GROWING TOOLS
Repot Size Calculator: The Next Pot
The next pot is only 1 to 2 inches wider than the pot the roots already fill. The Royal Horticultural Society calls a much larger jump overpotting. Under 10 inches, choose about 1 to 2 inches wider and not much deeper. A 10-inch pot can stay that size if you trim roots.
Choose the inner diameter of the pot the plant is in now. The result is the next diameter. Find roots at the drainage hole before you move the plant.
Example next pot
5 to 6 inches. Next pot: 5 to 6 inches wide, and not much deeper. Do not jump from 4 inches past 6. Move the plant only if roots are already crowded at the drainage hole.
The example starts at 4 inches. Change the menu to match the pot you have.
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How wide is one step up?
| Current pot | Next pot | Also consider |
|---|---|---|
| 2 in. | 3–4 in. | Do not skip to a pot past this step. |
| 3 in. | 4–5 in. | Do not skip to a pot past this step. |
| 4 in. | 5–6 in. | Do not skip to a pot past this step. |
| 5 in. | 6–7 in. | Do not skip to a pot past this step. |
| 6 in. | 7–8 in. | Do not skip to a pot past this step. |
| 8 in. | 9–10 in. | Do not skip to a pot past this step. |
| 10 in. | 11–12 in. | Same pot plus a root trim is reasonable. |
| 12 in. | 13–14 in. | Same pot plus a root trim is reasonable. |
Drainage and mix are the other half: drainage holes and indoor plant care. If the mix stays wet after a move, use root rot before you water on the old schedule. Set the next check with the watering calculator. A pothos that has filled a 4- to 6-inch nursery pot is pothos care. A Mexican butterwort does not use this step blindly: butterwort care.
How it decides
Bands, limits, and the sources behind them
The Royal Horticultural Society’s overpotting note says to move into a pot about 2.5 to 5 centimeters, or 1 to 2 inches, wider than the previous one, and not much deeper. A much larger pot leaves a ring of mix that stays wet, and roots can rot instead of growing out. Its repotting guide repeats the same 1 to 2 inch step for containers under about 10 inches, and it says the new pot should be no more than about one third larger. At that size and above, many plants can stay put if you trim a modest amount of root and refresh the mix. Illinois Extension’s houseplant notes still start with a pot that drains and a mix that is not garden soil. This calculator returns the next diameter only. It does not name a brand of mix, and it does not tell you to repot a plant whose roots have not filled the pot.
Common questions
Should I repot if the plant looks fine?+
Only when roots are crowded at the drainage hole or the mix has collapsed. A plant that is still rooting into open mix does not need a larger pot this season.
Why not jump two pot sizes?+
The Royal Horticultural Society says the spare mix stays wet and roots can rot. One to two inches of extra diameter is the step. Deeper “long tom” pots are a separate risk.
What about a 10-inch or 12-inch pot?+
You may move up 1 to 2 inches, or keep the same pot, trim a modest share of the roots, and refresh the mix. Do not jump from 12 inches to a tub.
Does a butterwort use this same step?+
No. Mexican butterworts often stay in a small pot and are repotted in the succulent phase, not sized up like a pothos. Use the butterwort page before you change that pot.
Sources and notes
The result is a diameter step, not a brand of potting mix. Sources checked November 6, 2026. Editorial responsibility.