How Ganakam calculates
Our approach
We believe a calculator is only as trustworthy as the logic behind it, so we publish exactly how each tool works. The rules below reflect the latest official provisions; the underlying calculation engine is the single source of truth for every tool on the site.
Primary sources: the Income Tax Department (incometax.gov.in), the Union Budget 2025 announcements, the Reserve Bank of India, and the official rules of each savings scheme. Last reviewed: June 18, 2026.
Income tax - new regime (FY 2025-26 / AY 2026-27, default)
Slabs applied to taxable income: nil up to ₹4,00,000; 5% from ₹4-8 lakh; 10% from ₹8-12 lakh; 15% from ₹12-16 lakh; 20% from ₹16-20 lakh; 25% from ₹20-24 lakh; 30% above ₹24 lakh. Salaried taxpayers get a standard deduction of ₹75,000. A Section 87A rebate (up to ₹60,000) makes taxable income up to ₹12,00,000 effectively tax-free, which extends to ₹12.75 lakh of salary after the standard deduction. Where income is just above ₹12 lakh, marginal relief caps the tax so it does not exceed the income over ₹12 lakh. A 4% health and education cess applies on the tax, and surcharge applies at higher income levels (capped at 25% under this regime).
Income tax - old regime (FY 2025-26)
Slabs: nil up to ₹2,50,000; 5% from ₹2.5-5 lakh; 20% from ₹5-10 lakh; 30% above ₹10 lakh. Salaried taxpayers get a ₹50,000 standard deduction. A Section 87A rebate of ₹12,500 applies if taxable income is up to ₹5,00,000. This regime lets you claim deductions such as Section 80C (up to ₹1.5 lakh), 80D, HRA exemption, and home-loan interest (up to ₹2 lakh on a self-occupied property), which our calculator subtracts before applying the slabs. A 4% cess applies.
HRA exemption (old regime only)
The exempt portion is the least of: actual HRA received; rent paid minus 10% of (basic + DA); and 50% of (basic + DA) for metro cities (Delhi, Mumbai, Kolkata, Chennai) or 40% for non-metro cities. HRA exemption is available only under the old regime.
Take-home (in-hand) salary
In-hand pay = gross salary − employee provident fund (12% of basic) − income tax − professional tax. We derive gross from your CTC by removing the employer PF contribution (12% of basic) and gratuity (about 4.81% of basic). Professional tax is state-specific; we use a standard monthly figure you can adjust. These are modelling assumptions and your actual payslip may differ.
SIP and step-up SIP
Future value assumes monthly compounding with each contribution made at the start of the month, using the standard SIP formula. A step-up SIP increases the monthly amount by your chosen percentage each year. The expected return you enter is an assumption used for illustration; actual market-linked returns are not guaranteed and will vary.
EMI
We use the standard reducing-balance formula:
EMI = P × r × (1 + r)n ÷ ((1 + r)n− 1)
Where P is the principal, r is the monthly interest rate, and n is the number of monthly instalments.
A note on accuracy
We take care to keep these calculations correct and current, and we update them when the rules change. Even so, the results are estimates for general information. If you spot an error, please tell us at contact@ganakam.in.