For developers

A free API for Nepali salary tax

The same engine that runs the calculator on this site, over HTTP. No account, no API key, no rate card — just a POST with a salary in it.

What it is

A free JSON API that returns Nepali salary income tax — monthly TDS, take-home pay and a band-by-band breakdown — for fiscal years 2083/84, 2082/83, 2081/82. It is described by OpenAPI 3.1, needs no key, and stores nothing.

It runs the same tax module as this website, carried across byte for byte with its test suite, so an integration and the public calculator cannot quietly disagree. If a Finance Act changes a band, both move together.

Interactive docs OpenAPI 3.1 document

One request, start to finish

A salary of NPR 1,00,000 a month, on the Social Security Fund, with basic at 60% of gross:

curl -X POST https://api.salarytaxcalculatornepal.com/v1/calculate \
  -H 'content-type: application/json' \
  -d '{
    "monthlySalary": 100000,
    "basicSalaryMonthly": 60000,
    "scheme": "ssf"
  }'

Comes back with the annual tax (NPR 12,080), the monthly withholding (NPR 1,007), the take-home (NPR 92,393 a month), what each band took, and which relief was capped by which rule.

Endpoints

Method	Path	What it answers
POST	/v1/calculate	Annual and monthly tax on employment income, band by band, with every relief and the ceiling that capped it.
POST	/v1/calculate/across-years	The same person priced under every fiscal year in the registry.
POST	/v1/reverse	The gross salary that lands on a wanted monthly take-home.
POST	/v1/compare	Two offers scored against each other, including the fund balances built in your name.
GET	/v1/fiscal-years	Every fiscal year the API can price.
GET	/v1/fiscal-years/{id}	One year's full rate table — bands, relief ceilings and contribution rates.

Money on the wire

Amounts you send are rupees. Amounts you get back are integer paisa — NPR 1,234.56 comes back as 123456. Divide by 100 once, at the point you show it to someone.

Money is never a float in a response. 0.1 + 0.2 is not 0.3 in floating point, and a tax figure that drifts by a paisa a payslip is a reconciliation problem twelve months later. Rates come back as fractions: 0.01 is 1%.

What it implements

Assessable income is pay plus the employer's retirement contribution — that contribution is itself a taxable benefit.
Reliefs come off assessable income against their own ceilings, with PF/SSF and CIT sharing one ceiling of NPR 5,00,000 a year.
The bands run on what is left.
SSF members do not pay the 1% Social Security Tax band. Provident Fund members do.
A resident woman's computed tax gets a 10% rebate, applied last.

Fair use

Free, no key, no sign-up. There is a per-IP rate limit on the calculation routes to stop one impatient script monopolising it; normal use will never meet it. Nothing is stored — no account, no logging of the salaries you send.

What it is not

Not tax advice, and not a filing. It is an estimate accurate to the rules it implements, on the inputs you give it. Payroll may reach a different number for allowances, benefits in kind or arrangements this does not model — see the terms.

Prefer the tool?

The salary tax calculator runs the same engine in your browser, and the tax slabs page publishes the same tables as HTML.