500 practical tools for money, accounting, maths, physics and everyday work. Compare costs, check a formula, convert a measurement or clean your data—with clear methods and results on your device.
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Understand your pay, compare borrowing and look at the bigger picture.
Clean a table, fix a file or turn a messy draft into something useful.
Explore physics, geometry and statistics, with the units and assumptions explained.
Convert a measurement, plan a project or get dates and quantities right.
Explore all categories ↗126 recent additions across regional finance, accounting, maths, physics and specialist units.
England and Northern Ireland standard SDLT: Apply standard residential SDLT bands: 0% to £125,000; 2% to £250,000; 5% to £925,000; 10% to £1.5m; 12% above.
Canadian mortgage semiannual compounding: Convert semiannual nominal rate j to monthly rate (1+j/2)^(1/6)−1, then apply the standard monthly amortising-payment formula.
FIFO inventory issue cost: Issue units from the oldest purchase layer first; sum issued units × layer cost, retaining unissued layers in closing inventory.
Ideal projectile horizontal range: For equal launch and landing heights without drag, horizontal range = v² sin(2θ)/g.
Custom country or state progressive tax worksheet: Apply each supplied marginal rate only to the income slice between consecutive cumulative upper bounds, then sum all band taxes.
Density converter: Convert density by multiplying the input by its source-unit factor and dividing by its destination-unit factor.
From your next payslip to your next home project.
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Simple tools you’ll come back to.
Percentage: value × percentage ÷ 100
Loan payment / EMI: Monthly payment = P×r/[1−(1+r)^−n], r=annual/12; at zero interest P/n
Length converter: result = amount × source factor ÷ destination factor. Factors are relative to m.
Word and character count: Count whitespace-delimited words and Unicode code points
Date difference: Signed calendar days = (UTC end − UTC start)/86,400,000; optional inclusive end
JSON validator and formatter: Parse JSON without executing it, then serialize with two-space indentation
Worked examples and plain-language guides to the details that matter.
Browse 29 practical guides ↗Get useful answers from projectile, pressure, gas and lens formulas by checking SI units, sign conventions and the conditions each model assumes.
Compare standard SDLT, LBTT and LTT using the same price, then check the reliefs and surcharges each simple estimate leaves out.
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