Contractor Day Rate, Umbrella and IR35 Take-Home Pay Calculator
Compare annualised contract income with simplified outside-IR35 and umbrella take-home scenarios.
What this calculator explains
An advertised assignment rate is not necessarily the worker’s gross salary. In an umbrella arrangement, assignment income can fund the umbrella margin and employer employment costs before gross taxable pay is calculated. The results show this bridge line by line so employer costs are not mistaken for deductions from an already-agreed employee salary.
The calculator does not decide whether an engagement is inside or outside IR35. It compares cash-flow scenarios after the user selects a status and links to HMRC guidance and the client’s status determination process.
How the estimate is calculated
- Multiply the rate by realistic billable days or hours and exclude VAT from income.
- Subtract the entered umbrella margin and modeled employment costs from the assignment value.
- Calculate gross taxable employment pay under the selected arrangement.
- Apply pension and holiday-pay treatment as explicitly configured.
- Calculate PAYE Income Tax, employee National Insurance and student-loan deductions.
- For an optional outside-IR35 company scenario, show assumptions separately and never present it as equivalent to umbrella payroll.
Formula
Umbrella taxable gross pay = assignment income excluding VAT − umbrella margin − employer employment costs − other agreed assignment costs
Worked example
A £500 day rate over 220 billable days produces £110,000 of assignment income excluding VAT. If the selected umbrella margin and modeled employer employment costs total £16,000, the amount available as gross taxable employment pay is £94,000 before employee pension, Income Tax, National Insurance and student-loan deductions. The result itemises the £16,000 rather than hiding it in a single adjustment.
Current rules and configuration notes
- The calculator compares user-selected inside-IR35, outside-IR35 and umbrella cash-flow scenarios; it does not determine employment status.
- In an umbrella scenario, assignment income excluding VAT is reduced by the umbrella margin and modeled employer employment costs before taxable gross pay is calculated.
- The 2026/27 standard employer National Insurance rate used in supported scenarios is 15% above the applicable threshold.
Update requirement: Tax, NI, pension and umbrella guidance require tax-year review. Legal status language must be reviewed whenever off-payroll rules change.
Included in the estimate
- Day, hour and assignment-value conversion
- Umbrella margin
- Employer-cost bridge to taxable gross pay
- PAYE, employee NI, pension and student-loan inputs
- Billable versus nonbillable days
- Clearly separated status scenarios
Not included or not guaranteed
- An IR35 status determination
- A review of contractual or working practices
- Guaranteed umbrella take-home pay
- Complete limited-company Corporation Tax and dividend planning
- Advice on a specific umbrella, agency or client
Frequently asked questions
What does inside IR35 mean?
The off-payroll rules aim to make a worker who would have been an employee pay broadly similar Income Tax and National Insurance when working through an intermediary.
Why is employer National Insurance shown in the umbrella calculation?
The assignment rate can be the umbrella’s income from the agency, from which employment costs are funded before gross employee pay. It is not described as a deduction from an already-stated employee salary.
Does VAT increase my take-home pay?
No. VAT collected on a taxable invoice is normally accounted for separately and is not treated as contractor income.
How many billable days should I use?
Start with working days and subtract holidays, gaps, sickness, training and other nonbillable time. A realistic annual figure is more useful than multiplying by every weekday.
Can this calculator prove I am outside IR35?
No. Status depends on the actual engagement, contract and working practices. Use the official process and obtain professional advice where needed.
Why do umbrella illustrations differ?
Margins, pension, holiday-pay presentation, tax code, student loans, pay periods and employment-cost assumptions can differ. Every selected setting is shown in the calculation.
Official sources
- GOV.UK — Understanding off-payroll working (IR35)
- GOV.UK — Working through an umbrella company
- GOV.UK — Income Tax rates and Personal Allowances
- GOV.UK — National Insurance rates and allowances
- GOV.UK — Workplace pension contributions
Applicable period: 2026-04-06/2027-04-05 · Last reviewed: September 3, 2026
Recommended internal links
Compare the whole assignment, not only the headline rate
Save umbrella and payroll scenarios with the same billable days so each illustration can be checked line by line.
CTA destination: /uk/contractors/ir35-take-home-pay-calculator/