Guides

How to keep the promises you make in email and Slack

Updated October 21, 2026

Short answer: Every “I’ll…” you write with a day in it is a commitment the other person will remember. Give it a real day, and put it where you look each morning the moment you send it. When it’s done, reply in the same thread so they know. A tool that reads your sent mail can do the catching for you.

Most of what you owe people isn’t in a task list. It’s in your sent mail: “I’ll get back to you tomorrow with the numbers,” “let me check with legal and circle back this week,” “I’ll send the deck over by Friday.” You meant every one of them. But a sent email leaves no reminder behind, and the other person is the only one keeping track.

Why written promises slip

• They’re made in the middle of something else: a reply to a question, a thread about something bigger.
• Sent mail is out of sight. You read your inbox every day; you almost never reread what you sent.
• The day is in the sentence, not on a calendar. “By Friday” means nothing to any tool that doesn’t read it.
• Slack is worse: a promise in a DM scrolls away within the hour.

A habit that works

1. Give every promise a day. “Soon” and “this week” turn into nothing; “Thursday” gets done.
2. Before you press Send, put it where you look each morning: your calendar, your list, or a note to yourself with the date.
3. If you can do it in two minutes, do it instead of promising it.
4. When it’s done, reply in the same thread. Keeping a promise counts when they can see you kept it.
5. If it’s going to be late, say so before the day, not after.

The ones that repeat

Some promises come back every week or month: the investor update, payroll, the Friday note to your team. Write those down once as recurring, so the next one shows up on its day instead of when someone asks where it is.

What to do when you’ve already dropped one

Send it now, with one line that owns the delay (“Sorry this is late, here’s the deck”), and no long apology. Most people remember that you followed through far longer than that you were a few days late.