⚗️ Lesson 4.2: Practical Formula Patterns (with Optional Deep-Dive)

How to Use This Cookbook

Treat these like kitchen recipes. You don't reinvent bread every morning — you follow a recipe and tweak the salt. Formulas are the same: the community and Notion's own docs are full of proven patterns, and the skill that matters is adapting one to your property names, not composing from scratch.

For each recipe below:

1. Read the plain-English line to see what it does.
2. Copy the code into a Formula property.
3. Swap the property names (prop("Due"), prop("Done"), etc.) for whatever yours are called — use autocomplete so they're spelled right.
4. Check the result and adjust the words/emoji to taste.

Dates & Deadlines Recipes

🗓️ Days until due (or days overdue)

Shows how many days until the Due date; negative means overdue.

dateBetween(prop("Due"), now(), "days")

A friendlier, wordier version that handles a missing date:

if(empty(prop("Due")),
   "No due date",
   format(dateBetween(prop("Due"), now(), "days")) + " days left")

⚠️ Overdue flag

Marks unfinished tasks whose Due date has passed.

if(prop("Done"), "",
   if(prop("Due") < now(), "⚠️ Overdue", ""))

🔁 Next review date (spaced-repetition-ish)

Adds an interval (in days) to the last reviewed date to suggest when to review again.

dateAdd(prop("Last reviewed"), prop("Interval (days)"), "days")

Pair it with a "due for review?" check:

if(dateAdd(prop("Last reviewed"), prop("Interval (days)"), "days") <= now(),
   "📚 Review now", "✅ Up to date")

⏱️ Duration between two dates

How long a project ran, in days.

if(empty(prop("Start")) or empty(prop("End")),
   "",
   format(dateBetween(prop("End"), prop("Start"), "days")) + " days")

Status & Indicator Recipes

🏷️ Auto status label

One clear label combining Done, missing date, overdue, and on-track.

ifs(
   prop("Done"), "✅ Done",
   empty(prop("Due")), "🗓️ No date",
   prop("Due") < now(), "⚠️ Overdue",
   "🟢 On track"
)

🔴🟡🟢 Conditional emoji indicator

A traffic light from a number (e.g. days left or a priority score).

ifs(
   dateBetween(prop("Due"), now(), "days") < 0, "🔴",
   dateBetween(prop("Due"), now(), "days") <= 2, "🟡",
   "🟢"
)

Read it: overdue → red, due within two days → yellow, otherwise green. Swap the numbers to taste.

⭐ Priority stars from a number

Turns a 1–3 priority number into stars.

ifs(
   prop("Priority") >= 3, "⭐⭐⭐",
   prop("Priority") == 2, "⭐⭐",
   "⭐"
)

Progress Bar from a Rollup

Remember the "% complete" rollup from Lesson 3.5? A formula can turn that number into a little visual bar made of block characters — no images, no add-ons. Here's the everyday pattern:

// prop("% complete") is a rollup returning 0–1 (a percent)
// Build a 10-slot bar of filled/empty squares
slice("🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩", 0, round(prop("% complete") * 10) * 2)
  + slice("⬜⬜⬜⬜⬜⬜⬜⬜⬜⬜", 0, (10 - round(prop("% complete") * 10)) * 2)
  + " " + format(round(prop("% complete") * 100)) + "%"

In plain English: take up to ten 🟩 for the completed share, fill the rest with ⬜, and tack the percentage on the end. A project that's 30% done shows 🟩🟩🟩⬜⬜⬜⬜⬜⬜⬜ 30%. (The * 2 is because each emoji square counts as two characters to slice.)

Prefer something shorter? A minimalist bar:

let(pct, round(prop("% complete") * 10),
   slice("██████████", 0, pct) + slice("░░░░░░░░░░", 0, 10 - pct))

(This one uses let() to name the value once — covered in the optional section below.)

Text & Combining Recipes

🧩 Combine text (full name / label)

Glue several properties into one readable string.

prop("First") + " " + prop("Last")

// with a fallback if a piece is blank:
if(empty(prop("Nickname")), prop("First"), prop("Nickname"))

🏷️ Label with a number folded in

Remember to format() the number before joining it to words.

prop("Project") + " — " + format(prop("Task count")) + " tasks"

✂️ Trim a long title for cards

Show the first 40 characters with an ellipsis if longer.

if(length(prop("Task")) > 40,
   slice(prop("Task"), 0, 40) + "…",
   prop("Task"))

🔎 Tag detector

Flag rows whose title mentions something.

if(prop("Task").lower().contains("call"), "📞", "")

🎯 Project: Add Two Recipes

Pick two recipes and add them to your system — one progress bar and one status/indicator formula. Both work on the Free plan. Building them cements the copy-adapt-verify habit that makes formulas painless forever.

// Progress bar (Projects) — "% complete" is a 0–1 rollup
slice("🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩", 0, round(prop("% complete") * 10) * 2)
  + slice("⬜⬜⬜⬜⬜⬜⬜⬜⬜⬜", 0, (10 - round(prop("% complete") * 10)) * 2)
  + " " + format(round(prop("% complete") * 100)) + "%"

// Indicator (Tasks)
ifs(
   prop("Done"), "✅",
   empty(prop("Due")), "⚪",
   dateBetween(prop("Due"), now(), "days") < 0, "🔴",
   dateBetween(prop("Due"), now(), "days") <= 2, "🟡",
   "🟢"
)

Best Practices for Formula Patterns

✅ Do's

• Keep a personal formula stash — a Notion page of recipes you reuse.
• Verify the raw value (with format()) when a recipe behaves oddly.
• Favor the simplest recipe that works over a clever one you can't reread later.

❌ Don'ts

• Don't treat the deep-dive as required. Lists and let() are bonuses.
• Don't paste without swapping property names — that's the #1 cause of errors.
• Don't build a monster formula when a rollup or button would do the job cleanly.

📓 Learning Journal

📝 Lesson Summary

🎉 What You've Accomplished

You now have real, working formulas in your workspace and a repeatable way to add more: copy, adapt, verify. That's the professional workflow — nobody writes these cold. Your system just got a lot more informative, and you didn't have to become a programmer to do it.

❓ Common Questions at This Stage

🔭 Looking Ahead

You've made databases smart. Next we make them reusable: Templates — Reuse Everything. You'll learn to save a page or database row as a template so you can spin up a new project, meeting note, or habit tracker in one click — with your formulas and structure already in place.

✅ Before the Next Lesson

• Keep your progress bar and indicator formulas — templates will reuse this structure
• Save your two recipes into a "Formulas" note for future copy-paste
• Write your Learning Journal entry for this lesson

📚 Additional Resources

• Notion Help — Formulas
• Notion Developers (for the truly curious)
• r/Notion — a great place to find and share formula recipes