% units
    1161 units, 53 prefixes

    You have: grains
    You want: pounds
            * 0.00014285714
            / 7000
    You have: ergs/hour
    You want: fathoms kg^2 / day
    conformability error
            2.7777778e-11 kg m^2 / sec^3
            2.1166667e-05 kg^2 m / sec
    You have: jansky
    You want:
            Definition: fluxunit = 1e-26 W/m^2 Hz = 1e-26 kg / s^2 
    You have: cm^3
    You want: gallons
            * 0.00026417205
            / 3785.4118
    You have: arabicfoot-arabictradepound-force
    You want: ft lbf
            * 0.7296
            / 1.370614
    You have: furlongs/fortnight
    You want: m/s
            * 0.00016630986
            / 6012.8727
    You have: 2 ft 3 ft 12 ft
    You want: stere
            * 2.038813
            / 0.49048148
    You have: $ 5 / yard 
    You want: cents / inch
            * 13.888889
            / 0.072
    You have: 12 ft + 3 in
    You want: cm
            * 373.38
            / 0.0026782366
    You have: 2 btu + 450 ft-lbf
    You want: btu
            * 2.5782804
            / 0.38785542

    % units -v
    1161 units, 53 prefixes

    You have: grain
    You want: aeginamina
            grain = 0.00010416667 aeginamina
            grain = (1 / 9600) aeginamina