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What most people overlook: after many years, your old purchase price can drop out of the calculation entirely.
| Rule | Figure | Law |
|---|---|---|
| Tax rate in year 1 of ownership | 40 % | § 109(a) |
| Tax rate after 25 full years of ownership | 5 % | § 109(aa) |
| Flat-rate amount in year 11 of ownership | 80 % of the sale price | § 105(1) |
| Flat-rate amount after 25 full years of ownership | 65 % of the sale price | § 105(1) |
| Replacement purchase before / after the sale | 2 years / 3 years | § 98(1) |
| Tax multiplier and surcharges | none | § 2(4) |
Formula · § 109 Aargau Tax Act
How is property gains tax calculated in the Canton of Aargau?
In the Canton of Aargau, property gains tax is your gain times the rate. Only your holding period (Besitzdauer), your years of ownership, sets the rate. Gain means sale price minus acquisition costs (Anlagekosten): what the house cost you. The rate falls from 40 % in year one to 5 % after 25 full years.
Nothing is added: no municipal multiplier, no surcharges (§§ 2 and 109 Aargau Tax Act, as of January 20251). Only time counts, not the size of the gain. In Zurich the rate rises with the gain, as the Zurich property gains tax calculator shows. If you inherited, your parents' purchase price and years usually count; see selling an inherited house.
What this means for you: each full year lowers the rate by 2 points, after ten years by 1. The clock runs from notarisation (Beurkundung) to notarisation, the signing before a notary. The anniversary already counts as a full year (information sheet 10.12). For your parents' house, the purchase date is in their old contract.
You know your rate once the purchase and sale dates are fixed. One figure is still missing, and everything depends on it: your sale price. The valuation gives it as a range, justified in writing, and works it through to what you keep.
Acquisition costs · § 105 Aargau Tax Act
Aargau property gains tax: which costs count, and when does the flat-rate amount apply?
For property gains tax, Aargau counts the purchase price, value-adding investments and buying and selling costs; beyond ten full years, at least a flat-rate amount. An extension adds value and counts; repainting does not. Buying and selling costs include notary fees, the usual estate agent's commission and advertising (§ 45 Tax Ordinance3). The bank's charge also counts if the sale ends your fixed-rate mortgage early2.
The flat-rate amount (Pauschale) is a fixed share of the sale price. It is 80 % in year 11 and 65 % after 25 full years. Higher costs count only if fully documented. The flat-rate amount and receipts cannot be combined (§ 105 Tax Act, as of January 20251; information sheet 7.2.42).
What this means for you: in the first ten years, every receipt counts fully. After that, the calculator takes the higher of the two. If the flat-rate amount applies, your old purchase price no longer matters. In the Cantonal Tax Office's official example (Kantonales Steueramt), it exceeded all receipts by CHF 30,600.
Worked example
Official example: detached house after 15 years.
The Cantonal Tax Office (Kantonales Steueramt) works through this case in its information sheet (sale in 2013). The tax scale and the flat-rate amount still apply unchanged today: the scale since 2001, the flat-rate amount since 2007. We recalculated the case from the law and reached the same result.
- Holding period 4 March 1998 to 4 March 2013
- 15 full years, so year 16 of ownership
- Acquisition costs with receipts: purchase price 390,000 + notary 2,400 + agent's commission 12,000
- CHF 404,400
- Flat-rate amount in year 16: 75 % of the CHF 580,000 sale price (§ 105)
- CHF 435,000
- Property gain: 580,000 − 435,000 (the higher amount counts)
- CHF 145,000
- Tax rate in year 16 of ownership (§ 109(q))
- 15 %
- Property gains tax: 145,000 × 15 %
- CHF 21,750
Deferral · § 98 Aargau Tax Act
When does a replacement purchase defer property gains tax in Aargau?
A replacement purchase (Ersatzbeschaffung) defers Aargau property gains tax if you sell your home and buy another. Both must be your permanent and exclusive home. Buying or building must fall within 2 years before or 3 years after the sale (§ 98 Tax Act1). The new home may be anywhere in Switzerland, not abroad.
Buying for less defers at most part of the tax. Full deferral needs a new home costing at least your sale price. In official example 10.2, a flat sells for CHF 520,000 with an 86,000 gain; the new one costs 460,000. Only 26,000 stays deferred; 60,000 is taxed at 28 % in year 7: CHF 16,8002.
What this means for you: deferred is not waived; a later sale without replacement taxes this gain too. With the new home's price, the calculator shows what remains taxable. The municipality (Gemeinde) usually bills first, ignoring the replacement purchase. Submit proof within 3 years of the sale (form 112.01, as of 20264).
To be honest
When does waiting work out better in Aargau?
CHF 116,600 in tax on a 530,000 gain, or 22 %: the cost of selling after nine full years (our calculation, § 109 Tax Act). One year later the rate is 20 %, and the flat-rate amount can count for the first time. Until then, the rate falls by 2 percentage points with each full year. If nothing forces you to sell, waiting during these years works out better for tax.
After 25 full years it is the reverse: rate and flat-rate amount stay at 5 % and 65 %, however long you wait. Then what counts is whether selling, moving or staying fits your life; the home check in six questions helps you sort that out. The valuation with net calculation shows in writing which path adds up: sell, wait or keep. It remains free of charge, even if the answer is «keep».
Aargau property gains tax: what do owners ask most often?
Is there a tax-free allowance for property gains tax in Aargau?
No. In Aargau every franc of gain is taxable; there is neither an allowance nor an exemption threshold. In the first year of ownership the rate is 40 % (§ 109 Aargau Tax Act). A gain of CHF 12,000 therefore means CHF 4,800 in tax.
Does maintenance count for property gains tax in Aargau?
No. Maintenance such as repainting or a repair never counts, not even retrospectively. It is deductible for income tax, so the law excludes it from property gains tax (§ 104(2) Tax Act; information sheet 7.2.2). Value-adding investments such as an extension, by contrast, lower the gain if you document them.
What does the 3 % security mean in Aargau?
3 % of the price your buyer pays: up to this amount, a statutory lien (gesetzliches Grundpfandrecht) on the property secures the tax. It needs no entry in the land register (Grundbuch), the official record of who owns land, and is no extra tax. It lapses if other security is provided. One way is to pay 3 % to the office that collects the tax (§ 234a Tax Act; information sheet, section 9).
Does each Aargau municipality calculate property gains tax differently?
No. The rate is in the cantonal Tax Act and the same everywhere, with no tax multiplier or surcharge (§ 2(4) Aargau Tax Act). The tax commission (Steuerkommission) of the municipality where the house stands issues the assessment, not the one where you live (§ 164 Tax Act). The revenue goes half to the canton and half to the municipality (§ 111 Tax Act).
Is the property gains tax calculator for Aargau binding?
No, the calculator gives an estimate under the Aargau Tax Act, not a tax assessment. It works with your estimates and assumes a residential house with no earlier tax deferral. The assessment by the municipality where the house stands is decisive. Formula, official example and sources are on this page, so you can check the figures yourself.
Does the Aargau calculator save my entries?
No. Your figures stay in your browser; we do not see them. You do not need to log in.
Sources
- Aargau Tax Act (Steuergesetz des Kantons Aargau, SAR 651.100), §§ 2, 95–111, 164 and 234a, in German · version of 1 January 2025, accessed 29 September 2026
- Information sheet on property gains tax (Merkblatt Grundstückgewinnsteuer), Aargau Cantonal Tax Office, in German · amended 1 July 2023, accessed 29 September 2026
- Ordinance to the Aargau Tax Act (Verordnung zum Steuergesetz, SAR 651.111), §§ 44–46, in German · version of 1 January 2026, accessed 29 September 2026
- Form 112.01, tax return for property gains (Steuererklärung Grundstückgewinne), in German · as of 1 January 2026, accessed 29 September 2026
- Canton of Aargau: property gains tax (responsibility, rates), in German · published 1 July 2025, accessed 29 September 2026
General information, not individual advice. The law, the tax assessment and advice from professionals for your situation are what count.
