{"_id":"6ae0d65f811dbf48caf18ffe","slug":"how-long-to-boil-potatoes","__v":0,"author":"Om Vaghani","content":"*By Om Vaghani, editor at ClockAura (ConnectGo Infoware). Published 27 October 2026.*\r\n\r\nBoiling potatoes sounds like the easiest job in the kitchen, and it mostly is. The trouble is that \"boil until tender\" covers a huge range. A tray of small new potatoes and a pot of big whole floury ones can be ten or fifteen minutes apart. Get it wrong one way and the middle is still hard. Get it wrong the other way and they fall apart into the water.\r\n\r\n## The short answer\r\n\r\nTiming starts once the water has come back to a gentle boil after the potatoes go in.\r\n\r\n| Cut | Approximate size | Boiling time |\r\n|---|---|---|\r\n| Small new or baby potatoes, whole | 3-4 cm across | 12-15 min |\r\n| Medium potatoes, whole | 6-7 cm across | 20-25 min |\r\n| Large potatoes, whole | 8-10 cm across | 25-30 min |\r\n| Medium potatoes, halved | halves about 4-5 cm thick | 15-20 min |\r\n| Quartered (large potatoes) | chunks about 4 cm | 15-18 min |\r\n| Cubed for mash or salad | 2.5 cm (1 inch) cubes | 10-15 min |\r\n| Small dice | 1-1.5 cm cubes | 6-10 min |\r\n| Thick slices | 1.5-2 cm thick | 8-12 min |\r\n| Parboiling for roast potatoes | 4-5 cm chunks | 8-10 min |\r\n\r\nThese are typical kitchen ranges, not exact numbers, and you should treat them as the point to start checking. The size of the pieces matters far more than the weight of the batch, and the variety of potato shifts things by a few minutes either way.\r\n\r\n## Why size beats everything\r\n\r\nHeat travels from the outside of a potato to its centre. The thicker the piece, the further the heat has to travel, and the outside keeps cooking while the middle catches up. That is why big whole potatoes often end up crumbly on the outside and firm in the middle.\r\n\r\nThe practical fix is simple: **cut your potatoes to the same size.** A pot of evenly sized chunks cooks evenly. A pot of mixed sizes gives you a mix of mush and hard bits. If you are boiling whole potatoes, pick ones of a similar size, or cut the large ones in half so they match the smaller ones.\r\n\r\n## Floury vs waxy potatoes\r\n\r\nPotatoes fall roughly into two groups.\r\n\r\n**Floury (starchy) potatoes** such as Russet, Maris Piper and King Edward have a dry, fluffy flesh. They are the best choice for mash, roasting and baking. They also break up more easily when boiled, so watch them towards the end and do not boil them hard.\r\n\r\n**Waxy potatoes** such as new potatoes, Charlotte and many red-skinned types hold their shape well. They are ideal for potato salad and for serving whole with butter and herbs. They can take a few minutes longer to feel fully tender, but they rarely fall apart.\r\n\r\nMany everyday supermarket potatoes sit somewhere between the two and work well for most jobs.\r\n\r\n## Cold water or boiling water?\r\n\r\nFor whole potatoes and large chunks, **start them in cold, salted water** and bring it up to the boil. The outside and inside heat more evenly, so the outside is less likely to turn to mush before the middle is cooked.\r\n\r\nFor small pieces, either way works. Starting in cold water is still a little more forgiving, and it is the method most of the times above are based on, counting from when the water reaches a boil.\r\n\r\nUse enough water to cover the potatoes by about 2-3 cm, and add a good pinch of salt. Potatoes absorb some of it as they cook, which seasons them from the inside.\r\n\r\n## How to tell when they are done\r\n\r\nDo not rely on the timer alone. Use it to know when to start checking.\r\n\r\n- **The knife test.** Push a thin knife or skewer into the largest piece. If it slides in with almost no resistance and the potato slips off easily, it is done.\r\n- **For potato salad,** stop when the knife goes in with just a little resistance. The potatoes will keep cooking slightly as they cool, and they will hold their shape.\r\n- **For mash,** cook until the knife meets no resistance at all and the edges are just starting to soften. Undercooked potatoes make lumpy mash no matter how hard you work them.\r\n\r\nA sensible plan is to set a timer for the low end of the range, check, then add two or three minutes at a time.\r\n\r\n## A worked example: mash for four\r\n\r\nSay you want mashed potatoes ready at 7:30 pm.\r\n\r\n- **1 kg floury potatoes**, peeled and cut into 2.5 cm cubes.\r\n- Cold salted water to start, about 8 to 10 minutes to come to the boil on a typical hob.\r\n- Then about 12 to 15 minutes at a gentle boil.\r\n- 5 minutes to drain, steam dry and mash.\r\n\r\nWorking backwards from 7:30: mash at 7:25, drain at 7:20, the water reaches a boil around 7:05 to 7:08, so the pot goes on the heat at about 6:57. Peeling and cutting 1 kg takes around 10 minutes, so start at about 6:45.\r\n\r\nTo keep it simple, start a [15-minute countdown](/countdown-timer?m=15) the moment the water comes to the boil. At 12 minutes, test a cube. If it is not quite there, give it another two or three.\r\n\r\n### Steps for good mash\r\n\r\n1. **Drain well.** Tip the potatoes into a colander and let them sit for a minute or two.\r\n2. **Steam dry.** Put them back in the empty, hot pan off the heat for a minute. Excess water makes mash heavy and thin.\r\n3. **Warm your dairy.** Heat the milk and melt the butter before adding them. Cold milk cools the mash and makes it gluey.\r\n4. **Mash, then stir.** Use a masher or ricer. Avoid a blender or food processor, which overworks the starch and turns the mash sticky.\r\n5. **Season at the end.** Taste, then add salt and pepper.\r\n\r\nA rough starting ratio is 1 kg potatoes to 50-75 g butter and 100-150 ml warm milk. Adjust to taste.\r\n\r\n## Boiling potatoes for other dishes\r\n\r\n**Potato salad.** Use waxy potatoes, halved or in 3 cm chunks. Boil for about 12 to 15 minutes until just tender. Dress them while they are still warm so they absorb the flavour, then let them cool.\r\n\r\n**Roast potatoes.** Parboil 4-5 cm chunks of floury potatoes for 8 to 10 minutes, until the edges are soft but the centres are still firm. Drain, shake them in the colander to rough up the surfaces, then roast in hot fat. The fluffy edges become the crispy bits.\r\n\r\n**Curries and stews.** If potatoes go straight into a simmering curry or stew, they usually take 15 to 25 minutes depending on size. Parboiling for 5 to 8 minutes first can shorten the cooking time in the pot.\r\n\r\n**Jacket-style potatoes in a hurry.** Boiling whole medium potatoes for 15 minutes before finishing them in a hot oven for 20 to 30 minutes gives a fluffy inside in less time than baking from raw.\r\n\r\n## Common mistakes\r\n\r\n- **A rolling boil.** Hard boiling breaks up the outside of the potatoes before the middle is ready. Once the water boils, turn it down to a steady, gentle bubble.\r\n- **Too little water.** If the potatoes are not covered, the top layer cooks more slowly.\r\n- **Lid on, then forgotten.** A lid helps the water return to a boil faster, but it also makes the pot more likely to boil over. Set it slightly ajar, or remove it once boiling.\r\n- **Leaving them sitting in the water.** Potatoes left in hot water after cooking keep softening and become waterlogged. Drain them as soon as they are done.\r\n\r\n## Storage and safety\r\n\r\nNHS food-hygiene advice is to cool leftovers as quickly as possible, ideally within 1 to 2 hours, then put them in the fridge and eat them within 2 days. Reheat until steaming hot all the way through, and do not reheat more than once. The NHS also advises not eating green, damaged or sprouting parts of potatoes, as these can contain toxins. Cut those bits away before cooking, and if a potato is mostly green, throw it out.\r\n\r\n## Quick checklist before you start\r\n\r\n- [ ] Pieces cut to roughly the same size\r\n- [ ] Cold, salted water covering them by 2-3 cm\r\n- [ ] Timer ready to start when the water boils, not when the pot goes on\r\n- [ ] Knife or skewer to hand for the first check\r\n- [ ] Colander in the sink so you can drain straight away\r\n\r\n## Try it with ClockAura\r\n\r\n![ClockAura's countdown timer set to 15 minutes for boiling potatoes](/images/how-long-to-boil-potatoes-clockaura.png)\r\n\r\nWe set the countdown to 15 minutes for the screenshot above, which matches 2.5 cm cubes for mash.\r\n\r\n1. Open the [countdown timer](/countdown-timer?m=15). The link loads 15 minutes for you.\r\n2. Change the minutes to suit your cut from the table, for example 12 for small new potatoes or 25 for medium whole ones.\r\n3. Press start the moment the water comes back to a boil.\r\n4. When it rings, do the knife test. If they need longer, add 2 or 3 minutes and start again.\r\n\r\n## FAQ\r\n\r\n**Do I need to peel potatoes before boiling?**\r\nNo. Skins on are fine for new potatoes, salads and rustic mash. Scrub them well. Peel for smooth mash.\r\n\r\n**Can I boil potatoes ahead of time?**\r\nYes. Boil, drain and cool them, then refrigerate. They reheat well in a pan, in the oven, or folded into hot mash.\r\n\r\n**How long to boil sweet potatoes?**\r\nCubes of about 2.5 cm take around 10 to 15 minutes, similar to ordinary potatoes, but they turn soft more quickly, so start checking early.\r\n\r\n**Why are my potatoes mushy outside and hard inside?**\r\nThey were probably too large, boiled too hard, or put into already boiling water. Cut them smaller, start in cold water and keep the boil gentle.\r\n\r\nFor other everyday cooking times, see our guides on [how long to boil pasta](/guides/how-long-to-boil-pasta) and [how long to cook rice](/guides/how-long-to-cook-rice).\r\n\r\n## Sources\r\n\r\n- NHS, [Starchy foods and carbohydrates](https://www.nhs.uk/live-well/eat-well/food-types/starchy-foods-and-carbohydrates/) (green and sprouting potatoes)\r\n- NHS, [Children's food: safety and hygiene](https://www.nhs.uk/baby/weaning-and-feeding/childrens-food-safety-and-hygiene/) (cooling, storing and reheating leftovers)","contentUpdatedAt":"2026-10-27T16:50:39.348Z","coverImage":"https://images.pexels.com/photos/15675493/pexels-photo-15675493.jpeg?auto=compress&cs=tinysrgb&w=1200","createdAt":"2026-10-27T16:50:39.349Z","excerpt":"Cubed potatoes take about 10 to 15 minutes, halved ones around 15 to 20, and large whole potatoes 20 to 30. Here is a full table by cut and size, how to test for doneness, and the small habits that make better mash.","publishedAt":"2026-10-27T16:50:39.348Z","status":"published","tags":["cooking","potatoes","boiling","mashed potatoes","kitchen timer","cooking times"],"title":"How Long to Boil Potatoes: Whole, Halved, Cubed and for Mash","updatedAt":"2026-10-27T18:34:05.885Z","views":10}