Repotting Pot Size Calculator
Find the right next pot size so you upsize without drowning the roots.
Repot in spring or early summer when the plant is actively growing, and water it in well afterwards.
Don't over-pot your plant
The most common repotting mistake is jumping to a pot that's far too big "so it has room to grow." The opposite happens: the extra soil holds water the small rootball can't drink, stays wet, and rots the roots. The rule is simple: go up one size at a time.
How this works
It adds one standard size step to your current diameter (a little more for fast growers), then estimates the extra soil volume the new pot will need so you can buy the right amount.
Frequently Asked Questions
How big should the next pot be?
Go up just one size: about 2.5 cm (1 inch) wider for pots under 20 cm, and about 5 cm (2 inches) wider for larger pots. Jumping several sizes surrounds the roots with wet, unused soil that stays soggy and invites root rot.
When does a plant actually need repotting?
Signs include roots circling the bottom or poking out of drainage holes, water running straight through, soil drying out very fast, or stalled growth. Most houseplants are happy being repotted every 1-3 years.
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