A precise determination of the ground state <sup loc="post">111</sup>In (<math altimg="si1.svg"><mn>9</mn><mo stretchy="false">/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak="badbreak" linebreakstyle="after">+</mo></mrow></msup></math>) electron capture to ground state of <sup loc="post">111</sup>Cd (<math altimg="si2.svg"><mn>1</mn><mo stretchy="false">/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak="badbreak" linebreakstyle="after">+</mo></mrow></msup></math>) Q value has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. A value of 857.63(17) keV was obtained, which is nearly a factor of 20 more precise than the value extracted from the Atomic Mass Evaluation 2020 (AME2020). The high-precision electron-capture Q value measurement along with the nuclear energy level data of 866.60(6) keV, 864.8(3) keV, 855.6(10) keV, and 853.94(7) keV for <sup loc="post">111</sup>Cd was used to determine whether the four states are energetically allowed for a potential ultra-low Q-value β decay or electron-capture decay. Our results confirm that the excited states of 866.60(6) keV with spin-parity (<math altimg="si3.svg"><msup><mrow><mi>J</mi></mrow><mrow><mi>π</mi></mrow></msup></math>) of 3/2<sup loc="post">+</sup> and 864.8(3) keV with <math altimg="si4.svg"><msup><mrow><mi>J</mi></mrow><mrow><mi>π</mi></mrow></msup><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>3</mn><mo stretchy="false">/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak="badbreak" linebreakstyle="after">+</mo></mrow></msup></math> are ruled out due to their deduced electron-capture Q value being smaller than 0 keV at the level of around 20σ and 50σ, respectively. Electron-capture decays to the excited states at 853.94(7) keV (<math altimg="si5.svg"><msup><mrow><mi>J</mi></mrow><mrow><mi>π</mi></mrow></msup><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>7</mn><mo stretchy="false">/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak="badbreak" linebreakstyle="after">+</mo></mrow></msup></math>) and 855.6(10) keV (<math altimg="si4.svg"><msup><mrow><mi>J</mi></mrow><mrow><mi>π</mi></mrow></msup><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>3</mn><mo stretchy="false">/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak="badbreak" linebreakstyle="after">+</mo></mrow></msup></math>), are energetically allowed with Q values of 3.69(19) keV and 2.0(10) keV, respectively. The allowed decay transition <sup loc="post">111</sup>In (9/2<sup loc="post">+</sup>) → <sup loc="post">111</sup>Cd (7/2<sup loc="post">+</sup>), with a Q value of 3.69(19) keV, is a potential new candidate for neutrino-mass measurements by future EC experiments featuring new powerful detection technologies. The results show that the indium level <math altimg="si6.svg"><mn>2</mn><msub><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo stretchy="false">/</mo><mn>2</mn></mrow></msub></math> for this decay branch leads to a significant increase in the number of EC events in the energy region sensitive to the electron neutrino mass.Read less <