Life Jacket Size Calculator
Life jacket band and type from weight, chest, water, and swim skill.
What it does
Life jackets size by weight first, chest second: a 42 lb child wears Child band foam whether tall or short, and calm water takes Type II while rough water demands Type I. Labels close every call.
The tool above takes weight with chest, water, and swim strength. It returns the size band with the type and fit check.
The default 42 lb child on calm water takes Child Type II foam at 7 lb minimum. A 70 lb youth takes Youth band; rough water upgrades all to Type I.
Bands follow USCG boating safety with Coast Guard selection guides and ACA fitting behind them. All three agree on 33/55/88 and the lift test used here.
How to use
- Enter body weight.
- Enter chest inches.
- Pick calm or rough water.
- Pick swim strength.
- Read size band first.
- Run the lift test.
Formula
- weight
- Body weight in pounds.
- chest
- Chest circumference in inches.
- 33/55/88
- Band edges in pounds.
Exact cuts use over versus at-or-under wording (33, 55, 88 boundary pounds step up). Chest validates 10 to 80 in with adult universal spanning 30 to 52 in. Labels and water tests rule ties.
Worked example
Example: 42 lb child kayaking
Defaults: 42 lb, 24 in chest, calm water, weak swimmer.
- Child: 42 lb, 24 in chest, calm lake.
- Band: over 33 to 55 = Child.
- Label: 42 sits inside 30 to 50.
- Type: calm water, weak swimmer = Type II foam.
- Buoyancy floor: 7 lb child Type II.
- Fit: fasten all, lift by shoulders, no slip.
- Tool shows Child (33 to 55 lb), Type II foam.
Reference table
| Band | Weight | Min foam |
|---|---|---|
| Infant | To 33 lb | Varies |
| Child | 33 to 55 lb | 7 lb Type II |
| Youth | 55 to 88 lb | 11 lb Type II/III |
| Adult | Over 88 lb | 15.5 to 22 lb |
Limits
- Guidance only; labels rule.
- State wear laws vary.
- Inflatables adult-only practice.
- Newborns need pool testing.
Common mistakes
- Sizing by age not weight.
- Skipping the lift test.
- Using damaged foam.
- Inflatables for weak swimmers.
- Ignoring state under-13 laws.
Try it yourself
Quick checks. Answers sit tucked under each question.
70 lb youth?
Over 55 to 88: Youth band.
200 lb strong swimmer, rough water?
Adult over 88, rough water: Type I offshore vest.
Exactly 33 lb?
At 33 exactly: Child band by over-33 wording, confirm label.
Questions
What are the weight bands?
Infant to 33, Child 33 to 55, Youth 55 to 88, Adult over 88 lb. Labels confirm.
What do the types mean?
I offshore, II near-shore, III flotation aid, V special use only per label.
How is fit checked?
Fasten all, arms up, lift by shoulders: snug with no ride past chin or ears, then water-test.
Which type for calm lakes?
Type II or III for calm inland with fast rescue; Type I offshore and rough.
Can kids wear inflatables?
No: inflatables run adult-only in practice and never for weak swimmers.
Do states add rules?
Yes: under-13 wear laws vary by state, and state rules control its waters.