Baby Weight Gain Calculator
Fill in the values and the answer updates as you type.
How the Baby Weight Gain Calculator works
Average gain per day = (current weight − birth weight) ÷ age in days. Many healthy babies lose up to about 10 percent of their birth weight in the first days and regain it by about 2 weeks. A typical gain is roughly 20 to 30 g per day in the first 3 months, then slower. Growth is judged on a chart over time, so use this to spot a trend and talk to your pediatrician about any concern. Example: with Birth weight 3300 g, Current weight 5200 g, and Age 60 days, the result is Average gain per day (g) = 31.7; Average gain per week (g) = 222; Total gain since birth (g) = 1,900.
Inputs and results
The Baby Weight Gain Calculator takes 3 inputs and gives 4 results.
What you enter
- Birth weight (g) — starts at 3300.
- Current weight (g) — starts at 5200.
- Age (days) — starts at 60.
What you get
- Average gain per day (g)
- Average gain per week (g)
- Total gain since birth (g)
- Change from birth weight (%)
Example: Baby Weight Gain Calculator with the starting values
With birth weight 3300 g, current weight 5200 g and age 60 days, the calculator returns:
| Average gain per day (g) | 31.7 |
|---|---|
| Average gain per week (g) | 222 |
| Total gain since birth (g) | 1,900 |
| Change from birth weight (%) | 57.6 |
Change any value above and the results update straight away.
Baby Weight Gain Calculator FAQ
How do I use the Baby Weight Gain Calculator?
Enter birth weight, current weight and age in the fields, then read average gain per day (g), average gain per week (g), total gain since birth (g) and change from birth weight (%) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Baby Weight Gain Calculator calculate?
Average daily and weekly weight gain since birth. It returns average gain per day (g), average gain per week (g), total gain since birth (g) and change from birth weight (%) from the 3 values you provide.
What values does the Baby Weight Gain Calculator start with?
It opens with birth weight 3300 g, current weight 5200 g and age 60 days so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Baby Weight Gain Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Baby Weight Gain Calculator for medical or health decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm medical or health decisions with a qualified professional. See the Disclaimer for more.