Ham Cooking Time Calculator
How long to heat or cook a ham by weight and type — fully cooked bone-in or boneless, spiral-cut, or an uncooked fresh ham — with the internal temperature to aim for and when to glaze.
Most hams sold are already cooked and only need reheating to 60 °C (140 °F): about 33–40 minutes per kilogram (15–18 per pound) for a whole bone-in ham at 160 °C (325 °F), less for boneless and spiral-cut, which dry out if overdone.
How the ham cooking time calculator works
Most hams sold are already cooked and only need reheating to 60 °C (140 °F): about 33–40 minutes per kilogram (15–18 per pound) for a whole bone-in ham at 160 °C (325 °F), less for boneless and spiral-cut, which dry out if overdone. A fresh, uncooked ham is roasted like pork to 71 °C (160 °F) at roughly 50 minutes per kilogram. Glaze in the last 20–30 minutes, once the surface is hot enough to set it.
Formula: minutes = kg × minutes per kg for the ham type; check the internal temperature
Worked examples
| Inputs | Oven time | Note |
|---|---|---|
| 4 kg bone-in cooked ham | 2 h 24 min | 2 h 24 min |
| 9 lb spiral-cut | 1 h 38 min | 1 h 38 min |
| 5 kg fresh ham | 4 h 10 min | 4 h 10 min to 71 °C |
FAQFrequently asked questions
How do I know if my ham is already cooked?
The label says “fully cooked”, “ready to eat” or “cook before eating”. Most cured hams from a supermarket or butcher are cooked; a fresh (green) ham is raw pork and looks pale.
Why is the target only 60 °C for a cooked ham?
Because it is already safe; you are warming it through. Heating a cooked ham to 71 °C dries it out, especially spiral-cut ones with all that surface exposed.
Should I cover it?
Yes, with foil and a splash of liquid in the pan, until the last half hour. Uncover to glaze so the sugars caramelise without the meat drying.
Can I cook it in a slow cooker?
A boneless cooked ham, yes — 2–4 hours on low with a little liquid, glazed at the end. Bone-in whole hams rarely fit; check the size.
Where these figures come from
- US FDA — Safe Minimum Internal Temperatures — the internal temperatures the roasting calculator targets
- NIST SP 811 — Guide for the Use of the International System of Units — the exact weight and volume conversions used throughout
- UK Food Standards Agency — food safety and labelling standards
Last checked: September 2026. Baking ratios follow standard baker's percentage practice; roasting guidance follows published safe internal temperatures.