Skip to content
calculatorzone
Updated for 20258 tools reviewed

The business calculators every founder bookmarks.

Eight tools we’ve seen used by founders, contractors and finance leads alike — from quick VAT maths to weighing IR35 implications.

Running a business means making financial decisions every day. From setting the right price to knowing when you’ll break even, the right calculator saves time and prevents costly errors.

We tested each calculator below for accuracy, speed, and relevance to UK businesses of all sizes — sole traders to small Ltd companies.

Our picks for 2025

  1. Editor’s pick
    01

    Editor’s pick

    Profit Margin Calculator

    Calculate gross, operating and net profit margins. Enter revenue and costs to see where money goes.

    Gross & net margin
    Revenue & cost analysis
    Percentage & amount
    Pricing decisions

    Best for: Business owners, managers and entrepreneurs pricing products or services.

    Try Profit Margin Calculator
  2. 02

    Runner-up

    Break-Even Calculator

    Find how many units to sell or revenue needed to cover costs. Essential for product launches and business plans.

    Units to break even
    Revenue target
    Fixed & variable costs
    Visual break-even chart

    Best for: Startups planning launches and businesses assessing new products.

    Try Break-Even Calculator
  3. 03

    Highly rated

    VAT Calculator

    Add or remove VAT from any amount instantly. Supports standard and reduced rates.

    Add or remove VAT
    Standard & reduced rates
    Net & gross breakdowns
    Batch calculations

    Best for: Business owners, accountants, and anyone calculating VAT-inclusive or exclusive prices.

    Try VAT Calculator
  4. 04

    Pick 4

    Invoice Totals Calculator

    Calculate invoice totals with multiple line items, quantities, rates and VAT.

    Multiple line items
    Quantity & rate inputs
    VAT per item
    Subtotal & total summary

    Best for: Freelancers and small business owners issuing invoices.

    Try Invoice Totals Calculator
  5. 05

    Pick 5

    Hourly Rate Calculator

    Calculate the hourly rate you need to charge to meet income goals. Factors working hours, holidays, expenses and tax.

    Target income based
    Holiday & sick allowance
    Expense factoring
    Day rate output

    Best for: Freelancers setting rates and contractors negotiating day rates.

    Try Hourly Rate Calculator
  6. 06

    Pick 6

    Markup Calculator

    Calculate the selling price based on cost and desired markup percentage. Converts between markup and margin.

    Cost to selling price
    Markup ↔ margin conversion
    Percentage & amount
    Reverse calculation

    Best for: Retailers and wholesalers using cost-plus pricing.

    Try Markup Calculator
  7. 07

    Pick 7

    IR35 Calculator

    Compare take-home pay inside vs outside IR35. Shows the financial impact of contract status.

    Inside vs outside compare
    Take-home pay
    Tax & NI breakdowns
    Dividend vs salary

    Best for: IT contractors and consultants working through limited companies.

    Try IR35 Calculator
  8. 08

    Pick 8

    Employee Cost Calculator

    Calculate the true cost of employing someone — employer NI, pension, and overheads included.

    Employer NI
    Pension contributions
    Total cost per employee
    Annual & monthly breakdown

    Best for: Business owners hiring and HR teams budgeting headcount.

    Try Employee Cost Calculator

Five business finance habits worth keeping

  • Know your margins: Track both gross and net profit margins monthly to spot trends early.

  • Price with confidence: Use the markup calculator to ensure every product covers costs and delivers profit.

  • Plan for VAT: Set aside VAT as you earn it rather than scrambling at quarter end.

  • Budget for true employee costs: Always factor NI and pension when planning hires.

  • Review rates regularly: Freelancers should recalculate their hourly rate at least annually.

Frequently asked

Healthy profit margins vary significantly by industry. Service businesses typically aim for 15-30% net margin, while retail may be 2-10%. Use the profit margin calculator to understand current margins and set realistic targets for your sector.

Use arrow keys to navigate items, Enter or Space to expand/collapse.

Browse the full business calculators index

Every calculator in this category, sorted alphabetically.

See all business calculators