Physics
SI Unit Conversion & Dimensional Check Calculator
Enter supported unit symbols with multiplication, division and integer powers, such as N/m or kg*m/s^2.
Your measurements
Start with the example, or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or uploads.
Result & working
ExampleThe calculator is loading. You can read the worked example below.
Step-by-step working
The formula
Value_target = Value_source × source SI factor / target SI factor
1 cm² = (10⁻² m)² = 10⁻⁴ m²
| Symbol | Meaning |
|---|---|
| Base units | kg, m, s, A, K; also dimensionless 1 and rad. |
| Length / time | km, cm, mm, um (μm), nm; ms, min, h. |
| Other supported symbols | g, mA, N, J, eV, W, V, mV, ohm (Ω), kohm, C, Hz, kHz, MHz, Pa, kPa, T, F, L, mL, deg. |
When to use this calculator
Check an equation by comparing dimensions of its two sides. Matching dimensions are necessary but do not prove that a coefficient or a physical model is correct. Formal dimensional-analysis problem solving is not the objective of this helper.
Operations are read left to right; use explicit powers and products. Write kg*m*s^-2 or kg*m/s^2. Parentheses, addition, equation parsing and Celsius offsets are not supported. Symbols are case-sensitive: m is metre and M is not a standalone unit.
To find gradient units, divide vertical-axis units by horizontal-axis units. To find area units, multiply them. Convert before fitting when axes use different scale factors.
Worked example
The calculator opens with these example values. All steps below are available even with JavaScript disabled.
- Both expressions have dimensions m^2.
- Convert to SI: 2.5 × 0.0001 = 0.00025.
- Convert from SI: 0.00025 / 1 = 0.00025 m^2.
0.00025 m^2
Common mistakes
- Square or cube the conversion factor for area or volume.
- A dimensionless ratio can still have a meaningful physical interpretation.
- Use K, not Celsius, where an absolute thermodynamic temperature is needed.