Why put these two on a shortlist?
Both manufacturers identify 100% merino wool and publish 28 stitches per 10 cm. That makes this a useful first comparison for a pattern asking for a fine merino yarn. It does not establish identical fabric: ply structure and twist are not verified in these records, and Knitting for Olive publishes 38 rows while Sunday’s captured page gives no row gauge.
Count length before counting balls
Knitting for Olive Merino contains 250 m per 50 g; Sunday contains approximately 235 m. For an illustrative 1,000 m requirement, four Merino balls cover the stated length exactly, whereas Sunday needs five whole balls. This is package arithmetic, not a project recommendation: your washed gauge, pattern size and swatching allowance can change the amount needed.
Care and US sourcing
Sandnes explicitly describes Sunday as non-superwash and provides guidance for a separate wool wash program. Knitting for Olive specifies a cool hand wash and flat drying. Follow the relevant label rather than transferring one brand’s wash instructions to the other. Mother Knitter lists Sunday and Heavenly Yarns lists Merino; their dated evidence is linked in the table. Confirm the desired color, dye lot and quantity directly with the retailer.
What to check in your swatch
Use the pattern’s stitch and strand arrangement. Wash and dry the sample as you would the finished piece, then measure stitch and row gauge away from its edges. If the pattern shapes a yoke over a fixed number of rows, matching width alone is not enough. Check the feel and stability of the fabric before adjusting needles just to reach a number.
Specification sources: Sandnes Garn Sunday. Knitting for Olive Merino. Sources and retail evidence are detailed below. These are desk comparisons; no physical testing has been performed.