Two different quantities, the same 1,000x jump
Running 1 mF through the capacitance converter's real formula, converting to µF, returns 1,000 µF. Running 1 mH through the inductance converter's completely separate real formula, converting to µH, also returns 1,000 µH. Two different physical quantities — electric capacitance and magnetic inductance — measured in unrelated units, and the milli-to-micro step produces the exact same multiplier both times.
The formula: it's the prefixes doing the work, not the physics
The capacitance converter defines milli as 0.001 of a farad and micro as 0.000001 of a farad; the inductance converter defines milli as 0.001 of a henry and micro as 0.000001 of a henry. In both formulas, converting from milli to micro divides by the micro factor and multiplies by the milli factor: 0.001 ÷ 0.000001 = 1,000, regardless of whether the unit underneath is farads or henries. Neither converter's code references the other, yet they produce the same ratio because both simply implement the standard SI prefix system.
The ladder holds at every scale, in both directions
Scaling the input confirms it holds beyond 1 unit: 5 mF converts to 5,000 µF, and 5 mH converts to 5,000 µH — still the same 1,000x relationship. Capacitance's converter goes one rung further than inductance's, down to nanofarads and picofarads, and the pattern continues there too: the real formula returns 1,000 nF for 1 µF, and 1,000 pF for 1 nF, because each step down the metric ladder — milli to micro, micro to nano, nano to pico — is defined as exactly three orders of magnitude, every time.
Why this consistency is useful in practice
Because the prefix ladder is quantity-agnostic, anyone who has memorized "milli to micro is times 1,000" for one kind of component can apply that same mental shortcut to any other SI-based unit — resistance, inductance, capacitance, or otherwise — without re-deriving it. The two converters arrive at identical scaling not because capacitors and inductors behave alike physically, but because both are built on the same universal prefix convention.