A useful room budget gives every known cost a line.
This calculator turns one room-project limit into category ceilings. It is intentionally narrower than a household budget: you choose the amount available and the category shares, while RoomFact performs the arithmetic and shows whether the allocation accounts for exactly 100%. The result does not decide what you can afford, recommend borrowing, or claim that one percentage split suits every room.
The extra purchase-cost category is deliberate. Product prices are not always the amount paid after tax, shipping, delivery, assembly, installation, or disposal. Those predictable costs should be visible before a furniture allowance is spent. Contingency is kept separate for changes that were not already listed, so the same reserve is not quietly promised to known charges and unexpected problems at the same time.
Worked example
A $10,000 room plan with all costs assigned
A shopper has already chosen a $10,000 USD limit for one room. The loaded example is adjusted to match the actual scope before any order is placed.
Total limit
$10,000 USD
Furniture
50% / $5,000
Lighting
10% / $1,000
Finishing and decor
15% / $1,500
Tax, delivery, and setup
10% / $1,000
Contingency
15% / $1,500
How RoomFact reads it
The five shares total 100%, so the calculator assigns the complete $10,000. It reports category ceilings of $5,000, $1,000, $1,500, $1,000, and $1,500; it does not suggest that every ceiling should be spent.
The $5,000 furniture amount is a decision boundary. Spending less can leave room for another category or reduce the project total; it is not a target to exhaust.
The $1,000 purchase-cost amount is only a placeholder until seller and installer quotes reveal the actual tax, delivery, assembly, installation, or disposal cost.
The $1,500 contingency remains uncommitted. A known delivery charge belongs under purchase costs even if moving it there requires changing both percentages.
01
Start with the complete project limit
Choose the room limit outside this calculator, using your wider financial situation and obligations. Entering a larger number does not make the purchase affordable, and RoomFact does not calculate income, debt, interest, credit fees, or emergency savings. If the project depends on borrowing or competes with essential expenses, use a broader personal budget and appropriate financial guidance before treating this result as a shopping limit.
Keep every entry in one currency. The selector changes the symbols and codes used in the result; it does not look up exchange rates. If products are priced in another currency, convert those quotes separately and include card, conversion, duty, or import costs that apply to your purchase before comparing them with a category ceiling.
02
Separate product prices from purchase costs
Build the estimate from the amount that could actually leave your account. Alongside product prices, check tax, shipping, handling, room-of-choice delivery, assembly, installation, old-item removal, disposal, permits, and trade work. Some costs belong naturally with a product category; the purchase-cost bucket exists for cross-project charges that would otherwise disappear between a product page and checkout.
Do not place a cost in contingency merely because its exact quote is not ready. Use a current estimate, mark it as provisional, and replace it when the seller or contractor confirms the amount. Contingency is more useful when it remains available for a genuinely unlisted change, damaged surface, replacement part, or scope decision instead of paying a charge that was predictable from the start.
03
Replace the example percentages with your room
There is no universal ideal split between furniture, lighting, finishing, purchase costs, and contingency. A room that already has useful lighting may assign almost nothing there. A remote delivery, built-in installation, or several second-hand purchases can create a completely different cost structure. The loaded 50/10/15/10/15 split demonstrates the calculation only; it is not a benchmark drawn from household spending data.
For each category, the formula is total project limit multiplied by the entered share and divided by 100. If the shares are below 100%, the result names the money that remains unassigned. If they exceed 100%, it names the amount allocated more than once. Resolve that difference before comparing products so two categories are not relying on the same dollars.
04
Track planned, committed, and paid separately
A category ceiling is only the plan. Record a product as committed when an accepted order, signed quote, or non-refundable deposit obligates the money, even if the final payment happens later. Record it as paid when the charge clears. Keeping those states separate prevents an unpaid balance from looking available and prevents one purchase from being counted in both an order list and a card statement.
Save receipts and compare actual costs with the plan as the room progresses. When one category changes, revise the remaining shares rather than rewriting the original purchase price. RoomFact's downloadable workbook includes Room Budget, Purchases, and Contingency sheets so the calculator's ceilings can become a simple ledger without creating an account or sending the entries back to the site.