Pork Roast Cooking Times: Per Kg, Pound & Calculator

Few cooking moments feel more satisfying than carving a pork roast with crackling that crackles. Getting the timing right means the difference between guesswork and a centerpiece that earns its place on the Sunday table. Here is what reliable sources say about cooking times per kilogram, oven temperatures, and the final temperature that keeps you safe.

Standard time per 500g: 20 minutes + 20 minutes · Internal temperature: 72°C · High heat start: 15-20 minutes at 220°C · Oven temp after sear: 180°C/160°C fan · Rest time: 15-20 minutes

These benchmarks come from multiple recipe sites, butchers, and food authority sources.

How long do you cook a pork roast per kg?

Per 500g guidelines

The baseline formula most butchers and recipe sites settle on: 20 minutes per 500g plus an additional 20 minutes. That works out to roughly 44 minutes total per kilogram, adjusted by the high-heat starting blast. A 1kg joint gets about 44 minutes from the first minute in the oven. A 2kg joint runs closer to 88 minutes before resting.

• Loin: 30-40 minutes per kg
• Shoulder: 45 minutes per kg (or longer for fall-apart tenderness)
• Belly: 44 minutes per kg plus 20 minutes over

Adjustments for loin vs belly

Different cuts need different approaches. Pork loin is leaner and cooks faster, reaching safe internal temperature more quickly than fattier cuts. Pork shoulder contains more connective tissue and benefits from longer cooking at moderate temperatures to break that tissue down into tender strands. Belly pork, with its layered fat and meat, sits somewhere between the two.

BBC Good Food recommends a longer low-and-slow phase for shoulder—2.5 to 3 hours at 180°C/160°C fan with a boiling water base in the tin—followed by a high blast for crackling. That slower start renders the fat without drying the meat.

What this means: the cut you choose determines whether you need a timer or a thermometer to judge doneness.

Calculator basics

Working in imperial measurements adds a conversion step. One pound equals roughly 0.45kg, so 35 minutes per pound translates to approximately 77 minutes per kilogram. Apply the formula: multiply your joint weight in pounds by 35 minutes for total cook time, then add the initial high-heat blast.

GoodtoKnow offers the clearest simplified rule: 30 minutes high heat, then 30 minutes per 500g. That puts a 2kg joint at 30 minutes at 220°C plus 2 hours at 180°C. BBC Good Food’s herb-studded loin recipe follows a similar pattern with a 15-minute high start followed by 90 minutes at 180°C/160°C fan.

What is the cooking time for a pork roast?

General timelines

Across sources, three methods dominate. RecipeTin Eats uses a two-stage approach: slow roast pork shoulder at 160°C/320°F (140°C fan) for 2.5 hours, then blast at 250°C/485°F for 30 minutes. BBC Good Food prefers a water-base method with the same temperatures. Easy Peasy Foodie recommends starting at 240°C/220°C fan for 30 minutes, then dropping to 200°C/180°C fan for the remainder.

For a 2kg pork loin, the practical timeline looks like this: 15 minutes at 220°C, then approximately 80 minutes at 180°C/160°C fan to reach 70°C internal, followed by a 15-20 minute rest that carries the temperature to a safe 75°C.

Using a meat thermometer

Timing formulas help plan the day, but a meat thermometer tells you when the roast is actually done. Remove the pork at 70°C internal, and carry-over cooking during the rest period will push it to 75°C—matching the UK FSA safety threshold. Kitchen Sanctuary notes that resting uncovered preserves the crackling crispness, so resist the urge to cover the joint immediately after pulling it from the oven.

The implication: a thermometer removes guesswork from timing, which varies by cut, starting temperature, and oven calibration.

What is the 6 2 2 rule for pork?

Breakdown of the rule

The “6-2-2 rule” occasionally appears in cooking discussions but lacks consistent documentation across verified recipe sources. The most plausible interpretation based on available references suggests a 6% salt brine, followed by a 2-hour cook phase, then a 2-hour rest—but this framing does not appear in major recipe publications or butcher guides.

Application to roasts

Mainstream sources focus on the high-heat blast method rather than this formula. If you encounter the 6-2-2 rule in older cookbooks or informal guides, treat it as a historical or regional variation rather than a standard. The consistent, widely-cited approach across BBC Good Food, GoodtoKnow, and RecipeTin Eats is the two-stage high-heat then low-heat method.

What this means: the 6-2-2 rule may have merit in specific contexts, but no tier-1 or tier-2 source corroborates it as a standard pork roasting method.

Should I cover pork with foil when cooking?

Foil for moisture

Foil has a legitimate role during the slow-roast phase. Placing foil loosely over the skin during the first hour prevents it from burning before the fat has rendered. Some cooks also add a little water to the roasting tin to create steam that keeps the meat moist throughout the longer cooking phase.

Uncovered for crackling

The critical point: remove the foil before the final high-heat blast. Kitchen Sanctuary recommends an uncovered final 20-30 minutes at high temperature to achieve crispy crackling. Easy Peasy Foodie notes that the sudden heat blast is what makes the crackling bubble and puff up. If crackling fails to form, GoodtoKnow suggests cutting it off and returning it to the top oven position during the resting phase—it can recover without further cooking.

What are common mistakes when cooking pork roast?

Overcooking

The most frequent error is pulling the roast too late. Pork shoulder especially suffers from excessive heat—it dries out and toughens rather than falling apart tenderly. The solution is straightforward: use a thermometer and remove at 70°C internal, not 75°C. The carry-over rest does the rest.

Poor seasoning

Scoring the skin, drying it thoroughly, and applying salt generously before roasting are non-negotiable for crackling. Easy Peasy Foodie emphasizes patting the skin dry twice before salting, noting that moisture is the enemy of crispy results. Rich Harris from Waitrose demonstrates the technique on their YouTube channel: dry overnight in the fridge, bring to room temperature for 30 minutes, score in a diamond pattern, and salt liberally before the high-heat start.

Skipping the rest

Cutting into the roast immediately after pulling it from the oven guarantees juice loss. The Social Foodies and PJ Dale both recommend resting uncovered for 15-20 minutes. This period lets the juices redistribute throughout the meat and allows the internal temperature to finish rising to the safe threshold.

The catch: skipping the rest costs you both texture and safety margin—a 5°C carry-over rise that brings the pork to the FSA threshold of 75°C.

How to cook pork roast step by step

1. Remove the pork from the refrigerator 30 minutes before cooking. Bring the joint to room temperature for more even heat distribution.
2. Preheat the oven to 220°C (200°C conventional) for at least 30 minutes before the roast goes in.
3. Pat the pork skin dry with kitchen paper. Score the skin in a diamond pattern using a sharp knife, cutting through the fat but not into the meat.
4. Season liberally with salt. Apply a second round of salt after scoring to draw out additional moisture.
5. Place the pork in a roasting tin and position it in the top third of the oven for the highest initial heat.
6. Roast at 220°C for 15-20 minutes to start the crackling.
7. Reduce the oven temperature to 180°C/160°C fan. Continue roasting using the formula: 20 minutes per 500g plus 20 minutes.
8. Check internal temperature with a meat thermometer. Remove at 70°C to account for carry-over cooking.
9. Rest uncovered for 15-20 minutes before carving.

Easy Peasy Foodie (Food Blogger)

This sudden blast of heat is the key to crispy crackling.

UK Food Standards Agency (Government Authority)

Pork needs to reach an internal temperature of 75°C for 2 minutes to kill off any harmful bacteria.

Kitchen Sanctuary (Food Blogger)

That final blast of heat will make the crackling bubble and puff up and is key to crispy crackling.

For home cooks weighing these variables, the practical takeaway is clear: the formula gets you in the ballpark, but the thermometer decides when you pull it. Fan ovens require roughly 20°C lower temperatures than conventional settings. Skipping the rest after roasting costs you both texture and safety margin. Plan for 15-20 minutes of uncovered resting time, and resist the urge to cover the skin until the crackling has had its final high-heat moment to set.