Most backyard farmers in the Philippines don't own a livestock scale. But you still need to know your pig's weight for three things: deciding when to sell, calculating feed amounts, and getting the right medication dosage from your vet.
The good news: a ₱30 tape measure and a simple formula gets you within 3-5% of actual weight. Here's how.
What You Need
- A soft measuring tape (the kind used for sewing), or any string plus a ruler
- A second person to hold the pig or keep it still
- A calculator or phone
That's it. Wala'y scale, wala'y problema.
How to Measure
You need two measurements, both in centimeters.
Heart girth (Libot sa dughan). Wrap the tape around the pig's body directly behind the front legs, at the narrowest part of the chest. Pull snug but not tight. Read the circumference in centimeters.
Body length (Gitas-on). Measure along the pig's back from the base of the ears (not the snout) to the base of the tail. Keep the tape along the spine, not hanging loose.
Take each measurement three times and average them. Pigs don't stand still, and a 2 cm error on heart girth can mean a 3-4 kg difference in your estimate. Measure while the pig is eating. It keeps them calmer.
The Formula
For improved breeds and crossbreeds (Landrace, Large White, Duroc crosses, and hybrids):
Weight (kg) = (Heart Girth cm × Heart Girth cm × Body Length cm) ÷ 10,840
Example: A crossbreed finisher with a heart girth of 103 cm and body length of 98 cm:
103 × 103 × 98 = 1,039,514 ÷ 10,840 = 95.9 kg
That pig is close to market weight. At the current farmgate floor price of ₱210/kg liveweight, that's roughly ₱20,100.
This formula is accurate to within ±3-5% for pigs between 30 and 130 kg. Outside that range, accuracy drops. For piglets under 20 kg, just weigh them on a kitchen scale or hanging scale (₱200-500 at hardware stores).
Quick Reference Table (Improved Breeds)
If math isn't your thing, use this table. Just measure heart girth and look up the approximate weight. This assumes typical body proportions for commercial crossbreeds.
| Heart Girth (cm) | Estimated Weight (kg) | Estimated Value at ₱210/kg |
|---|---|---|
| 65 | 25 | ₱5,250 |
| 70 | 34 | ₱7,140 |
| 75 | 44 | ₱9,240 |
| 80 | 53 | ₱11,130 |
| 85 | 62 | ₱13,020 |
| 90 | 71 | ₱14,910 |
| 95 | 80 | ₱16,800 |
| 100 | 89 | ₱18,690 |
| 105 | 98 | ₱20,580 |
| 110 | 107 | ₱22,470 |
| 115 | 116 | ₱24,360 |
Based on the linear regression model from Kansas State University extension research (r² = 0.98, ±4.5 kg accuracy at 95% confidence). Values rounded to nearest kg.
The ₱210/kg column uses the DA-mandated farmgate floor price as of late 2025. Actual prices in your area may be higher or lower. Check current regional prices before selling.
For Native Pigs: Use a Different Formula
The standard formula above was developed for improved Western breeds. Philippine native pigs have different body proportions (shorter, rounder). Research from the Philippine EJournals tested 54 native pigs (20-50 kg) and developed this formula:
Weight (kg) = -46.32 + (0.83 × Heart Girth cm) + (0.27 × Body Length cm)
Example: A native pig with heart girth 70 cm and body length 60 cm:
-46.32 + (0.83 × 70) + (0.27 × 60) = -46.32 + 58.1 + 16.2 = 28.0 kg
This model explains 92% of weight variation in Philippine native pigs (R² = 0.92). Heart girth alone accounts for 88%. So if you can only get one measurement on a squirmy native pig, heart girth is the one that matters.
Common Mistakes That Throw Off Your Estimate
- Measuring over the front legs instead of behind them. Heart girth goes right behind the legs, at the narrowest point. Measuring on top of the legs adds 5-8 cm and overestimates weight by 10+ kg.
- Measuring a pig that just ate or drank. A full gut adds 2-4 kg. Measure before the morning feeding for the most consistent result.
- Letting the tape hang loose. Snug, not tight. You should be able to slip one finger under the tape.
- Using the improved breed formula on native pigs. Native pigs are shorter and stockier. The standard formula can overestimate their weight by 15-20%. Use the Philippine native formula above.
- Not averaging multiple measurements. One reading is a guess. Three readings averaged is an estimate. Bahala ka kung usa ra, pero ayaw reklamo kung mali.
When a Tape Measure Isn't Enough
This method works for most backyard situations, but invest in a proper scale if:
- You sell more than 10 pigs per year. A hanging platform scale costs ₱3,000-8,000 and pays for itself fast. Even a 3 kg underestimate on 10 pigs at ₱210/kg costs you ₱6,300 per batch.
- You dose medications by weight. Antibiotics and dewormers have narrow dosing windows. Off by 10 kg, you underdose (doesn't work) or overdose (wastes money, risks toxicity). Your vet can weigh with a livestock sling scale for accuracy.
- Viajeros are underestimating your pig's weight. "Mga 80 kilos ra na" when your tape says 95 kg. That's ₱3,150 you just lost. Having your own scale, or at least a documented tape estimate, gives you leverage.
Use our break-even calculator and profit simulator once you have weight estimates for your batch.
Bisaya / Cebuano
Para sa mga mag-uuma: Unsaon pagtimbang sa baboy nga walay scale
Duha ka sukod ang kinahanglan:
- Libot sa dughan (heart girth): sukda ang libot sa lawas sa baboy luyo sa atubangan nga mga tiil, sa pinakapino nga bahin sa dughan
- Gitas-on (body length): sukda gikan sa likod sa dalunggan hangtod sa gamot sa ikog
Formula (improved breeds): Timbang (kg) = (Heart Girth × Heart Girth × Body Length) ÷ 10,840
Formula (native pigs): Timbang (kg) = -46.32 + (0.83 × Heart Girth) + (0.27 × Body Length)
Tip: Sukda tulo ka beses ug kuhaa ang average. Mas sakto kung sukdon samtang nagkaon ang baboy.
Sources:
- Kansas State University: Heart Girth to Estimate Finishing Pig Weight: linear regression model, r² = 0.98
- ThePigSite: Weighing a Pig Without a Scale: standard girth × girth × length formula
- Philippine EJournals: Estimating Liveweight of Philippine Native Pigs: native pig regression formula, R² = 0.92, n=54
- DA Farmgate Floor Price: ₱210/kg liveweight as of November 2025
