★ CONSTRUCTION · OUTDOOR · CHAINSAWS
A 14 in trunk needs a 16 in bar. The bar must be 2 inches longer than the trunk is thick, so the tip clears the far side of the cut. Enter your trunk diameter to find the bar, or work out how thick a trunk your bar cuts.
A chainsaw bar is sized by the trunk it has to cut: the bar must be at least 2 inches longer than the trunk is thick, so the tip clears the far side of the cut and the chain does not bind. This chart lists the six standard bar lengths with the job each one fits, and the lookup finds the smallest bar that clears your trunk — so the bar you buy is the shortest one that still cuts in one pass.
A chainsaw bar is sized by the trunk it has to cut: the bar must be at least 2 inches longer than the trunk is thick, so the tip clears the far side of the cut and the chain does not bind. The standard bar lengths are 12, 14, 16, 18, 20 and 24 inches. The lookup adds 2 inches to the trunk diameter and takes the smallest standard bar that is at least that long. If the trunk plus 2 inches is longer than 24 inches, the bar is capped at 24 inches, and the trunk has to be cut from both sides.
At the default — a 14 in trunk — the trunk plus 2 inches is 14 + 2 = 16 in, and the smallest standard bar that is at least 16 in is 16 in, which is 16 × 2.54 = 41 cm, rated for general homeowner use. A 16 in bar cuts a trunk up to 14 in thick in one pass.
| Use | Bar length | Bar in cm | Trunk it cuts |
|---|---|---|---|
| Pruning & limbing | 12 in | 30 cm | Up to 10 in |
| Small trees & firewood | 14 in | 36 cm | Up to 12 in |
| General homeowner use | 16 in | 41 cm | Up to 14 in |
| Medium trees | 18 in | 46 cm | Up to 16 in |
| Large trees | 20 in | 51 cm | Up to 18 in |
| Professional felling | 24 in | 61 cm | Up to 22 in |
The table is a bar-length chart, not a chain-pitch or chain-gauge chart and not a saw-maintenance guide: it does not list the chain pitch, the gauge, or how to sharpen, oil or store the saw. It sizes the bar by the trunk, and nothing else.
Setup: trunk diameter 14 in, reverse bar 16 in.
Line 1 — the length the bar must be. 14 + 2 = 16 in. The bar must clear the far side of the trunk, so it has to be 2 inches longer than the trunk is thick.
Line 2 — the smallest standard bar. The standard bars are 12, 14, 16, 18, 20 and 24 in. The smallest one that is at least 16 in is 16 in.
Line 3 — the bar in centimetres. 16 × 2.54 = 40.64, rounded to 41 cm.
Line 4 — the reverse. A 16 in bar cuts a trunk up to 16 − 2 = 14 in thick in one pass, and a 20 in bar cuts up to 20 − 2 = 18 in.
8 in trunk: 8 + 2 = 10 in, and the smallest standard bar that is at least 10 in is 12 in (30 cm), for pruning and limbing. A short bar on a thin trunk is the lightest saw to carry.
12 in trunk: 12 + 2 = 14 in, and the smallest standard bar that is at least 14 in is 14 in (36 cm), for small trees and firewood.
16 in trunk: 16 + 2 = 18 in, and the smallest standard bar that is at least 18 in is 18 in (46 cm), for medium trees.
18 in trunk: 18 + 2 = 20 in, and the smallest standard bar that is at least 20 in is 20 in (51 cm), for large trees.
20 in trunk: 20 + 2 = 22 in, and the smallest standard bar that is at least 22 in is 24 in (61 cm), for professional felling.
24 in trunk: 24 + 2 = 26 in, which is longer than the longest standard bar, so the bar is capped at 24 in (61 cm) — cut from both sides. The bar does not clear the trunk in one pass, so the cut is made from each side and the two cuts meet in the middle.
30 in trunk: 30 + 2 = 32 in, which is longer than the longest standard bar, so the bar is capped at 24 in (61 cm) — cut from both sides. A trunk this thick is a two-sided cut with the longest bar, or a job for a bigger saw.
Reverse — the bars: a 16 in bar cuts a trunk up to 14 in thick, a 20 in bar cuts up to 18 in, a 24 in bar cuts up to 22 in, and a 14 in bar cuts up to 12 in. If you already own the saw, the reverse tells you the thickest trunk it cuts in one pass.
The model assumes the bar is measured in inches from the saw body to the tip, the trunk is round, and the cut is made across the grain. It assumes the 2-inch clearance is enough for the tip to clear the far side: a trunk that is not round, or a cut that is not square, needs more clearance. It leaves out the chain pitch, the gauge, the engine size, and the weight of the saw — a bar that fits the trunk is no good on a saw too small to drive it, so check the saw manual for the longest bar the saw takes. Rounding convention: bar lengths are standard sizes in whole inches, centimetres are rounded to whole numbers, and all figures are computed from the table, not rounded.
| Output | Formula | What it means |
|---|---|---|
| Recommended bar | smallest standard bar ≥ trunk diameter + 2 in | (41 cm). |
| Bar in cm | bar in inches × 2.54, rounded | 41 cm. |
| Trunk + 2 in | trunk diameter + 2 in | 16 in needed. |
| Best for | table value for the bar | General homeowner use. |
| 8 in trunk | same lookup | (30 cm) — pruning & limbing. |
| 12 in trunk | same lookup | (36 cm) — small trees & firewood. |
| 16 in trunk | same lookup | (46 cm) — medium trees. |
| 18 in trunk | same lookup | (51 cm) — large trees. |
| 20 in trunk | same lookup | (61 cm) — professional felling. |
| 24 in trunk | same lookup, capped at 24 in | (61 cm) CAPPED — cut from both sides. |
| 30 in trunk | same lookup, capped at 24 in | (61 cm) CAPPED — cut from both sides. |
| Reverse: 16-in bar | bar length − 2 in | Max trunk 14 in. |
| Reverse: 20-in bar | bar length − 2 in | Max trunk 18 in. |
| Reverse: 24-in bar | bar length − 2 in | Max trunk 22 in. |
| Reverse: 14-in bar | bar length − 2 in | Max trunk 12 in. |
The math is exact for the table: the lookup adds 2 inches to the trunk diameter and takes the smallest standard bar that is at least that long, capping at 24 inches. What the model cannot do is measure your trunk for you: measure the thickest trunk you plan to cut, across the cut, and use that number. It is a bar-length chart, not a chain-pitch or chain-gauge chart and not a saw-maintenance guide — it does not list the pitch, the gauge, or how to sharpen or oil the saw. It leaves out the engine size and the weight of the saw: check the saw manual for the longest bar the saw takes. For the wire for the same yard, see extension cord size chart; for the cost of the deck the firewood sits on, see deck cost calculator.
Bright Side Kit. "Chainsaw Bar Size Chart: Pick the Right Bar Length." https://brightoolbox.com/chainsaw-bar-size-chart/ Accessed October 25, 2026.A 16 in bar. The bar must be 2 inches longer than the trunk, so 14 + 2 = 16 in, and 16 in is a standard bar size. That is 41 cm, rated for general homeowner use.
Add 2 inches to the trunk diameter. Take the thickest trunk you plan to cut, add 2 inches, and take the smallest standard bar that is at least that long: 12, 14, 16, 18, 20 or 24 in. If the trunk plus 2 inches is over 24 in, the bar is capped at 24 in and you cut from both sides.
A 24 in bar. 20 + 2 = 22 in, and the smallest standard bar that is at least 22 in is 24 in, which is 61 cm and rated for professional felling.
Up to 14 in thick. The bar must be 2 inches longer than the trunk, so a 16 in bar cuts a trunk up to 16 − 2 = 14 in in one pass. A 20 in bar cuts up to 18 in, and a 24 in bar cuts up to 22 in.
Cut from both sides. The longest standard bar is 24 in, so a 24 in trunk needs 26 in of bar and is capped at 24 in. Cut from one side, then from the other, and the two cuts meet in the middle.
No. A longer bar is heavier, harder to control, and needs a bigger engine to drive it. The right bar is the smallest one that clears the trunk by 2 inches — a 12 in bar for pruning, a 16 in bar for a 14 in trunk.
Multiply inches by 2.54. A 16 in bar is 41 cm, a 20 in bar is 51 cm, and a 24 in bar is 61 cm. The chart lists both inches and centimetres for every bar.
No. This chart sizes the bar by the trunk only. It does not list the chain pitch, the gauge, or how to sharpen, oil or store the saw — check the saw manual for those.