Anyone managing subscriptions on behalf of customers knows the quiet dread of a renewal date sneaking up unnoticed. The start date and the plan length are both sitting right there in the spreadsheet, but turning those two facts into "renews in 4 days" still takes someone actually doing the subtraction — and remembering to do it again tomorrow, and the day after that.

In this tutorial, we'll build a Subscription Renewal Countdown — a table that calculates exactly how many days remain until each subscription renews, recalculated fresh every single day, with zero manual math involved.

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Table Columns

Here's what we're working with — a Subscription table with Customer Name, Plan, Start Date, and Duration (in days).

Subscription table columns showing Customer Name, Plan, Start Date, and Duration fields

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Step 1: Add Your Subscriptions

Add a handful of subscriptions with different start dates and durations, so we can see the countdown behave once it's built.

Subscription table populated with sample subscriptions for three different customers

For this walkthrough, assume today is August 30, 2026, and we have:

• Hana Kobayashi — Monthly plan, started August 3, 2026, Duration 30 days
• Oscar Lindqvist — Annual plan, started September 15, 2025, Duration 365 days
• Ines Duarte — Monthly plan, started August 28, 2026, Duration 30 days

Right now, none of these rows tell you how urgent any of them are — you'd have to calculate the renewal date yourself, then subtract today's date from it, for every single row.

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Step 2: Calculate Days Until Renewal

Since a plain column can't be converted into Custom Logic after the fact, create a brand new column and set its type to Custom Logic from the start.

Adding a new Custom Logic column for Days Until Renewal

Describe what you want — add Duration to Start Date to find the renewal date, then calculate how many days remain between today and that renewal date.

Describing the logic to calculate days remaining until Start Date plus Duration

Confirm the clarification screen, checking that it correctly chained both steps together — first finding the renewal date, then measuring the gap to today.

Clarification screen confirming the two-step calculation of renewal date and days remaining

Save it, and the countdown fills in instantly for every row:

• Hana Kobayashi → renews September 2, 2026 → 3 days
• Oscar Lindqvist → renews September 15, 2026 → 16 days
• Ines Duarte → renews September 27, 2026 → 28 days

Subscription table showing Days Until Renewal calculated for every subscriber

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Step 3: Watch the Countdown Move Overnight

To see this in action without waiting around, imagine opening the table again the next day, August 31, 2026.

Hana Kobayashi's countdown changes from 3 days → 2 days, automatically.

Oscar Lindqvist's countdown changes from 16 days → 15 days, automatically.

Subscription table showing all Days Until Renewal counts decreased by one after a day has passed

Now suppose Hana renews early. Update her Start Date to reflect the new cycle, from August 3, 2026 → August 31, 2026.

Updating Hana Kobayashi's Start Date to reflect an early renewal

Her countdown jumps back up immediately.

Hana Kobayashi's countdown changes from 2 days → 30 days, without touching any other field.

Hana Kobayashi's Days Until Renewal reset to 30 after her Start Date was updated

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Step 4: Build a View for Upcoming Renewals

A countdown per row is useful, but what you actually want day-to-day is a short list of who's renewing soon. Create a new view, filter where Days Until Renewal is less than or equal to 7, sort ascending, and save it as "Renewing This Week."

Saved filtered view named Renewing This Week showing subscriptions with 7 or fewer days remaining

Only Hana Kobayashi's original entry would have appeared here before her renewal — now, after her update, the view naturally reflects whoever's actually close to their renewal date at any given moment.

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Recap

1. A Subscription table with Start Date and Duration
2. A Custom Logic field chaining two calculations — renewal date, then days remaining — recalculated live every day
3. A live demonstration of the countdown decreasing overnight and resetting after a renewal
4. A filtered view surfacing only the subscribers renewing within the next week

This same countdown pattern extends well beyond subscriptions — contract renewals, warranty expirations, or trial periods can all be tracked the same way, anywhere "time remaining" needs to stay accurate without manual upkeep.