everything else is on track: the pages are done and approved. Nothing needed from you right now. I'll send you the checkout link for testing on Tuesday the 20th. I'm sorry for the shift, and I'd rather tell you now than on Thursday night.
Marcus
Why it works: "I underestimated" is a reason that doesn't blame anyone, the date is specific, and it says what stays the same. Variation: if the delay costs the client money (a missed promotion, a rental), offer what you can: a discount, a weekend of your time, a temporary workaround. Don't offer what you can't deliver.
When the delay is on the client's side
Be factual and kind. Show the dependency and the date it moves to.
Subject: We need the logo files by Wednesday to keep the Nov 2 date
Hi Priya, we're ready to begin the signage layout, but the logo files haven't arrived. If I have them by Wednesday, October 14, we stay on track for November 2. For each day after Wednesday, the date moves by one working day, because the print slot is booked. I've attached a list of the three files I need, with a one-click upload link. Reply here if any of them are hard to find and I'll help.
The "one working day for each day" line is the key. It turns your delay from a mystery into arithmetic they control. For a client who is slow with documents, email to a client requesting documents has the full set of requests and reminders.
When a supplier or weather is the cause
Name the cause and the evidence, briefly. A cabinet supplier delayed an order; a storm closed a site. Don't blame a person by name.
Subject: Kitchen cabinets are delayed 2 weeks by the supplier
Hi Gordon, the cabinet maker told us this morning that the doors are delayed by 14 days. The new delivery is October 30, so installation moves from October 21 to November 4. I've kept your crew dates open and will confirm the supplier's ship date again on the 25th. Your countertop template appointment stays where it is. Can you confirm that November 4 works for you?
Ask a yes-or-no question at the end, because a client needs to confirm the new date. If weather is the cause, give the forecast window and what you'll do, such as "the first dry day after Wednesday." For a related pack that covers the other direction, estimate follow-up for contractors shows how to keep a quote from going cold.
When scope changed
Be careful here, because it's the most likely to cause a fight. Link the delay to the change the client asked for, and show both choices.
Subject: Adding the second landing page moves delivery by 4 days
Hi Sam, you asked on Monday for a second landing page. That is outside the original three pages, and it adds four working days. Option A: we include it, and delivery moves from October 19 to October 23, for an added $450. Option B: we deliver the original three pages on October 19 and build the extra page next, for the same $450, on October 26. Reply A or B by Thursday and I'll start.
The A or B format avoids "you caused the delay" and gives the client control. The scope document you wrote at the start is what makes this easy; the scope of work template shows how to write one.
Picking a new date you can keep
The rule: take your honest estimate of the remaining work, add 25 percent, and round up to the next working day. If you think 8 working days remain, add 2, and say 10. Then name the one thing that could move the date. Example: 8 days of work left, starting Monday, October 12. Ten working days takes you to Friday, October 23. That's the date you give. If you finish early, you've delivered ahead of the promise, and the client remembers that. If you give your best case, you will send a second delay email.
Also tell them when you'll confirm: "I'll confirm Tuesday that we're still on track." A scheduled confirmation prevents a second anxious email from the client.
A text version, and what to do if the new date slips
Text is for urgent changes within 48 hours of a date, and only for clients who have texted you first. Keep it to two lines: "Hi Dana, it's Marcus. Checkout isn't ready for Friday. New date is Oct 23, details in your email." Then send the email. More examples in professional text message examples for business.
If the new date slips again, call, don't email. Say: "I gave you a date I should have padded. Here's what's different now, here's a new date with a buffer, and here's what I'll do about the cost." Then follow with a short email. A second slip with a call and a real change in the plan is recoverable. A third is a pattern, and the client is right to ask what is going on.
Projects that run on time are easier when the work you're taking on is steady. Rocketship finds the buyers, emails them from your own Gmail, follows up, and books the meeting on its own. Plans that get you customers start at $24.99 a month (Launch), and both Launch and Frontier start with a 7-day free trial, card required. Also see how to handle a difficult client and the client onboarding checklist.