You can measure your upgrade level in the tools menu. Every 100% is an upgrade and will denote the level you can upgrade to with a miniature ore icon of the appropriate level.
When the player receives the sickle, it will start at a tool level of one. The sickle can be upgraded up to a level of seven, and becomes more and more useful with every upgrade. Below is a list of upgrades that can be made to the sickle throughout the game. Upgrades are made at the Blacksmith's by Saibara.
|Tool Level||Upgrade Cost||Abilities|
|Standard Sickle (Level 1)||Sickle that you start with.||Cut a single square of grass.|
|Copper Sickle (Level 2)||Copper Ore + 1,000G||Cuts a 1x3 square of grass.|
|Silver Sickle (Level 3)||Silver Ore + 2,000G||Cuts a 2x3 square of grass.|
|Gold Sickle (Level 4)||Gold Ore + 3,000G||Cuts a 3x3 square of grass.|
|Mystrile Sickle (Level 5)||Mystrile Ore +5,000G||Cuts a 5x5 square of grass.|
|Cursed Sickle (Level 6)||Find on Floor 79 of the Lake Mine||Cuts a 9x9 square of grass.|
|Blessed Sickle (Level 6)||Equip the Cursed Sickle for 10 consecutive days.|
|Mythic Sickle (Level 7)||Mythic Stone + 50,000G||Cuts a 15x15 square of grass.|