Downsizing Space Calculator
Figure out what fits in your new smaller space, how many items to sell or donate, and if you need external storage.
About this calculator
This calculator uses the ratio between your new and current square footage as a proxy for how much of your stuff can realistically fit, then applies that ratio separately to furniture and storage items. The core number is the space ratio (new square footage divided by current), but furniture retention never drops below 40% of what you have now — the logic assumes a floor of "essential" pieces (a bed, a table, seating) survive any downsize regardless of how small the new place is, even if the raw ratio implies you'd need to shed more. Storage and miscellaneous items — boxes, seasonal gear, sports equipment — scale down more directly with the space ratio, without that 40% floor, since they're easier to compress, store off-site, or simply let go of than furniture. External storage need is estimated from what doesn't fit: furniture overflow at 15 square feet per piece (a rough stand-in for a storage-unit footprint) and item overflow at 5 square feet per box.
The percent-kept figure blends both furniture and storage retention into a single number, capped between 0 and 100. Keep in mind this is a rule-of-thumb space model, not a room-by-room plan — it can't know if your new place has an extra closet or your current furniture is unusually bulky. It's best used early in the downsizing process to set expectations (how much you'll realistically need to sell, donate, or store) before you get into itemized packing decisions.
Inputs
Results
Square Footage Reduction
800 sq ft
≈ 6 parking spaces
How to Use This Calculator
- Enter your Current Home Size and New Home Size in square feet.
- Set the number of Current Furniture Pieces and Storage/Misc Items you own.
- Review Square Footage Reduction, Furniture That Fits, and Items to Sell or Donate.
- Use the output to plan your decluttering process and identify items that will not fit in the new space.
How the result changes with Current Home Size
| Current Home Size | Square Footage Reduction |
|---|---|
| 900 | 0 sq ft |
| 1,350 | 350 sq ft |
| 2,700 | 1,700 sq ft |
| 4,500 | 3,500 sq ft |
What each input means
- Current Home Size
- Total square footage of your current home or apartment.
- New Home Size
- Total square footage of the home you're moving into.
- Current Furniture Pieces
- Count all major furniture: beds, sofas, tables, dressers, desks, bookshelves, etc.
- Storage/Misc Items
- Boxes, bins, seasonal items, sports equipment, and other stored belongings.
What each result means
- Square Footage Reduction
- How much smaller your new space is.
- Furniture That Fits
- Estimated number of furniture pieces that will fit in the new space.
- Items to Sell/Donate
- Furniture and storage items that won't fit and should be sold, donated, or discarded.
- External Storage Needed
- If you want to keep overflow items, this is the storage unit size needed.
- Percent of Items Kept
- Percentage of your current belongings that will fit in the new home.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersCurrent Home Size = 1800, New Home Size = 1000, Current Furniture Pieces = 20, Storage/Misc Items = 30 = 4 input(s) provided
- Calculate Square Footage ReductionSquare Footage Reduction = max(0800 = 800
- Calculate Furniture That FitsFurniture That Fits = max(011 = 11
- Calculate Items to Sell/DonateItems to Sell/Donate = max(022 = 22
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why doesn't furniture retention ever drop below 40%, even for a big downsize?
furnitureThatFits uses whichever is larger: the raw space ratio (new sq ft ÷ current sq ft) or a 40% floor. That floor exists because certain pieces — a bed, a table, essential seating — are assumed to survive any downsize regardless of how small the new place is. So going from 3,000 to 500 sq ft (a 17% ratio) still keeps 40% of your furniture pieces in the estimate, not 17%.
Why do storage and misc items scale down more than furniture does?
Storage items use the raw space ratio directly, with no floor, on the assumption that boxes, seasonal gear, and sports equipment are easier to compress, store off-site, or let go of than furniture is. So the same downsize that keeps 40% of your furniture pieces might only keep 20% of your storage items, if that's what the raw square-footage ratio works out to.
How is the external storage size figure calculated?
It sums two components: furniture pieces that don't fit in the new home are counted at 15 sq ft each (a rough stand-in for a storage-unit footprint), and storage/misc item overflow is counted at 5 sq ft each. Adding those together gives the total external storage square footage you'd need to keep everything the calculator estimates won't fit.
What exactly does "Percent of Items Kept" combine?
It blends furniture and storage retention into one number: (furniture that fits + storage items scaled by the space ratio) divided by your total original item count, capped between 0 and 100. Because furniture benefits from the 40% floor and storage items don't, this figure usually sits above the raw square-footage ratio alone.
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