What this converter works out
This converter combines a body measurement with your desired ease to give a target finished size, then compares that against the pattern's finished size and describes the fit it will produce.
Ease is the difference between the body and the garment. Choosing it deliberately is what separates a garment that fits from one that merely matches a size label.
Garment measurements
Ease guide
Negative ease is smaller than the body. Zero ease is close fitting. 5–10cm is often relaxed, while 15cm+ is oversized, depending on style and yarn.
Before you choose a size
- Measure the body, not a garment, around the fullest part of the chest or bust with the tape level and not pulled tight.
- Patterns quote finished measurements, which already include the designer's intended ease. Choosing by finished size rather than by body size is the reliable approach.
- Ease is a preference, not a rule. The same body measurement supports a fitted garment and an oversized one.
- Units can be mixed — the converter accepts centimetres or inches independently for each field.
Negative ease, where the garment is smaller than the body, suits stretchy ribbed and close-fitting designs. Zero to 5 cm gives a neat fit. 5 to 12 cm is comfortable everyday ease for a jumper worn over a shirt. Above that is deliberately oversized. Most patterns state their intended ease, and following it produces the garment as designed.
How this calculator works
Body plus ease, compared against the pattern:
Target finished size = body measurement + desired ease
Actual ease of the pattern = pattern finished size − body measurement
Fit described from the actual easeAll three inputs are converted to centimetres before comparison, so they can be entered in whichever unit each source uses. One inch is exactly 2.54 cm.
Worked example: a 96 cm chest
Using the default figures — a 96 cm body measurement, 10 cm of desired ease, a pattern finishing at 106 cm:
- Target finished size: 106 cm, or 41.7 inches
- The pattern's actual ease: 10 cm
- Fit: comfortable ease
The pattern matches the target exactly here. Choosing the next size up — often 112 cm — would give 16 cm of ease and an oversized fit, which may be what you want and is a decision rather than an accident. Knitters who habitually choose by dress size rather than finished measurement are usually making that decision without noticing.
Common mistakes
- Choosing by clothing size. Pattern sizes do not correspond to shop sizes.
- Measuring over bulky clothing. Measure the body.
- Ignoring the pattern's stated ease. It is part of the design.
- Pulling the tape tight. It should be level and just snug.
- Forgetting that gauge overrides all of this. The right size at the wrong gauge still does not fit.
Frequently asked questions
What is ease?
The difference between the body measurement and the garment's finished measurement. Positive ease means the garment is larger than the body; negative ease means smaller, which works for stretchy fabrics. Most fitted jumpers use 5 to 10 cm; oversized designs use 15 or more. It is the single biggest determinant of how a garment looks.
Which measurement should I use?
For a jumper or cardigan, the chest or bust at its fullest point. Upper arm circumference and body length matter too and are worth checking against the pattern's schematic, since a garment can fit at the chest and be tight at the arm. Most well-written patterns include a diagram with all the finished measurements.
Should I knit the same size in every pattern?
No. Designers use different amounts of ease, so the size that works in one pattern may not in another. Always compare the pattern's finished measurement against your target, which is what this converter is for. The size letter or number is a label, not a specification.
Can I knit between sizes?
Often, by working the stitch counts for one size and the length for another, or by adjusting at the side seams. Grading between sizes at the waist and hip is straightforward on a plain garment and much harder where a stitch pattern repeats across the width. Checking the repeat before deciding avoids a great deal of unpicking.
Is what I enter stored?
No. Measurements are processed in your browser and never transmitted or retained.
Related tools
References
- GOV.UK — clothing sizing standards and consumer information
- MoneyHelper — getting value from hobby projects
Sources are checked at publication and can change — how I choose and check references.