Conversion Calculator — Custom Unit Converter
A flexible converter for any pair of units. Enter the value, type the unit names for your own reference, and supply the conversion factor (how many "to" units equal one "from" unit). The calculator multiplies and shows both the direct and inverse factors.
Result of multiplying the input value by the conversion factor
- 1
Apply conversion factor
1 × 2.54 = 2.540000Multiply the input by the factor (how many "to" units equal 1 "from" unit) - 2
Inverse factor (to convert back)
1 ÷ 2.54 = 0.39370079
How does this calculator work?
Multiply any value by a known conversion factor. Enter the factor (e.g. 2.54 for inches → cm), and the calculator gives the result and the inverse factor for converting back. Label the units for your own reference — the math works for any ratio-based unit pair.
Formula
How this is calculated
Every unit conversion reduces to multiplication by a constant factor. For example, 1 inch = 2.54 cm, so to convert 5 inches to centimetres you multiply 5 × 2.54 = 12.7 cm. This calculator lets you supply any factor you know — from an engineering datasheet, an obscure industry standard, or a currency rate — without being limited to a fixed list of units.
The inverse factor (1 ÷ factor) is shown so you can convert in the opposite direction: if 1 inch = 2.54 cm, then 1 cm = 1/2.54 ≈ 0.3937 inches. Both directions use exact arithmetic with no rounding inside the computation.
For common physical quantities (length, weight, temperature, speed, data storage, etc.), the platform's dedicated converters apply verified NIST factors automatically. This calculator is best for domain-specific or custom ratios — currency rates, proprietary unit systems, recipe scaling multipliers, or any conversion where you already know the factor.
Frequently asked questions
Engineering standards bodies (NIST, ISO), textbooks, and reference tables list exact factors. For currency, use a live exchange rate from a financial data provider. For recipe scaling, the factor is simply the batch multiplier (e.g. 3 to triple a recipe).
Swap the value and use the shown inverse factor (1 ÷ factor). Alternatively, type the result as the new value and use the inverse factor as the conversion factor — the math is symmetric.
Temperature conversions (Celsius ↔ Fahrenheit ↔ Kelvin) involve an additive offset as well as a multiplicative factor (e.g. °F = °C × 9/5 + 32), so they cannot be handled by a single multiplicative factor alone. Use the dedicated Temperature Converter for those.
TG we-Calculate Editorial Team. (2026). Conversion Calculator — Custom Unit Converter [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/conversion-calculator
TG we-Calculate Editorial Team. "Conversion Calculator — Custom Unit Converter." TG we-Calculate. 2026. https://we-calculate.com/calculator/conversion-calculator.
TG we-Calculate Editorial Team, "Conversion Calculator — Custom Unit Converter," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/conversion-calculator
@misc{wecalculate_conversion_calculator, title = {Conversion Calculator — Custom Unit Converter}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/conversion-calculator}}, year = {2026}, note = {TG we-Calculate} }
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