GageBlockCalc
Free inch & metric gage block stack calculator. Fewest blocks, no login.
How to build a gage block stack
- Choose your set (inch 81, 36, or 28; metric 112 or 88).
- Enter the target dimension in the same unit as the set.
- Optionally include wear / protection blocks so the working faces stay protected.
- Read the primary (fewest-block) combination, then copy, share, or print a shop ticket.
Gage blocks (also called gauge blocks or slip gauges) wring together into a precise length. This calculator uses the classic digit-by-digit method machinists learn in the shop: clear the rightmost digits first so you use as few blocks as possible.
Works offline as an installable app. Built for toolrooms, QC, and hobby CNC.
Gage block FAQ
What gage block set should I buy?
An 81-piece inch rectangular set (Mitutoyo / Starrett style) covers most shop work in 0.0001" steps. A 36-piece kit is lighter for coarser targets. A 28-piece thin set fills tiny steps. Metric shops usually start with a 112-piece or 88-piece set. Pick your set above, build stacks here for free, then use the shop links if you need to buy one.
What are wear or protection blocks?
Wear blocks are sacrificial end blocks, commonly two 0.050" blocks on inch sets or two 1 mm blocks on metric sets. They are wrung on the outside of a stack so contact wear hits them instead of the precision set. Turn on the wear toggle and the calculator includes them in the total.
How does this calculator choose the fewest blocks?
Enter a target in the same unit as the set you picked. The primary result is the stack with the fewest blocks that adds up to that target. If two stacks use the same number of blocks, the calculator prefers blocks you have used less often on this device. You can copy, share, or print that stack.
Should I use inch or metric gage blocks?
Use one set at a time. Inch sets are 81, 36, or 28 pieces. Metric sets are 112 or 88 pieces. Type the target in that set's unit, inches or millimeters. This calculator does not mix inch and metric blocks in the same stack.
Is this gage block calculator free?
Yes. The stack calculator stays free, with no account and no login. It runs in your browser and can be installed for offline use. Optional Amazon links may earn a commission (Amazon Associates).
Do I need a gage block stone?
A serrated gage block stone knocks down light nicks and burrs so blocks wring again. Keep it clean, because grit on the stone can lap and change size. It does not replace badly damaged blocks.
How often should gage blocks be calibrated?
Many shops start at 12 months for a working set, 6 months when blocks are used every day, and longer for a master set that is rarely handled. Your quality system and any customer requirement set the real interval. The gage block calibration interval guide explains how to choose and adjust one.
How do I check a micrometer with gage blocks?
A zero check only shows that the anvils meet. Check several sizes across the range so the spindle stops at different thimble positions. On a 0 to 1 inch micrometer, common sizes are 0.105, 0.210, and 0.315 inch. Build each stack in this calculator, then follow the how to check a micrometer with gage blocks guide.