Cooking Time Calculator

Knowing exactly how long to cook meat, fish, or poultry is critical for food safety and quality. Undercooking risks foodborne illness; overcooking produces dry, unpleasant results. This calculator gives you a precise cooking time based on the type of food, its weight, and your cooking method.

How to Use the Cooking Time Calculator

1. Select the food type (beef, lamb, pork, chicken, fish, or vegetables).
2. Enter the weight in kilograms or grams.
3. Choose the cooking method (roasting, grilling, frying, slow cooking, etc.).
4. Select your preferred doneness level where applicable (rare, medium, well done).
5. Click Calculate to receive the estimated cooking time and recommended internal temperature.

The Formula

Cooking time for roasting is typically expressed as minutes per kilogram at a given oven temperature, plus a fixed resting time.

For example: Roast beef at 180C = 20 minutes per kg (rare) / 25 minutes per kg (medium) / 30 minutes per kg (well done), plus 20 minutes resting.

For whole poultry (chicken or turkey): cooking time = 20 minutes per kg + 20 minutes, at 200C. Always verify by checking internal temperature rather than relying solely on time, as oven calibration and meat shape vary.

The safe internal temperature method is the most reliable. The calculator combines time estimates with target internal temperatures so you have two checkpoints.

Real-World Example

You have a 1.8kg whole chicken and want to roast it safely at 200C.

Formula: (20 min/kg x 1.8kg) + 20 min = 36 + 20 = 56 minutes.

Round up to 60 minutes and check the internal temperature. Insert a probe thermometer into the thickest part of the thigh, avoiding the bone. The reading must reach 75C (165F) before the bird is safe to eat. If it has not reached temperature at 60 minutes, continue roasting and check every 10 minutes. Rest for 10 to 15 minutes before carving to allow juices to redistribute.

Resting: Why It Matters

Resting is a step that many home cooks skip, but it makes a significant difference to the final result. When meat is in the oven, heat drives juices towards the centre. Taking it out and letting it rest on a warm plate (tented loosely with foil to retain heat) allows those juices to redistribute evenly through the meat. A joint that is carved immediately after removing from the oven will lose far more juice onto the board. As a general guide, rest small cuts for 5 minutes, steaks and chops for 5 to 10 minutes, and large roasts for 15 to 30 minutes.

Frequently Asked Questions

How does the cooking time change if I use a fan-assisted oven? Fan ovens circulate hot air and cook food roughly 15 to 20% faster than conventional ovens at the same temperature setting. Reduce the temperature by 20C or the cooking time by 10 to 15% when using a fan setting. The calculator allows you to specify fan or conventional mode to account for this.

Does starting with room-temperature meat change the cooking time? Yes. Meat taken directly from the fridge is cold in the centre and takes longer to reach the target internal temperature than meat that has been allowed to come to room temperature for 30 to 60 minutes. For large roasts, this can mean the difference of 10 to 20 minutes of additional cooking time.

What is the danger zone for food safety? The temperature range between 5C and 60C is considered the danger zone where bacteria multiply rapidly. Food should not spend more than 2 hours in total within this range (or 1 hour if the ambient temperature is above 32C). This means slow-cooker recipes that start from cold without a prior sear carry a food safety risk, which is why browning meat before slow cooking is often recommended.

Can I use the same calculator for fish? Yes. Fish cooks much faster than meat. A simple rule for fish fillets is 10 minutes per 2.5cm of thickness at 200C in a conventional oven. Fish is cooked when it flakes easily with a fork and the flesh is opaque throughout. Whole fish on the bone takes slightly longer. The target internal temperature for fish is 63C.

Also try these free tools:

• Safe Cooking Temperatures
• Recipe Scaler
• Nutrition Label Generator

Roast beef at three doneness levels

The page gives 20, 25 and 30 minutes per kilogram at 180C for rare, medium and well done, each with 20 minutes of resting. The rate applies to the weight and the resting time does not, so the table below separates them.

Because the resting time is a constant, the time does not scale with the weight. A joint of 1.5 kg takes 50 minutes at the rare rate and a joint of 3.0 kg takes 80 minutes, which is a factor of 1.6 rather than 2. The medium rate moves by a factor of 1.652174 and the well done rate by 1.692308. A cook who doubles the meat and doubles the time will overcook it, and the error grows with the size of the joint because the constant becomes a smaller share of the total.

Two chickens of different weights

Whole poultry follows the same shape at 200C: 20 minutes per kilogram plus 20 minutes, verified with a probe rather than the clock.

Doubling the weight from 1.2 kg to 2.4 kg raises the cooking time from 44 to 68 minutes, a factor of 1.545455. The rest is not optional and it is not dead time: the internal temperature continues to rise while the bird sits, so a joint pulled at exactly its target can read a degree or two higher after ten minutes.

Fan and conventional ovens

A fan circulates air and moves heat into the food faster. The page gives 15 to 20 percent faster cooking, or a 20C reduction in the setting, and the two adjustments are alternatives rather than additions.

The four settings span 11.2 minutes on the same bird, which is wider than the gap between a safe joint and a dry one. Pick the temperature route or the time route, and check with a probe either way.

Target internal temperatures

Time is an estimate and temperature is a measurement. The chart below gives the safe minimum internal temperatures published by the USDA Food Safety and Inspection Service, converted to Celsius.

Beef doneness sits on a different scale, and the two scales do not line up.

A rare joint at 52C sits below the USDA minimum of 62.7778C for whole cuts, which is why the federal chart and a chef's doneness chart are not interchangeable. The federal figure assumes a three-minute rest, and the rest is part of the control rather than a serving preference: the surface heat continues to move inward while the meat stands. A cook who wants a rare centre and a cook who wants the published minimum cannot both be satisfied by the same reading, and the choice is better made deliberately than by accident.

One rounding is worth flagging for anyone working across both scales. The poultry target printed elsewhere on this page reads 75C against 165F. Converting 165F gives 73.8889C, so the two forms of the same target sit about a degree apart. A probe checked against one figure will read differently from a probe checked against the other, and the Fahrenheit figure is the one the chart publishes.

Method and assumptions behind the time estimates

The time figures assume a conventional oven brought to the stated temperature, one unstuffed joint or bird, and meat that went in cold from the fridge. Four things move the answer more than the formula does.

• Oven calibration. Domestic ovens commonly sit 10 to 20 degrees away from their dial, so a 200C setting may deliver 185C or 215C. An oven thermometer costs less than a spoiled roast.
• Starting temperature. Meat from the fridge takes 10 to 20 minutes longer than meat that has stood at room temperature for half an hour, with the difference growing with the size of the joint.
• Shape and bone. A flat joint cooks through faster than a rolled one of the same weight, and bone conducts heat to the centre faster than meat does.
• Door openings. Each look drops the oven temperature and adds time, which is why the probe is better than the clock for deciding when to stop.

The food safety frame sits around all of it. Bacteria multiply fastest between 5C and 60C, so cooked food should spend no more than two hours in total in that range, and no more than one hour when the room is above 32C. Holding a roast warm for a long lunch pushes against that limit, and a slow cooker that starts from cold spends longer in the range than most cooks expect.

A note on the temperature chart

The safe minimum internal temperatures above come from the USDA Food Safety and Inspection Service chart. It sets whole cuts of beef, pork, veal and lamb at 145F (62.8C) with a rest of at least three minutes, ground meats at 160F (71.1C), and all poultry, including ground poultry, giblets and stuffing, at 165F (73.9C). The chart measures with a food thermometer before the food leaves the heat source, which is the detail that separates it from a time-based rule. A roast that has been in the oven for the calculated time and has not reached temperature is not cooked, whatever the clock says.