0s and 1s CIS calculators

uk.co.0sand1s/cis · v1.0.1 · finance-and-payments

0s and 1s CIS calculators is healthy: it completed an MCP handshake in 715 ms and exposes 7 tools.

Free UK CIS calculators: deductions, deadlines, late penalties, gross payment test, verification.

Endpoint: https://0sand1s.co.uk/mcp (streamable-http)

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Tool count7
Latency715 ms
Last checked (UTC)2026-10-18T21:45:35.341Z

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2026-10-18T21:45:35.341ZHealthy715

Tools (7)

cis_deductionWorks out the CIS deduction on a payment to a subcontractor, from the gross bill to the net payment. Takes the gross including VAT, the VAT, the subcontractor's materials and the rate (0, 20 or 30). VAT is never taxed under CIS and materials come off before the rate applies; the deduction is rounded
cis_gross_upFinds the gross amount (excluding VAT) that leaves a given net payment after the CIS deduction, for a subcontractor quoted a take-home figure. Takes the net, the subcontractor's materials and the rate (0, 20 or 30). Where rounding lets two grosses give the same net, the larger is returned so CIS is
cis_tax_monthFor 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 befor
cis_late_penaltiesWorks out the late filing penalties on one monthly CIS return under Finance Act 2009 Schedule 55: £100 the day after the 19th, £200 at 2 months, then the greater of £300 and 5% of the deductions at 6 and at 12 months (5% alone for a first return). Takes the tax year and month, the filing date or non
cis_gross_payment_turnover_testChecks the turnover test for CIS gross payment status (Finance Act 2004 Schedule 11, SI 2005/2045 reg 28): £30,000 net construction turnover for a sole trader; for a partnership or company, the lower of £30,000 for each partner or relevant person and £100,000. In a close company, shareholders count
cis_needs_verificationSays whether a contractor must verify a subcontractor with HMRC before paying them (SI 2005/2045 reg 6): not needed if the subcontractor was on one of this contractor's CIS returns, or was verified by this contractor, in the tax year of the payment or the two before. Takes the payment date, the tax
cis_nil_return_checkSays whether a contractor must file a CIS nil return for a tax month (SI 2005/2045 reg 4(9A) and (9B), inserted by SI 2026/289 from 6 April 2026): due when a mainstream contractor that has paid subcontractors before pays none that month, unless it told HMRC no later than 14 days before the month sta