Mashed Potatoes Calculator — How Much to Buy
Planning to make mashed potatoes for a crowd? Enter the number of servings and your potato variety and get the exact raw weight to buy, plus butter and milk quantities — already adjusted for cooking losses.
Potato variety
Weight before peeling and cooking, to yield the right amount of mash
- 1
Mash needed
6 × 200 = 1,200Standard serving is 200 g of finished mashed potato per person - 2
Yield fraction
80%Weight remaining after peeling and boiling for this potato variety - 3
Raw potato (g)
1,200 ÷ 0.8 = 1,500 - 4
Raw potato (kg)
1,500 ÷ 1000 = 1.50
How does this calculator work?
Allow 200 g finished mash per person, then divide by the potato variety yield (Russet ~80%, Yukon ~84%) to find how much raw potato to buy. For 6 servings of Russet mash that is about 1.5 kg raw potatoes, plus 90 g butter and 360 ml milk at standard proportions.
Formula
How this is calculated
A standard serving of mashed potatoes is approximately 200 g (about 7 oz) of finished mash. Because peeling and boiling reduce a potato's weight — typically by 16–20% depending on variety — you need more raw potato than the finished weight suggests. The calculator divides the total finished mash weight by a variety-specific yield fraction to arrive at the raw purchase weight.
Russet (Idaho) potatoes yield about 80% after peeling and boiling because of their thicker skin and lower moisture; Yukon Gold potatoes yield around 84% because of their thin skin and dense flesh. Other white potatoes fall around 82%. These are empirical averages from recipe testing and may vary by exact potato size and cooking method.
Butter and milk quantities use standard recipe proportions — roughly 15 g butter and 60 ml milk or cream per serving — and can be scaled up or down with the multiplier fields. Multiply milk by 0.5 for a stiffer mash, or by 1.5 and substitute cream for a richer result. Yields are estimates; individual potatoes vary, so buy about 5–10% extra for safety.
Frequently asked questions
Allow roughly 250 g (about 9 oz) of raw, unpeeled potato per person for a standard serving of mashed potatoes. This accounts for the ~18–20% weight lost to peeling and boiling, leaving about 200 g of finished mash per serving.
Russet (Idaho) potatoes are the most popular for their fluffy, starchy texture. Yukon Gold are preferred for a naturally creamy, slightly buttery flavour and a denser mash. Waxy potatoes like red or new potatoes are generally not recommended — they can become gluey when over-mashed.
Yes. Cook and mash them up to a day in advance, then keep them warm in a slow cooker on low or reheat on the stove with a splash of warm milk stirred in. Add butter and seasoning just before serving to maintain the best texture.
Also known as
TG we-Calculate Editorial Team. (2026). Mashed Potatoes Calculator — How Much to Buy [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/mashed-potatoes-calculator
TG we-Calculate Editorial Team. "Mashed Potatoes Calculator — How Much to Buy." TG we-Calculate. 2026. https://we-calculate.com/calculator/mashed-potatoes-calculator.
TG we-Calculate Editorial Team, "Mashed Potatoes Calculator — How Much to Buy," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/mashed-potatoes-calculator
@misc{wecalculate_mashed_potatoes_calculator, title = {Mashed Potatoes Calculator — How Much to Buy}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/mashed-potatoes-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?