Working it out by hand
1 guntha is 1,089 sq ft and 1 sq ft is 1 sq ft. Turn the guntha into square feet first, then into sq ft. For 2.5 guntha:
2.5 guntha × 1,089 = 2,722.5 sq ft
1 गुंठा = 1,089 वर्ग फुट, यानी 33 फुट × 33 फुट का वर्ग। 40 गुंठा = 1 एकड़।
Measured the plot with a tape instead? Use the plot area calculator.