How do I find the largest and smallest size of a toleranced dimension?

Add the plus deviation to the size for the largest size, and take off the minus deviation for the smallest. With limit dimensioning the two sizes are written out: top is largest, bottom is smallest.

Mechanical prints: lesson 6 of 7Harder

Work out the limits

Work out the size the question asks for and type it. Get 10 right to finish.

What is the total tolerance on this dimension?

Worked examples

Callout	Largest	Smallest	Total tolerance
1.250 +.003 / -.001	1.253	1.249	.004
.750 ±.005	.755	.745	.010
16.00 +0.05 / -0.10	16.05	15.90	0.15
25.00 0 / -0.02	25.00	24.98	0.02

How to type the answer

Type the number as it would be written on the drawing: 1.253, .004 or 15.90. A comma works as the decimal sign too (15,90). The unit is optional. If you are stuck after two tries, you can show the answer.

Questions

How do I find the largest and smallest size of a toleranced dimension?: Add the plus deviation to the size for the largest size, and take off the minus deviation for the smallest. With limit dimensioning the two sizes are written out: top is largest, bottom is smallest.
What is the total tolerance?: The largest size minus the smallest size. 1.253 and 1.249 give a total tolerance of .004.

Explained in our own words and checked against several textbooks and published tables. For the full rules, see ASME Y14.5, ASME Y14.36, ISO 286, ISO 965, ISO 1302 and ISO 21920-1.