Urn Size Guide: What Size Cremation Urn Do I Need?
What size cremation urn do I need?
The simple rule: for every 1 pound a person or pet weighed in healthy life, you need about 1 cubic inch of urn space. So a 180 lb adult needs roughly 180 cubic inches, and a standard adult urn holds 200 cubic inches — enough for almost any adult up to about 200 lbs. If you're unsure, size up: a little extra room never hurts.
That one rule answers most questions. The chart and sections below cover the exceptions — children, infants, pets, sharing ashes, and choosing a companion urn for two.
Urn size chart
| Urn size | Capacity (cubic inches) | Best for |
|---|---|---|
| Keepsake | 3–5 cu in | A small portion of ashes — for sharing among family or displaying alongside a main urn |
| Small / youth | ~70 cu in | A child, or a small adult/pet up to ~70 lbs |
| Medium | ~120 cu in | A teen or smaller adult up to ~120 lbs |
| Standard adult (large) | 200–220 cu in | Most adults, up to ~200–220 lbs |
| Companion | 400+ cu in | Two people's ashes together |
| Infant | Varies (small) | Infant or stillborn loss — choose by guidance, not weight |
CustomUrns sizing: Our large urns stand about 10 inches tall and hold 200–220 cubic inches, suitable for the vast majority of adult cremations. Our 3-inch keepsakes hold 2–3 tablespoons of ashes — ideal for sharing.
How to calculate the size you need
- Take their healthy adult weight in pounds. (Use weight before any final illness.)
- Match it to cubic inches, 1:1. 150 lbs ≈ 150 cubic inches.
- Round up to the next urn size. For 150 lbs, choose a 200 cu in standard adult urn.
If you don't know the exact weight, a standard 200 cubic inch adult urn fits almost everyone. Crematoriums also size this way, so it's the safe default.
Choosing a size for a child or infant
For a child, use the same 1 lb = 1 cubic inch rule with their weight. For an infant or stillborn baby, weight-based math doesn't apply the same way — these are deeply personal choices, and small, tender designs are made specifically for this purpose. Our baby & infant urns are sized and designed with this in mind, and we're glad to help you choose gently.
Choosing a size for a pet
Pets follow the same rule: about 1 cubic inch per pound of your pet's healthy weight. A 40 lb dog needs roughly 40 cubic inches; a cat usually needs far less. Many families also choose a keepsake to hold a small portion. Browse our pet cremation urns, many available with matching keepsakes.
Sharing ashes among family (keepsakes)
If several family members each want to keep a portion, keepsake urns are the answer. Our 3-inch keepsakes hold 2–3 tablespoons each, and several designs come bundled with 1, 2, or 4 matching keepsakes so everyone can hold a piece of the memory. The main urn still holds the majority of the ashes.
Will I be able to bury or display the urn?
All our urns suit home display, columbarium placement, or cemetery burial. If you plan to bury the urn, confirm any urn-vault requirements with your chosen cemetery first, as these vary by location.
Still not sure? We're here to help
Choosing an urn shouldn't add stress to a hard time. If you'd like help picking the right size or design, contact us — we'll guide you with care. Every CustomUrns piece is handcrafted, and most can be personalised with a name, dates, or a short message.