All English calculators

15 tools for practical decisions, each with visible inputs, a formula and a worked example.

• Profit Margin Calculator

  Find profit, profit margin and markup from revenue and costs. Compare the two percentages before setting a selling price.

• Markup Calculator

  Set a selling price from your cost and chosen markup. See the resulting profit margin alongside the price.

• Break-even Calculator

  Estimate the sales quantity needed to cover fixed and variable costs. Check each sale's contribution before planning a target.

• ROI Calculator

  Compare the total amount returned with your investment. Calculate net gain or loss and simple return on investment.

• Freelance Hourly Rate Calculator

  Build an hourly billing target around income, overhead and realistic billable hours. Allow for profit without treating every working hour as paid work.

• Flooring Cost Calculator

  Estimate flooring materials and installation for a rectangular room. Keep the material area you buy separate from the floor area being installed.

• Paint Calculator

  Estimate paint for four walls, allowing for openings, coats and waste. Enter the coverage specified for your chosen product.

• Tile Calculator

  Estimate the number and cost of tiles for a rectangular floor. Add a cutting allowance, then round up to individual whole tiles.

• Concrete Calculator

  Find the concrete volume and assumed material cost for a rectangular slab. Add an allowance without changing the measured dimensions.

• Room Area Calculator

  Find the floor area and perimeter of a rectangular room. Use the measurements as a starting point for flooring, tile or paint estimates.

• Fuel Cost Calculator

  Estimate trip fuel and cost from distance, consumption and your fuel price. Switch explicitly between litres and US or UK gallons.

• Road Trip Cost Calculator

  Build a road trip budget with fuel, tolls, parking and accommodation. Compare the whole-trip cost with each traveller's share.

• EV Charging Cost Calculator

  Estimate energy drawn from the charger and the cost of an electric-car trip. Keep charging losses separate from driving consumption.

• Percentage Calculator

  Calculate a percentage of an amount, including zero and negative values. See the multiplication behind the result.

• Discount Calculator

  Find the sale price and savings from a single percentage discount. Check the reduction before comparing an offer.