Sources and assumptions

Last updated: 2026-08-18

Vicaya separates calculator math from real-world decisions. The site can model a scenario, but it cannot know every lender rule, employer benefit, local tax, insurance detail, or personal filing fact that may affect the real answer.

Mortgage and loan assumptions

Loan pages generally assume the rate and payment timing entered by the user. Fixed-rate repayment pages use amortization schedules. Taxes, insurance, HOA charges, points, closing costs, and extra payments are included only when the page asks for them and the user enters them.

Paycheck assumptions

Paycheck pages model federal withholding, FICA, deductions, and supported state or local coverage as an estimate. Employer-specific benefit rules, worker classification, local tax exceptions, garnishments, and payroll-provider settings may change a real paycheck.

Investment and retirement assumptions

Investment pages use the entered return, contribution pattern, time horizon, tax, fee, and inflation assumptions. They do not forecast markets and do not recommend any security, account, or allocation.

India salary and tax assumptions

India pages model cost to company, provident fund, gratuity accrual, professional tax, employee state insurance, house rent allowance exemption, and income tax deducted at source under both the new and old regimes. Rule data is confirmed against the Income Tax Department, the Ministry of Labour and Employment, EPFO, ESIC, and Article 276(2) of the Constitution for professional tax, which is levied by states rather than centrally.

Two limits are worth stating plainly. Professional tax schedules differ by state and change by notification; where a state's schedule has not been confirmed against that state's own notification, the result says so rather than assuming a figure. And the split of a package into basic pay, allowances, and benefits is set by an employer, not by statute, so a package of the same size can produce a different take-home figure at two employers. Where the split is not entered, it is estimated, and the page marks the result accordingly.

What the calculators do not model

No page models a lender's underwriting, a specific employer's benefit scheme, an individual's full tax position, arrears or retrospective adjustments, garnishments, equity compensation tax treatment beyond the fields provided, or any product available on the market. Where a calculation depends on something the page does not ask for, that figure is outside the estimate rather than silently assumed.

Currency and rounding

Amounts use the major unit of the selected currency and are displayed to that currency's minor unit. Indian figures are grouped in the lakh and crore convention. Internal precision is higher than the display, and a final schedule row may absorb a rounding difference so a balance reaches zero exactly.

How to read an estimate

Treat each result as a planning number. Use it to understand sensitivity and tradeoffs, then check final figures with official forms, statements, lenders, payroll providers, or licensed professionals. Where two scenarios are close together, the assumptions behind them matter more than the gap between them.

For payroll-specific entry points, open the paycheck tools hub the India salary and tax hub or the UK salary and tax hub. For broader planning, start from the calculator directory, and see calculation methodology for how the figures are derived.