R = ρL/A, and the weight that goes with it. Two directions: from a diameter you already have, or from the resistance your design needs.
Outputs use nominal resistivity at 20 °C and assume a uniform, fully annealed wire. Real lots carry a measured resistance per metre, printed on every spool label — that value, not this estimate, is what your inspection report will state. For resistance alloys the figure also moves with temperature; see each grade's TCR on its datasheet.
A 1 % error in diameter is a 2 % error in resistance. At 0.05 mm that is the difference between a shunt that meets its tolerance and one that does not — which is why fine gauges carry a tolerance, not just a nominal size.
Doubling the length doubles the resistance and doubles the weight. If a design is marginal, cutting length is a cheaper fix than changing grade — and it is reversible.
Send the target Ω/m, the operating temperature and the diameter your process can handle. We will propose the grade and confirm what we can hold before production.
Send a specification Grade cross-reference