Tilia cordata is a
tree growing to 20–40 m (66–131 ft) tall, diameter 1/3 to 1/2 the height, with a trunk up to 1 m diameter. The bark is smooth and grayish when young, firm with vertical ridges and horizontal fissures when older. The crown is rounded in a formal oval shape to pyramidal. Branching is upright and increases in density with age.
leaves are alternately arranged, rounded to triangular-ovate, 3–8 cm long and broad, mostly hairless (unlike the related
Tilia platyphyllos) except for small tufts of brown hair in the leaf vein axils - the leaves are distinctively heart-shaped. The
buds are alternate, pointed egg shaped and have red scales. It has no terminal bud.
 The small yellow-green
flowers are produced in clusters of five to eleven in early summer with a leafy yellow-green subtending
bract, have a rich, heavy scent; the trees are much visited by
bees to the erect flowers which are held above the bract; this flower arrangement is distinctly different from that of the Common Lime
Tilia × europaea where the flowers are held beneath the bract. The
fruit is a dry nut-like
drupe 6–7 mm long by 4 mm broad containing one, or sometimes two, brown seeds (infertile fruits are globose), downy at first becoming smooth at maturity, and (unlike T. platyphyllos and also T. x europaea) not ribbed but very thin and easily cracked open.