With grids of num­bers, the ty­po­graphic logic must fol­low the math­e­mat­i­cal logic. If it doesn’t, your ty­pog­ra­phy is likely to con­fuse or mis­lead your read­ers about the mean­ing of the numbers.

Un­like let­ters in words, a digit in a num­ber has in­de­pen­dent mean­ing based on its po­si­tion rel­a­tive to the dec­i­mal point (which may be im­plied). That’s how we can tell that the dig­its in .49 rep­re­sent a num­ber that’s smaller than 49. Also un­like words, dif­fer­ent types of num­bers have dif­fer­ent rules about how they can be com­bined and compared.

Your goal when type­set­ting grids of num­bers is to make sure the ty­pog­ra­phy re­flects the un­der­ly­ing mean­ing of the num­ber. To do this, there is one golden rule: in any col­umn, dig­its with the same mean­ing must be ver­ti­cally aligned with each other. This means that you shouldn’t merely se­lect every­thing and ap­ply the same for­mat­ting to every­thing. Dif­fer­ent kinds of num­bers need dif­fer­ent typography.

1. Num­bers im­prop­erly aligned.

2. Table cell mar­gins too small.

3. Need­lessly thick rules and bor­ders.

4. Line spac­ing uneven.

5. In­apt sys­tem font (Calibri).

1. In­voice num­bers aligned right.

2. Net-worth val­ues have cur­rency sym­bols, com­mas, and cents. 

3. Weights and cur­rency aligned with dec­i­mal tabs (see tabs and tab stops) .

4. Zip codes are aligned left. 

5. Un­nec­es­sary col­ors and bor­ders removed.

6. Line spac­ing even.

7. Con­course in­stead of Calibri.

As for the col­umn la­bels, for­mat those af­ter you take care of the num­bers. Some­times you might need to make an in­con­sis­tent for­mat­ting choice to make them look right. For in­stance, in the re­vised ex­am­ple, the la­bel “Weight” is cen­tered, even though the num­bers un­der­neath are not.