# Spring Wire Length

on . Posted in Fastener

Spring wire length, abbreviated as $$L_c$$ and $$L_t$$, is the wire used to make a coil spring and is based on the number of coils, the mean coil diameter, and the pitch of the coils.

### Compression Spring Wire Length formulas

$$L_c = \pi \; D$$    (one coil wire length)

$$L_t = L_c \; n_t$$     (total wire length)

Symbol English Metric
$$L_c$$ = coil wire length $$in$$ $$mm$$
$$L_t$$ = total wire length $$in$$ $$mm$$
$$\pi$$ = Pi  $$3.141 592 653 ...$$
$$D$$ = mean coil diameter $$in$$ $$mm$$
$$n_t$$ = total number of coils $$dimensionless$$

### Extension Spring Wire Length formulas

$$L_c = \pi \; D$$    (one coil wire length)

$$L_t = L_c \; ( n_t + 2 \; h )$$     (total wire length)

Symbol English Metric
$$L_c$$ = coil wire length $$in$$ $$mm$$
$$L_t$$ = total wire length $$in$$ $$mm$$
$$\pi$$ = Pi $$3.141 592 653 ...$$
$$D$$ = mean coil diameter $$in$$ $$mm$$
$$n_t$$ = total number of coils $$dimensionless$$
$$h$$ = height of 2 coils (hooks) $$in$$ $$mm$$

### Extension Spring Wire Length formulas

$$L_c = \pi \; D$$    (one coil wire length)

$$L_t = L_c \; ( n_t + 2 \; h )$$     (total wire length)

Symbol English Metric
$$L_c$$ = coil wire length $$in$$ $$mm$$
$$L_t$$ = total wire length $$in$$ $$mm$$
$$\pi$$ = Pi $$3.141 592 653 ...$$
$$D$$ = mean coil diameter $$in$$ $$mm$$
$$n_t$$ = total number of coils $$dimensionless$$
$$h$$ = leg lengths of one and two extension $$in$$ $$mm$$

Tags: Spring Length