How do you use the construction cost calculator?
- Enter the built-up area and the contractor’s quoted rate per sq ft.
- Add the architect’s and engineer’s fees, approvals and connections, a contingency, and the total for any work the quote leaves out.
- Read the cost to build. To list the extras one by one, or add a plot and interiors, open “Adjust rates, plot and itemised extras”.
Why does a house cost more than the per sq ft quote?
A contractor’s rate per sq ft rarely covers everything. Some quotes cover the structure only; others include basic electrical and plumbing but leave flooring, doors, windows, the kitchen and bathroom fittings to you. Then come design fees, the building plan approval, power and water connections, and changes you make once work starts. The only reliable way to budget is to get the scope of the quote in writing and add what is left out.
How the budget is worked out
Built-up area × quoted rate per sq ftQuote + work not in the quote + fees + approvalsSubtotal × (1 + contingency %)Cost to build + plot + stamp duty and registration on the plot + interiorsWorked example: 2,000 sq ft at ₹ 2,500 a sq ft
The quote is ₹ 50,00,000. Add ₹ 1 L for the architect and engineer, ₹ 50,000 for approvals and connections, and a 10% contingency of ₹ 5,15,000. The cost to build is ₹ 56,65,000, or ₹ 2,833 a sq ft, 13.3% above the quote.
Worked example: a structure-only quote
If the same quote leaves out electrical (₹ 1.5 L), plumbing (₹ 1.2 L), flooring (₹ 3 L), doors and windows (₹ 2 L) and the kitchen and bathrooms (₹ 2.5 L), the cost to build rises to ₹ 67,87,000, or ₹ 3,394 a sq ft, 35.7% above the quoted rate. Buying a ₹ 60 L plot as well adds ₹ 4,56,000 in stamp duty and registration.
What does the quote turn into?
| Built-up sq ft | Quoted rate | Cost to build | Per sq ft, all in |
|---|---|---|---|
| 1,200 | ₹ 2,000 | ₹ 28,05,000 | ₹ 2,338 |
| 1,200 | ₹ 2,500 | ₹ 34,65,000 | ₹ 2,888 |
| 2,000 | ₹ 2,000 | ₹ 45,65,000 | ₹ 2,283 |
| 2,000 | ₹ 2,500 | ₹ 56,65,000 | ₹ 2,833 |
| 3,000 | ₹ 2,500 | ₹ 84,15,000 | ₹ 2,805 |
| 3,000 | ₹ 3,000 | ₹ 1,00,65,000 | ₹ 3,355 |
What stamp duty applies if you buy the plot?
On a sale deed in Bengaluru, Karnataka charges 5% stamp duty on the market value (Karnataka Stamp Act, Schedule Art. 20(1)), a 10% cess on the duty (s.3B) and, inside the Greater Bengaluru Area, a 2% surcharge on the duty (Greater Bengaluru Governance Act 2024, s.170). The registration fee is 2% (IGR notification of 29 Aug 2025, in force from 31 Aug 2025). Together that is 7.6% of the value. The first sale of a flat pays less duty: 2% up to ₹ 20 L and 3% above ₹ 20 L up to ₹ 45 L, so the total is 4.24% or 5.36%. Resale flats, plots and houses pay 5% at any price. Rates verified 18 Oct 2026 · confirm on Kaveri Online before registering. Plots pay the standard 5% duty; the lower first-sale rates are for flats only.
What should you check before you sign with a contractor?
- Get the scope in writing: what the rate includes, the brands and grades of material, and what is excluded.
- Agree payment stages tied to finished work, not dates.
- Get the building plan approved before work starts, and have a property lawyer check the plot’s title and approvals.
Frequently asked questions
Related answers and guides
- Under-Construction Site Visit Checklist
- Home Loan for Under-Construction Flats
- Buying Under-Construction in Bengaluru: 20 Questions
- Villa Projects Bangalore: Approvals, UDS and Plot Checks
Sources
- Stamp duty 5% (Schedule Art. 20(1)), first-sale flat slabs (Art. 20(2A)) and 10% cess (s.3B): Karnataka Stamp Act 1957, consolidated copy (DPAL); ₹ 35–45 L slab: Karnataka Stamp (Amendment) Act 2021.
- 2% surcharge on duty in the Greater Bengaluru Area: Greater Bengaluru Governance Act 2024, s.170.
- Registration fee 2%: IGR Karnataka, Table of Registration Fees (Notification RD/46/MNMU/2025) and IGR press note, 29 Aug 2025.
- Rates verified 18 Oct 2026 · confirm on Kaveri Online before registering.
- Area, quoted rate, fees, extras, contingency, plot and interiors: your inputs. No construction rates are assumed.
Indicative figures from the numbers you enter, not a quote. For GST and tax, indicative only. For plot title and building approvals, please consult a property lawyer before acting.
Building on a plot in Bengaluru? Talk to an acre&key advisor.