---
title: "CIS tax month and deadlines"
method: POST
path: "/api/v1/tax-month"
tags: ["CIS"]
---

# CIS tax month and deadlines

`POST /api/v1/tax-month`

## Request

- Base URL: `https://0sand1s.co.uk`
- URL: `https://0sand1s.co.uk/api/v1/tax-month`
- Auth: none declared

For a date, gives the CIS tax month it falls in (the 6th to the 5th), the tax year, the date the monthly return (CIS300) is due (the 19th, also the date for paying HMRC by any means other than electronically), and the date for paying HMRC electronically (the 22nd, moved back to the banking day before when the 22nd is a weekend or an England and Wales bank holiday). Bank holidays are known to bank_holidays_known_until; after that only weekends move the date. The same as the GET, with the input as a JSON body.

## Request body

- object
  - `date` string, required: Any date, such as a payment date or today, YYYY-MM-DD

## Response `200`

The answer

- ToolResponse
  - `tool` string, required
  - `result` object, required: The answer. Amounts are { pence, pounds } objects; dates are YYYY-MM-DD.
  - `summary` string, required: The answer in one line
  - `sources` object[], required
    - `title` string
    - `url` string, uri
  - `see_also` string, uri, required: The page on 0sand1s.co.uk that does the same sum or explains the rule

## Other responses

- `400`: Input that could not be used, with a message per field
- `429`: More than 60 requests in a minute from one address

---

[API](https://skmtc.dev/0sand1s/apis/0s-and-1s-cis-api.md) · [All operations](https://skmtc.dev/0sand1s/apis/0s-and-1s-cis-api/llms.txt) · [OpenAPI document](https://skmtc.dev/0sand1s/apis/0s-and-1s-cis-api/revisions/caf4279c7477?raw)