A tolerance calculator that I, an engineer of an automobile company, made for myself. For tolerance calculation, it is possible to calculate cumulative tolerance by specifying root sum square (R.S.S.) or linear sum (L.S.) for each tolerance. Under the designed size and tolerance, the probability of occurrence of a certain size can also be calculated.
(If you like, please use a paid version, “ToleranceCalculator2”. You can calculate up to 10 numbers. It is easier to use and has been improved.)

Cumulative tolerance calculation:
Tap the [accumulation] button in the title bar.
e.g.
- Touch the entry field of size in raw [A], and input “5”.
- Touch the entry field of tolerance in raw [A], and input “0.2”.
- Touch the entry field of size in raw [B], and input “4”.
- Touch the entry field of tolerance in raw [B], and input “0.2”.
- Touch the entry field of size in raw [C], and input “3”.
- Touch the entry field of tolerance in raw [C], and input “0.1”.
- Tap the [Calc.] button.
-> Resulting the cumulative size and tolerance , 12 +/- 0.5.

Switching L.S and R.S.S
- … continuation of the above…
- Tap the toggle buttons in raw [A] to [C], and choose [Square].
- Tap the [Calc.] button.
-> Resulting the cumulative size and tolerance , 12 +/- 0.3.

Probability calculation:
Tap the [probability] button in the title bar.
e.g. Designed the size and tolerance 12.0 +/- 0.3 in 3 sigmas, calculation of the probability that the size of 12.4 and larger happens.
- Input 12 in size field and 0.3 in tolerance field in Defined value raw.
- Tap the button under the tolerance, and choose 3
- Input 12.4 in the Test value field.
- Chose [and bigger] by tapping the button in Test value raw.
- Tap the [Calc.] button.
-> Resulting the probability is 3.2ppm, i.e. it happens once in 31574 times.