Real Estate Tax Calc
The 7 inputs every capital gains calculator needs
1. Original purchase price
The total amount you paid for the property at the time of acquisition, including the purchase price plus any closing costs you elected to add to basis (loan origination fees paid by buyer, title insurance, recording fees, transfer taxes paid by buyer). Do not include costs that were deducted in the year of purchase.
Where to find it: Your original closing disclosure (HUD-1 or Closing Disclosure form). If you bought decades ago, check your original purchase agreement and title settlement statement.
2. Capital improvements
The total of all qualifying capital improvements made during your ownership — costs that add value, extend useful life, or adapt the property. This is the cumulative total over the entire holding period, not just recent improvements.
Where to find it: Your property records folder with contractor invoices, permits, and receipts. If you have rental property, improvements also appear on Form 4562 or your depreciation schedule.
What to exclude: Routine repairs (painting, fixing leaky faucets, replacing broken fixtures) are not capital improvements and do not add to basis.
3. Total accumulated depreciation taken
This is the most commonly entered incorrectly. For rental property, you have been deducting MACRS depreciation every year on Schedule E and Form 4562. The total of all those deductions reduces your adjusted basis and creates the "depreciation recapture" layer taxed at up to 25%.
Where to find it: Sum of all depreciation deductions on past tax returns, Form 4562. Your CPA's depreciation schedule will show this as "accumulated depreciation." For residential rental at 27.5 years straight-line, the annual deduction is building value ÷ 27.5.
Critical warning: Even if you did not claim depreciation (some first-time landlords miss this), the IRS "allowed or allowable" rule under IRC §1016(a)(2) reduces your basis as if you had taken it. Entering $0 when you should have taken depreciation will give you a falsely low tax estimate and a surprise at filing time.
4. Sale price
The gross sale price as listed in your purchase and sale agreement and as it will appear on Form 1099-S. Do not subtract selling costs here — there is a separate field for that.
5. Selling costs
Direct costs of the sale that reduce your amount realized: real estate commission (typically 5–6%), title insurance (seller's portion), transfer taxes, attorney fees for the closing, recording fees, and any seller concessions that are a closing cost. Do not include costs of pre-sale improvements (those go in the improvements field).
Typical: 6–8% of sale price for commissions plus closing costs.
6. Taxable income estimate
Your estimated taxable income for the year of sale (including the gain). This determines which long-term capital gains rate bracket applies: 0%, 15%, or 20%. The calculator uses this to apply the correct federal long-term rate.
Where to find it: Estimate from your prior year Form 1040 Line 15 (taxable income), then adjust for expected changes and add your estimated gain.
7. Filing status
Single, Married Filing Jointly, Married Filing Separately, or Head of Household. This affects the income thresholds for the 0%, 15%, and 20% long-term capital gains brackets.
Common mistakes and how to avoid them
| Mistake | Effect | Fix |
|---|---|---|
| Entering $0 for depreciation on a rental | Overstates basis, understates tax | Pull depreciation from Form 4562 for each year owned |
| Using land value in depreciation base | Overstates depreciation, understates basis | Depreciate only the building value (exclude land) |
| Forgetting selling costs | Overstates amount realized, overstates gain | Include commission plus all closing costs paid by seller |
| Not tracking improvements over the years | Understates basis, overstates gain | Maintain a running log; review all years' records |
| Using purchase price instead of adjusted basis | Misses both improvements and depreciation | Calculate adjusted basis: purchase + improvements − depreciation |
| Not accounting for the §121 exclusion | Overstates tax on a primary residence sale | If it was your main home ≥2 of last 5 years, apply exclusion |
How to interpret calculator output
A good capital gains calculator will break your estimated federal tax into tiers:
- Tier 1 — Unrecaptured §1250 gain: This is the depreciation recapture portion, taxed at your federal long-term rate capped at 25%. You can't avoid this through timing or income planning — it follows the depreciation you took.
- Tier 2 — §1231 long-term capital gain: Gain above the recapture amount. This is where rate planning (timing the sale to a lower-income year) can save money.
- Tier 3 — NIIT estimate: The 3.8% surtax, if applicable. This is not always shown as a separate tier in every calculator but should be.
- Total estimated federal tax: Sum of tiers. Does not include state capital gains tax.
Worked example using the calculator
Inputs:
- Original purchase price: $260,000
- Capital improvements: $35,000
- Accumulated depreciation: $78,545 (8.5 years at $260K building value / 27.5)
- Sale price: $480,000
- Selling costs: $28,800 (6%)
- Filing status: Single, estimated taxable income $95,000 (includes this gain)
Calculator steps:
- Adjusted basis: $260,000 + $35,000 − $78,545 = $216,455
- Amount realized: $480,000 − $28,800 = $451,200
- Total gain: $451,200 − $216,455 = $234,745
- Tier 1: $78,545 × 25% = $19,636
- Tier 2: ($234,745 − $78,545) = $156,200 × 15% = $23,430
- NIIT: Assume $95K income with gain pushes above $200K threshold by ~$34,745; NIIT ≈ $34,745 × 3.8% = $1,320
- Total estimated federal tax: ~$44,386
What the calculator cannot do
A calculator is a planning tool, not a tax return. It cannot capture:
- Prior-year §1231 losses that may recapture current year §1231 gains as ordinary income
- Passive activity rules that may limit or release suspended passive losses on rental property sale
- State capital gains tax (varies dramatically by state)
- Your actual income for the year, which determines the exact LT CG rate bracket
- Complex situations: installment sales, partial §121 exclusion, OZ deferral, or 1031 basis carryover
For these situations, use a tax professional or comprehensive tax software (TurboTax, H&R Block, ProSeries, Drake) to file the actual return.
Frequently asked questions
What numbers do I need for a capital gains calculator?
You need: (1) original purchase price, (2) purchase closing costs you added to basis, (3) total capital improvements made during ownership, (4) total MACRS depreciation taken (from your tax returns or Form 4562), (5) sale price, (6) selling costs (commissions, closing fees), and (7) your estimated taxable income for the sale year (to determine which LT CG rate bracket applies).
Where do I find my depreciation amount for the calculator?
Your total accumulated depreciation is on your prior-year tax returns. Look at Form 4562 (Depreciation and Amortization) for each year you owned the property and sum the depreciation deductions taken. Alternatively, your CPA may maintain a depreciation schedule. If you never deducted depreciation, the IRS 'allowed or allowable' rule (IRC §1016(a)(2)) means you may still be treated as if you took it — the depreciation is subtracted from your basis regardless.
Is a capital gains calculator result accurate for tax filing?
A calculator gives an educational estimate, not a tax filing figure. The actual tax depends on your complete tax situation: other income, prior §1231 losses, passive activity rules, state tax, installment sale election, §121 exclusion eligibility, and other factors only a complete return can capture. Use calculator results for planning; use a tax professional or tax software for filing.
What is the biggest mistake people make when using a capital gains calculator?
The most common mistake is entering $0 for depreciation when they actually took depreciation deductions on their rental property. Under the 'allowed or allowable' rule, the IRS requires you to reduce your basis by depreciation you could have taken — even if you didn't actually claim it. Entering $0 depreciation will overstate your adjusted basis and understate your tax by potentially tens of thousands of dollars.
Does the calculator include state capital gains tax?
Our Capital Gains Tax Calculator at realestatetaxcalc.com covers federal tax only. State capital gains tax rates and rules vary significantly. Most states that have an income tax also tax capital gains as ordinary income (rates from ~3% to over 13%). A few states (Florida, Texas, Washington on most income, Nevada, Wyoming, South Dakota, Alaska) have no state income tax.
Educational information and estimates only. Not tax advice. Tax rules change and vary by situation; consult a qualified tax professional before acting.