How long is a time capsule usually sealed for?

The three most common horizons are one year (for young children, where it can become a yearly ritual), ten years, and the 18th birthday. The longer the gap, the more important a dry spot inside your home is, along with a note about the capsule in your family's important papers so it doesn't get forgotten.

Can you bury a time capsule in the yard?

You can, but you need a waterproof container, a depth below the frost line, the spot recorded from two fixed landmarks, and the certainty that you'll still own the property in ten years. For paper and photos, a box in a closet is safer; the ground is better suited to items that moisture won't harm.

What should I write in a letter to a baby who's just a few months old?

Describe the day, not your feelings. Where you live, what the room looks like, what time your baby falls asleep, what makes them laugh, what the neighbor's name is. General wishes age; specific everyday details are the only thing nobody would otherwise remember eighteen years from now.

How many things should go in the capsule?

Three to five items, five to ten printed photos, and one single-page letter. An overstuffed box is harder to close and to preserve, and when it's opened, what matters gets lost. If the box is half empty, fill it out with clean paper so the contents don't shift.

How do you keep someone from opening the capsule early?

The most reliable way is a list of contents and the opening date written on the outside of the lid — most early openings come from uncertainty about what's inside. A simple seal or a wrap of tape takes care of the rest: the goal isn't a vault, just a small obstacle that makes people stop and think.

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Letter to the Future & Time Capsule: What and When

2/09/2026 · The Hero of the Book Team

A time capsule in one afternoon: what goes inside, how to write a letter to the future, and when to open it so it's still readable years later.

Letter to the Future & Time Capsule: What and When

Quick answer

A time capsule is a sealed box of everyday things from today that your family opens on a date agreed in advance, and a letter to the future is the most precious thing inside it. You can put one together in a single afternoon: a well-sealing box or tin, three to five items that look completely ordinary today, printed photos, and a handwritten page about what life at your house is like right now.

The only decision worth making right at the start is the opening date. Write it on the outside of the lid and put it on the family calendar, or else someone will open the capsule "just to peek," or it'll be forgotten ten years from now.

A time capsule in one afternoon: step by step

The order isn't random. Most capsules that end up half-finished in a drawer stall at the step where everyone gathers nice keepsakes and the letter gets put off until later.

1
Agree on an opening date
Before you start collecting anything, say out loud when the capsule will be opened: a specific year, ideally tied to an event (an 18th birthday, finishing middle school, ten years from today). The date determines everything else, especially how carefully the capsule needs to be stored.
2
Choose a container based on where it will live
For a closet, a sturdy box with a lid or a cookie tin is enough. A basement, garage, or the ground calls for a container that truly seals, because moisture is more dangerous to paper and photos than time. Pick a container a couple of inches bigger than the largest sheet of paper going in: nothing should have to be folded to fit.
3
Write the letter first
The letter is the one thing nobody else can write. Give it twenty minutes and a single page, not a half-filled notebook.
4
Add three to five everyday items
Not the nicest things in your home, but the most ordinary: a bus ticket, a grocery receipt, a drawing made that day, a stub from a movie ticket. Ten years from now, it's exactly this everyday stuff that's interesting, not a carefully chosen souvenir.
5
Print photos and write who and when on each
Photos on your phone won't make it into the capsule. Print five to ten shots and write the name, place, and date on the back in soft pencil. Without captions, fifteen years from now half the people in the photos will be unrecognizable, even to your own family.
6
Make a list of the contents and tape it to the outside
Two things belong on the lid: the opening date and a short list of what's inside. The list keeps anyone from opening the capsule early just because they can't remember whether there are important documents in it.
7
Seal it and tell one more person about it
A capsule only one person knows about gets lost in the first move. Tell your partner, a sibling, or a grandparent about it, and add a note to your family's important papers.

A letter to the future: paragraphs to borrow

The first sentence is the hardest. The paragraphs below are meant to be copied and filled in; replace the parentheses with your own words. The best letters aren't wise, they're specific: the price of a loaf of bread, the babysitter's name, the phrase your child kept repeating that week.

A parent to a child turning 18

"I'm writing to you in (month and year), and you're (age). This morning you (what they were doing), and you said to me: (something your child actually said). I don't know what you're like now, but I know what it was like to have you at home this year — and I wanted you to know it too."

To a baby who'll read this years from now

"When you read this, you'll be more years old than I can even imagine today. We live at (address), you sleep in a room with (description), and you love falling asleep while we sing you (song). Here's what your day looks like: (three sentences about an ordinary day)."

To yourself in ten years

"Right now I'm preoccupied with (one worry), and I think that in ten years (prediction). When you read this, check whether it turned out that way. What I want most today is (wish), and what I'm afraid of is (fear)."

A grandparent to a grandchild

"At your age, I (what they did, where they lived). Things you take for granted today didn't exist in our home: (two specific things). I want you to know one family story that nobody else will tell you: (a five-sentence story)."

A last paragraph to end on

"I don't know what has happened between today and the moment you read this. But this day, (date), was ordinary, and it was good. Signed: (name), (date)."

What belongs in the capsule and what will ruin it

Papers that look worthless today
A receipt with prices, a ticket, a flyer from an after-school activity, a class schedule, a printed order confirmation. These are what get read most years later, precisely because nobody keeps them. Thermal-paper receipts fade to blank within a few years, though, so take a photo of them or copy the total in pencil in the margin.
A hand tracing, height, a dated drawing
A traced hand on paper weighs nothing, and ten years later it's the most convincing proof of how little your child was. A more durable option is a handprint or footprint, but it deserves its own sleeve so it doesn't rub against the papers in the box.
Printed photos, not just files
A printed photo is the only thing in the capsule you don't need any device to open. Keep the photos in their own envelope, not loose among the papers, ideally in a sleeve labeled acid-free.
Sound, if you can save it twice
A recording of your child's voice or a story read aloud is the most powerful thing in the capsule and also the most fragile. It belongs in the box only as an extra copy; the main copy has to stay outside on a drive that gets used regularly.
Nothing that can leak, rot, or swell
Candy, seeds, perfume, balloons, rubber toys, batteries. Rubber and balloons break down into a sticky mess, and batteries leak and corrode everything around them. A flower can go inside only if it's dried and layered between sheets of clean paper.
Newspaper and tape
A newspaper from the day your child was born is a lovely idea, but acidic newsprint yellows and transfers onto everything it touches. Put it in a separate envelope. Never repair photos or documents with tape; over the years the adhesive seeps through.
The only copy of anything
The capsule is no place for the only print of a photo, the only original of a document, or a flash drive holding the only copy of a video. The capsule is a gift, not an archive.

When to open it: four timelines and what suits each

Opening date	Best for	What to add	What to watch for
In a year, on the next birthday	A preschooler, for whom a year is forever	A height chart, a drawing, a photo from the same spot and the same angle	A short gap means a small change. Make it a series and add to the capsule every year.
In ten years	A school-age child who'll open it as a teenager	A list of friends, favorite songs, prices of everyday things, a weekly schedule	It has to survive a move. Label the box on the outside and add a note about it to your family's important papers.
On the 18th birthday	A newborn, and a letter from the parents	The hospital bracelet, a separate letter from each parent, a newspaper from the birth date	The longest window demands the best storage. Put the newspaper in its own envelope.
At a wedding or the birth of their own child	Grown children, with grandparents as the writers	A family recipe, a photo of the house, a letter about what life was like before the kids came	The date isn't certain and may never come. Write a backup date on the lid too, such as a 30th birthday.

Where to store it so it's still readable years later

The enemy isn't time, it's moisture and temperature swings. The U.S. National Archives recommends keeping family papers and photos below 75 °F and below 65% relative humidity, because mold grows above that threshold, while also avoiding very dry conditions under 15% humidity, where paper becomes brittle. A damp basement, a garage, and a sweltering attic are therefore the three worst places, even though they're the ones people choose most often.

A good spot is inside your living space: the top shelf of a closet, the space under a bed, a storage closet. Set the box on a shelf, not directly on the floor, and away from pipes, windows, and anywhere that has ever leaked. Inside, use acid-free, low-lignin sleeves and folders, and don't bend anything to make it fit. If the box is half empty, fill it out with clean paper so the contents don't slide around.

Burying it in the yard is possible, but it's a different discipline: you need a truly waterproof container, a depth below the frost line, a precise record of the spot, and the certainty that the property will still be yours in ten years. For most families, a box in the closet works better.

And one last thing people forget: what you write with. An ordinary soft pencil and pigment ink will last; gel pens, highlighters, and stamp-pad ink fade. Always write on the back of photos in pencil, and only lightly. Handle photos and negatives with gloves, or at least by the edges, because fingerprints stay on them permanently.

A digital letter to the future: an email that arrives on its own

There are services that send an email to yourself or someone else on a set date in the future; the best known is FutureMe. Writing a letter like that takes ten minutes and costs nothing. But it has two weak spots to keep in mind: the inbox it's addressed to has to survive (a work email or an internet provider's address won't survive anything), and the service itself has to survive. For a five-year horizon it's a nice idea; for an eighteen-year one, paper is more reliable.

The digital part of the capsule deserves the same rule that both the National Archives and the Library of Congress recommend for family archives: three copies, on two different types of media, one outside the house. A flash drive sealed in a box doesn't meet this rule even once, because it's a single copy on a single medium in a single place. Whatever digital items you put in the capsule, keep the main copy outside it, in a folder you use and back up regularly, and name the files so they make sense without you: date, name, event.

What keeps being read after the capsule is opened

A capsule gets opened once. Much of what's inside is used up at that moment: the ticket gets read, the family has a laugh, and it goes in the trash. But a few things survive the opening, and the family keeps using them. Those are the ones worth reaching for when you want the capsule to be a gift, not just a moment.

Three work best: the letter (it gets read again and again, especially by children whose letter was written by someone who's no longer here), printed photos with captions, and something engraved with a date, like jewelry with a name and date or another keepsake gift that can be worn or set on a shelf.

A fourth option is a book. A personalized book with your child as the hero has a blank page for a dedication at the beginning, and that's a letter to the future with a cover and a spine: your child will read it on their own once they can read, and the book stays with them on the shelf instead of in a box. You can write the dedication in one evening, the digital version of the book is usually ready within 15 minutes, and the story has 12 illustrated spreads. If you're unsure about the wording, common mistakes and texts to borrow are in our article on what to write in a dedication; in both cases the same rule applies as for a letter in a time capsule — a specific date and one real memory beat a generic wish.

Sources

National Archives (USA): Storing Family Papers and Photographs — Recommended storage conditions for family papers and photos — temperature, relative humidity, acid-free enclosures, and why to avoid basements, garages, and attics.
National Archives (USA): Digitizing Family Papers and Photographs — The rule of three copies on two types of media with one kept outside the home, file naming, and why to keep the originals even after scanning.
Library of Congress: Personal Digital Archiving — How to care for digital photos, emails, and recordings so they can still be opened years later.
FutureMe — A service that sends an email to your future self on a set date; an example of what the digital version of a letter looks like.